METHOD FOR COATING A SUBSTRATE, A COATED SUBSTRATE, A MEDICAL DEVICE THEREOF, AND A METHOD CAPABLE OF KILLING A MICROBE Technical field The present invention generally relates to a method for coating a substrate and will be described in this context. The present invention also relates to a coated substrate, a medical device thereof and a method capable of killing a microbe. Background The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the invention. Biofilm formation, the organization of highly-ordered multicellular bacteria communities on a variety of surfaces in different environments, is a major impediment to the complete eradication of bacteria. This affects implantation of medical devices. Given their pervasive nature and recalcitrance to currently-known antimicrobials, biofilms have been known to play an integral role in the pathogenesis of persistent infections through the release of harmful toxins. These nosocomial infections are associated with significant social and economic ramifications, affecting approximately 10% of all hospitalized patients within the United States and resulting in an estimated 100, 000 deaths annually. As such, there is a need to develop a method to prevent or eradicate formation of biofilms. Common methods for preventing or eradicating biofilms that have been employed include the development of antibacterial and antifouling coatings to confer biofouling- resistant properties onto material surfaces. These methods are envisioned to work under two broad mechanisms: 1) an offensive strategy involving the eradication of bacteria; 2) a defensive strategy involving the repulsion of microorganisms to prevent fouling. However, current methods typically demonstrate antimicrobial and/or antifouling properties for a relatively short period of time. In addition, some methods that make use of antimicrobial agents based on peptides and synthetic polymers may have high manufacturing cost, which has limited their application. In light of the above, there exists a need to develop a method to prevent or eradicate formation of biofilms that can ameliorate or overcome at least one of the above disadvantages. Summary of Invention The present invention seeks to provide a method for coating a substrate that addresses the aforementioned need at least in part. The present invention also seeks to provide a coated substrate, a medical device thereof and a method capable of killing a microbe. Accordingly, in an aspect of the present invention, there is provided a method for coating a substrate, the method comprising: (a) contacting a functionalized polymer comprising a first functional group capable of reacting in a first click reaction and a second functional group capable of reacting in a second click reaction with a substrate comprising a first complementary functional group capable of reacting in the first click reaction with the first functional group to form a first layer; and (b) contacting a cationic polymer comprising a second complementary functional group capable of reacting in the second click reaction with the second functional group to form a second layer adjacent to the first layer; wherein the functionalized polymer comprises a structure in accordance with formula (I) and/or (II):

wherein P ¹ and P ² are polymer chains comprising repeat units of a carbonate; wherein for formula (I), the first functional group L ¹ of the functionalized polymer is located on a side chain of each repeat unit and the second functional group L ² is located on a terminal end of the functionalized polymer; wherein for formula (II), the first functional group L ¹ and the second functional group L ² of the functionalized polymer is located on a side chain of P ¹ and P ² respectively and R ¹ is an antifouling moiety located on a terminal end of the functionalized polymer;

wherein n and m represent the number of repeat units of each block, n is an integer greater than 1 and m is an integer greater than 1; and

wherein Z’ and Z’’ are monovalent end groups selected from the group consisting of hydrogen and a C1 to C40 alkyl; and wherein the cationic polymer comprise a structure in accordance with formula (III):

wherein C’ is a C2 to C15 divalent linking group;

wherein C’ comprises one, two, or three heteroatoms selected from the group consisting of nitrogen, oxygen and sulphur, wherein each heteroatom is linked to a polymer chain P ³ ;

wherein p is 1, 2 or 3;

wherein the polymer chain P ³ comprises repeat units of a carbonate;

wherein the second complementary functional group L ³ is located on a terminal end of the cationic polymer; and

wherein Z’’’ is a monovalent end group selected from the group consisting of hydrogen and a C1 to C40 alkyl. Preferably, the first functional group is a maleimide group and the first complementary functional group is a thiol group. Preferably, the second functional group is an alkyne and the second complementary functional group is an azide. Preferably, the method further comprises the step of adjusting the degree of polymerization (DP) of the functionalized polymer such that the DP is about 4 to about 32. Preferably, the method further comprises the step of adjusting the DP of the cationic polymer such that the DP is about 20 to about 60. Preferably, the polymer chain P ³ has a structure according to formula (P3):

wherein R’’’ is a C1 to C6 alkyl;

wherein L ^b -Q’(R ^a )u’ is a C5 to C25 cationic moiety comprising a quaternary ammonium group and/or a quaternary phosphonium group; wherein L ^b is a divalent linking group comprising at least 2 carbons; wherein Q’ is a tetravalent positively-charged nitrogen or phosphorus; wherein u’ has a value of 1 to 3;

wherein each R ^a group is a C1 to C10 alkyl;

wherein X’ is a negatively-charged ion. Preferably, p = 2 or 3. Preferably, one of the R ^a groups is a C3 to C10 alkyl and each of the other two R ^a groups is a methyl. Preferably, the polymer chain P ¹ has a structure according to formula (P1):

wherein R’ is a C1 to C6 alkyl; and

wherein the first functional group L ¹ may further comprise a C1 to C6 alkyl which links the first functional group L ¹ to the oxygen. Preferably, the polymer chain P ² has a structure according to formula (P2):

wherein R’’ is a C1 to C6 alkyl; and

wherein the second functional group L ² may further comprise a C1 to C6 alkyl which links the second functional group L ² to the oxygen. Preferably, the antifouling moiety R ¹ is poly(oxyalkylene), methoxypoly(oxyalkylene), poly(alkoxy acrylate) or a glycomimetic. Preferably, the antifouling moiety R ¹ is selected from the group consisting of poly(ethylene glycol) (PEG), methoxypoly(ethylene glycol) (MPEG), poly(methoxyethyl methacrylate), poly(ethoxyethyl methacrylate), poly(methoxyethyl acrylate) (PMEA) and poly(phosphorylcholine methacrylate). Preferably, the antifouling moiety R ¹ is MPEG having a molecular weight of 164 Da to 2.4 kDa. Preferably, the method further comprises the step of functionalizing the substrate so that the substrate comprises the first complementary functional group. In another aspect of the present invention, there is provided a coated substrate comprising: (a) a first layer comprising a functionalized polymer having a structure in accordance with formula (I) and/or (II):

wherein P ¹ and P ² are polymer chains comprising repeat units of a carbonate;

wherein for formula (I), the first functional group L ¹ of the functionalized polymer is located on a side chain of each repeat unit and the second functional group L ² is located on a terminal end of the functionalized polymer;

wherein for formula (II), the first functional group L ¹ and the second functional group L ² of the functionalized polymer is located on a side chain of P ¹ and P ² respectively and R ¹ is an antifouling moiety located on a terminal end of the functionalized polymer;

wherein n and m represent the number of repeat units of each block, n is an integer greater than 1 and m is an integer greater than 1; and wherein Z’ and Z’’ are monovalent end groups selected from the group consisting of hydrogen and a C1 to C40 alkyl; and

(b) a second layer comprising a cationic polymer having a structure in accordance with formula (III):

wherein C’ is a C2 to C15 divalent linking group; wherein C’ comprises one, two, or three heteroatoms selected from the group consisting of nitrogen, oxygen and sulphur, wherein each heteroatom is linked to a polymer chain P ³ ;

wherein p is 1, 2 or 3;

wherein the polymer chain P ³ comprises repeat units of a carbonate; wherein the functional group L ³ is a complementary functional group capable of reacting in the second click reaction with the second functional group L ² of the functionalized polymer as defined above; wherein the functional group L ³ is located on a terminal end of the cationic polymer; and

wherein Z’’’ is a monovalent end group selected from the group consisting of hydrogen and a C1 to C40 alkyl. Preferably, the first functional group is a maleimide group and the first complementary functional group is a thiol group. Preferably, the second functional group is an alkyne and the second complementary functional group is an azide. Preferably, the DP of the functionalized polymer is about 4 to about 32. Preferably, the DP of the cationic polymer is about 20 to about 60. Preferably, the polymer chain P ³ has a structure according to formula (P3):

wherein R’’’ is a C1 to C6 alkyl; wherein L ^b -Q’(R ^a )u’ is a C5 to C25 cationic moiety comprising a quaternary ammonium group and/or a quaternary phosphonium group; wherein L ^b is a divalent linking group comprising at least 2 carbons; wherein Q’ is a tetravalent positively-charged nitrogen or phosphorus; wherein u’ has a value of 1 to 3;

wherein each R ^a group is a C1 to C10 alkyl;

wherein X’ is a negatively-charged ion. Preferably, p = 2 or 3. Preferably, one of the R ^a groups is a C3 to C10 alkyl and each of the other two R ^a groups is a methyl. Preferably, the polymer chain P ¹ has a structure according to formula (P1):

wherein R’ is a C1 to C6 alkyl; and

wherein the first functional group L ¹ may further comprise a C1 to C6 alkyl which links the first functional group L ¹ to the oxygen. Preferably, the polymer chain P ² has a structure according to formula (P2):

wherein R’’ is a C1 to C6 alkyl; and wherein the second functional group L ² may further comprise a C1 to C6 alkyl which links the second functional group L ² to the oxygen. Preferably, the antifouling moiety R ¹ is poly(oxyalkylene), methoxypoly(oxyalkylene), poly(alkoxy acrylate) or a glycomimetic. Preferably, the antifouling moiety R ¹ is selected from the group consisting of poly(ethylene glycol) (PEG), methoxypoly(ethylene glycol) (MPEG), poly(methoxyethyl methacrylate), poly(ethoxyethyl methacrylate), poly(methoxyethyl acrylate) (PMEA) and poly(phosphorylcholine methacrylate). Preferably, the antifouling moiety R ¹ is MPEG having a molecular weight of 164 Da to 2.4 kDa. In another aspect of the present invention, there is provided a medical device comprising a coated substrate as described above. In another aspect of the present invention, there is provided a method capable of killing a microbe, the method comprising contacting the microbe with a coated substrate as described above. Preferably, the microbe is a Gram-positive microbe or a Gram-negative microbe. Other aspects of the invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. Brief Description of Figures The accompanying figures illustrate a non-limiting embodiment or reaction scheme and serve to explain the principles of the disclosed embodiments. The present invention will now be described, by way of example only, with reference to the accompanying figures, in which: Fig. 1 illustrates GPC traces of various polymers, (a) first layer polymers before deprotection; (b) first layer polymers before and after deprotection; and (c) second layer polymers before quaternization. Fig.2 illustrates ¹ H NMR spectra of (a) polymers 1d (before deprotection), (b) 1d (after deprotection) (c) 2b (before quaternization), (d) 2b’ (quaternized with dimethylbutylamine) and (e) 2b” (quaternized with dimethyloctylamine); Fig. 3 is a schematic presentation of a two-layer coating method that makes use of antifouling and antimicrobial polymers in accordance with embodiments of the present invention; Fig. 4 illustrates surface characterization of polymer coatings with high-resolution N(1s) XPS spectra and static water contact angle. Compared with (a) pristine PDMS and (b) silanized PDMS, the appearance of N(1s) peaks and decrease of static contact angles confirm the successful coating of polymers (c) 1b, (d) 1b+2b’, (e) 1b+2d’’, (f) 1d, (g) 1d+2b’, (h) 1d+2d’’, (i) 1e and (j) 1e+2d’’; Fig. 5 illustrates XPS high resolution S2p scan of uncoated and various polymer- coated surfaces; Fig. 6 illustrates antimicrobial efficacy of polymer-coated surfaces. (a) Two-layer coatings containing the first layer grafting polymers 1a (DP = 6) and 1b (DP = 15) and cationic polymer 2b’ as the second layer grafting polymer to form two-layer coatings 1a+2b’ and 1b+2b’ effectively killed S. aureus after one-day incubation, while antimicrobial efficacy was much lower when polymer 1c with DP = 34 was used as the first layer grafting polymer. (b) Effect of cationic polymer length in the second-layer grafting polymers on antimicrobial efficacy against S. aureus after one-day incubation. The cationic polymer 2b’ (DP = 40) exerted the strongest antimicrobial efficacy (1b+2b’ vs.1b+2a’ and 1b+2c’). (c) Effects of cationic polymer length, hydrophobicity of quaternizing agents and architecture on antimicrobial efficacy against P. aeruginosa after one-day incubation. The coatings containing 3-arm cationic polymers with strong hydrophobicity (1b+2e” and 1e+2e”) completely eradicated the difficult-to-kill P. aeruginosa. Circles represent zero bacteria counts; Fig.7 illustrates minimum inhibitory concentrations (MICs) of cationic polycarbonates against (a) S. aureus and (b) P. aeruginosa in solution; Fig. 8 illustrates antifouling activity of polymer-coated surfaces. Viable surface colonies of (a) S. aureus and (b) P. aeruginosa on uncoated and coated surfaces after 1, 7 and 14 days of incubation with the bacteria. The two-layer coatings 1d+2b’ and 1b+2e”/1d+2e”/1e+2e” prevented fouling of S. aureus and P. aeruginosa over 2 weeks, respectively. Circles indicate that no live bacteria were found on the surface; Fig.9 illustrates prevention of S. aureus biofilm formation over 14 days. (a) Confocal laser scanning microscopic images of live and dead bacterial cells on the pristine and polymer-coated silicone surfaces after 1, 7 and 14 days of incubation (green denotes live and dead cells; red denotes dead cells). Size of scale bars: 20 µm; (b) FE-SEM images of bacterial cells after 1, 7, and 14 days of incubation on uncoated and polymer-coated PDMS surfaces. Size of the scale bars: 10 µm. The coating consisting of PEG-containing polymer 1d as the first layer and cationic polymer 2b’ as the second layer effectively prevented bacteria from fouling over 2 weeks; Fig. 10 illustrates prevention of P. aeruginosa biofilm formation over 14 days. (a) Confocal laser scanning microscopic images of live and dead bacterial cells on the pristine and polymer-coated silicone surfaces after 1, 7 and 14 days of incubation (green denotes live and dead cells; red denotes dead cells). Size of scale bars: 20 µm; (b) FE-SEM images of bacterial cells after 1, 7, and 14 days of incubation on uncoated and polymer-coated silicone surfaces. Size of the scale bars: 10 µm. The coatings consisting of 1b, 1d or 1e and 2e” of 2-arm, long cationic polymer and high hydrophobicity effectively prevented bacteria fouling over 2 weeks; Fig.11 illustrates P. aeruginosa biofilm formation on coated surfaces without cationic polymer. (a) Confocal laser scanning microscopic images of live and dead bacterial cells on the various first layer polymer-coated silicone surfaces after 1, 7 and 14 days of incubation (green denotes live and dead cells; red denotes dead cells). Size of scale bars: 20 µm; (b) FE-SEM images of bacterial cells after 1, 7, and 14 days of incubation on uncoated and polymer-coated silicone surfaces. Size of the scale bars: 10 µm; Fig.12 illustrates antimicrobial efficacy of polymer-coated surfaces against S. aureus after one-day incubation. 1f’: cationic polymer as the first coating layer; 2g ^# and 2h ^# : antifouling polymers containing PEG164 and PEG2.4k, respectively. Circles indicate no live bacteria were found on the surface; Fig.13 illustrates prevention of protein fouling by studying protein fouling on uncoated and various polymer-coated PDMS surfaces via observation of BSA-FITC using fluorescence microscopy; Fig.14 illustrates hemolytic activity of uncoated and various polymer-coated surfaces against rat red blood cells; Fig.15 illustrates an analysis of platelet adhesion on uncoated and various polymer- coated surfaces using FE-SEM. Definitions The following words and terms used herein shall have the meaning indicated: As used herein, the term "antifouling moiety" refers to a molecular group that is capable of inhibiting the attachment and/or growth of a biofouling organism. In various embodiments, the antifouling moiety may be part of a polymer residue. Suitable polymer residues include, but are not limited to, poly(ethylene glycol) (PEG), methoxypoly(ethylene glycol) (MPEG), poly(methoxyethyl methacrylate) and poly(ethoxyethyl methacrylate), poly(methoxyethyl acrylate) (PMEA), poly(phosphorylcholine methacrylate), and glycomimetic. As used herein, the term“antimicrobial” refers to the ability to kill or inhibit the growth of a microbe. As used herein, the term "antibacterial" refers to the ability to kill ("bacteriocidal") or inhibit bacterial growth ("bacteriostatic") or kills bacteria. As used herein, the term“click chemistry reaction” is used interchangeably with the term“click reaction” and it refers to a reaction between a functional group capable of reacting in the click reaction and a complementary functional group capable of reacting in the click reaction. In various embodiments, a click reaction may occur between a highly specific reactant pair, wherein each reactant pair is made up of a functional group capable of reacting in the click reaction and a complementary functional group capable of reacting in the click reaction. Furthermore, the click reaction may be chemoselective in nature, meaning that a first functional group capable of reacting in the click reaction would mainly or predominantly react with a first complementary functional group and not other functional groups. As used herein, the term“feed ratio” refers to the molar feed ratio. For instance, a feed ratio of MTC-FPM: MTC-Alkyne: Initiator = 10: 0: 1 refers to the use of 10 equivalents of MTC-FPM, no MTC-Alkyne and 1 equivalent of initiator. As used herein, the term“minimum inhibitory concentration (MIC)” is defined as the minimum concentration (in mg/L) of polymer required to inhibit growth of a given microbe for a period of time. A lower MIC indicates higher microbial activity. Unless specified otherwise, the terms“comprising”,“comprise”, and grammatical variants thereof, are intended to represent“open” or“inclusive” language such that they include recited elements but also permit inclusion of additional, unrecited elements. The terms“including”,“include”, and grammatical variants thereof are construed similarly. As used herein, the term“about” may refer to +/- 5% of the stated value, more preferably +/- 4% of the stated value, more preferably +/- 3% of the stated value, more preferably +/- 2% of the stated value, even more preferably +/- 1% of the stated value, and even more preferably +/- 0.5% of the stated value. Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as a limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. Ranges are not limited to integers, and can include decimal measurements where applicable. This applies regardless of the breadth of the range. Detailed Description Provided herein is a method for coating a substrate which is capable of inhibiting, preventing or eradicating biofilm formation. Exemplary, non-limiting embodiments of the method will now be disclosed. In an aspect of the invention, there is provided a method for coating a substrate, the method comprising: (a) contacting a functionalized polymer comprising a first functional group capable of reacting in a first click reaction and a second functional group capable of reacting in a second click reaction with a substrate comprising a first complementary functional group capable of reacting in the first click reaction with the first functional group to form a first layer; and (b) contacting a cationic polymer comprising a second complementary functional group capable of reacting in the second click reaction with the second functional group to form a second layer adjacent to the first layer; Advantageously, there is a synergistic effect when the coating comprises the first layer and the second layer as described which is not achieved when the two layers are reversed such that the cationic polymer forms the first layer and the functionalized polymer forms the second layer. In particular, maximum (or significantly improved) antimicrobial and antifouling activities may be achieved without inducing (or negligible) protein fouling, platelet adhesion and/or hemolysis. Furthermore, superior advantageous effects may be observed for the coating of the present invention as compared to a coating having only one layer. In particular, the coating may demonstrate antimicrobial and/or antifouling properties for a relatively long period of time, such as at least one week or at least two weeks. In various embodiments, the functional groups capable of reacting in the click reaction (including, but not limited to, the first functional group, the second functional group) and complementary functional groups capable of reacting in the click reaction (including, but not limited to, the first complementary functional group, the second complementary functional group) may be alkynyl groups, azido groups, nitrile groups, conjugated diene groups, epoxide groups, carbonyl groups, aziridine groups, thiol groups, maleimide groups or the like. Exemplary click chemistry reactions (or click reactions) can include, but are not limited to, 1,3-Huisgen dipolar cycloaddition (e.g. wherein the first functional group is an alkyne group and the first complementary functional group is an azide group), diels-alder cycloaddition (e.g. wherein the first functional group is a dienophile group and the first complementary functional group is a diene group), non-aldol carbonyl chemistry (e.g. wherein the first functional group is an isothiocyanate group and the first complementary functional group is an amine group), non-aldol carbonyl chemistry (e.g. wherein the first functional group is a ketone group and the first complementary functional group is an alkoxyamine group), non- aldol carbonyl chemistry (e.g. wherein the first functional group is an aldehyde group and the first complementary functional group is an alkoxyamine group), Michael addition (e.g. wherein the first functional group is an enolate group and the first complementary functional group is an alpha ketone group), Michael addition (e.g. wherein the first functional group is an enolate group and the first complementary functional group is a beta ketone group), Michael addition (e.g. wherein the first functional group is an enolate group and the first complementary functional group is an unsaturated ketone group), and nucleophilic ring opening reactions (e.g. wherein the first functional group is an epoxide group). In various embodiments, the functional groups capable of reacting in the click reaction and complementary functional groups capable of reacting in the click reaction have a high chemical potential energy and are therefore capable of producing highly selective, high yield reactions. In addition, the click reaction may occur in no solvent or in most solvents, including physiologic fluids, and often do not interfere with other reagents and reactions. In various embodiments, each adjacent layer of the coating is covalently joined by a different type of click chemistry reaction. For instance, a first layer of the coating may be formed on the substrate because a selective covalent bond is formed between the substrate and the functionalized polymer as a result of a click chemistry reaction between the first functional group and the first complementary functional group which is a functional group that is complementary to the first functional group. In various embodiments, the first functional group is a maleimide group and the first complementary functional group is a thiol group. A second layer of the coating which is adjacent to the first layer may be formed on the substrate because another selective covalent bond is formed between the functionalized polymer and the cationic polymer as a result of a click chemistry reaction between the second functional group and the second complementary functional group which is a functional group that is complementary to the first functional group. In various embodiments, the second functional group is an alkyne and the second complementary functional group is an azide. Consequently, a two-layer coating on the substrate is formed in a selective and desired manner. In various embodiments, the coating may comprise two or more layers. In various embodiments, the coating may comprise two layers, three layers, four layers or five layers. In various embodiments, the click reaction may be thermally initiated, such that it requires the application of heat. Advantageously, the click reaction may be carried out at room temperature, thereby providing a facile and environmentally friendly method. Furthermore, the method of the present invention may have a lower operating cost than prior art methods because heating is not required, thereby facilitating application of the method. In various embodiments, the click reaction may be catalyzed by a catalyst, such as a metal catalyst. In various embodiments, the metal catalyst is one or more metal selected from the group consisting of Au, Ag, Hg, Cd, Zr, Ru, Fe, Co, Pt, Pd, Ni, Cu, Rh, W, Ru, Pt, Ni, Cu, and Pd. Advantageously, the click reaction may not require the use of a catalyst, thereby providing a facile and cost effective method. More advantageously, the absence of a metal catalyst prevents the need for a work-up or purification method to remove the metal catalyst. In addition, there would not be any risk of the presence of trace amounts of the metal catalyst in the coating. In various embodiments, the functional groups may be protected so that the click chemistry reaction may be controlled and carried out when desired. For instance, if the first functional group is a maleimide group, the maleimide group may be protected using a furan group, thereby forming a furan-protected maleimide group. As such, the method of the present invention may comprise a deprotection step. The deprotection step may make use of heat, a solvent, an acid, a base or a combination thereof. For instance, deprotection of the furan-protected maleimide group may comprise the step of refluxing in a solvent such as toluene. In various embodiments, the functionalized polymer and the cationic polymer may comprise any type of polymer backbone. The polymer backbone of the functionalized polymer may be the same or different from the polymer backbone of the cationic polymer. Exemplary polymer backbones include, but are not limited to polymers, copolymers, polyelectrolyte polymers such as poly(acrylic acid) and poly(lysine), polyethers such as polyethylene glycol, polyesters such as poly(acrylates) and poly(methacrylates), polyalcohols such as poly( vinyl alcohol), polyamides such as poly(acrylamides) and poly(methacrylamides), biocompatible polymers, biodegradable polymers, polypeptides, polynucleotides, polycarbohydrates and lipopolymers. Exemplary thermoplastic polymers include, but are not limited to acrylonitrile butadiene styrenes, acrylics, celluloids, cellulose acetates, cyclic olefin copolymers, ethylene-vinyl acetates, ethylene vinyl alcohols, fluoroplastics, ionomers, polyacetals, polyacrylates, polyacrylonitriles, polyamides, polyamide-imides, polyaryletherketones, polybutadienes, polybutylenes, polybutylene terephthalates, polycaprolactones, polychlorotrifluoroethylenes, polyethylene terephthalates, polycarbonates, polyhydroxyalkanoates, polyketones, polyesters, polyethylenes, polyetherimides, polyethersulfones, polyethylenechlorinates, polyimides, polylactic acids, polymethylpentenes, polyphenylene oxides, polyphenylene sulfides, polyphthalamides, polypropylenes, polystyrenes, polysulfones, polytrimethylene terephthalates, polyurethanes, polyvinyl acetates, polyvinyl chlorides, polyvinylidene chlorides, styrene-acrylonitriles or any combination thereof. In various embodiments, the functionalized polymer is antifouling. The functionalized polymer may comprise a structure in accordance with formula (I):

L ² – [P ¹ (L ¹ )]n– Z’,

wherein P ¹ is a polymer chain comprising repeat units of a carbonate;

wherein the first functional group L ¹ of the functionalized polymer is located on a side chain of each repeat unit;

wherein the second functional group L ² is located on a terminal end of the functionalized polymer;

wherein n represents the number of repeat units and is an integer greater than 1; and wherein Z’ is a monovalent end group selected from the group consisting of hydrogen and a C1 to C40 alkyl. In various embodiments, the polymer chain P ¹ may have a structure according to formula (P1):

wherein R’ is a C1 to C6 alkyl; and

wherein the first functional group L ¹ may further comprise a C1 to C6 alkyl which links the first functional group L ¹ to the oxygen. In various embodiments, n may be an integer in the range of 1 to 40, 4 to 35, or 4 to 32. The integer n may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40. In various embodiments, the symbol“y” may be used in place of the symbol“n”. In various embodiments, the first functional group L ¹ of the functionalized polymer having a structure in accordance with formula (I) is a maleimide and the second functional group L ² of the functionalized polymer having a structure in accordance with formula (I) is an alkyne, thereby forming an alkyne- and maleimide-functionalized polycarbonate. In various embodiments, the functionalized polycarbonate may be synthesized using an organocatalytic ring-opening polymerization reaction (OROP). In various embodiments, an initiator selected from the group consisting of propargyl alcohol, propargyl bromide and propargyl chloride may be used in the OROP. In various embodiments, the functionalized polymer is a diblock polymer. The functionalized polymer may comprise a structure in accordance with formula (II): R ¹ – [P ¹ (L ¹ )] n– [P ² (L ² )] m– Z’’,

wherein P ¹ and P ² are polymer chains comprising repeat units of a carbonate;

wherein the first functional group L ¹ and the second functional group L ² of the functionalized polymer is located on a side chain of P ¹ and P ² respectively;

wherein R ¹ is an antifouling moiety located on a terminal end of the functionalized polymer;

wherein n and m represent the number of repeat units of each block, n is an integer greater than 1 and m is an integer greater than 1; and

wherein Z’’ is a monovalent end group selected from the group consisting of hydrogen and a C1 to C40 alkyl. In various embodiments, n may be an integer in the range of 1 to 40, 4 to 35, or 4 to 32. The integer n may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40. In various embodiments, m may be an integer in the range of 1 to 40, 4 to 35, or 4 to 32. The integer m may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40. In various embodiments, the symbol“y” may be used in place of the symbol“n”. In various embodiments, the polymer chain P ¹ may have a structure as described above and P ² may have a structure according to formula (P2):

wherein R’’ is a C1 to C6 alkyl; and

wherein the second functional group L ² may further comprise a C1 to C6 alkyl which links the second functional group L ² to the oxygen. In various embodiments, the antifouling moiety R ¹ of the functionalized polymer is a polymer residue selected from the group consisting of poly(oxyalkylene), methoxypoly(oxyalkylene), and poly(alkoxy acrylate). In various embodiments, the antifouling moiety R ¹ may be selected from the group consisting of poly(ethylene glycol) (PEG), methoxypoly(ethylene glycol) (MPEG), poly(methoxyethyl methacrylate), poly(ethoxyethyl methacrylate), poly(methoxyethyl acrylate) (PMEA), poly(phosphorylcholine methacrylate), and glycomimetic. In various embodiments, the antifouling moiety R ¹ has a molecular weight of about 100 Da to about 10,000 Da (10 kDa), about 1000 Da to about 10,000 Da, about 500 Da to about 10,000 Da, about 500 Da to about 5,000 Da, about 100 Da to about 5,000 Da, about 100 Da to about 4,000 Da, about 100 Da to about 3,000 Da, about 100 Da to about 2,000 Da, about 100 Da to about 2,400 Da, or about 164 Da to about 2,400 Da. In various embodiments, the antifouling moiety R ¹ is PEG or MPEG. Advantageously, the presence of PEG or MPEG results in enhanced resistance to protein and bacteria fouling over a relatively long period of time, such as at least one week or at least two weeks or at least three weeks or at least four weeks. In various embodiments, the antifouling moiety R ¹ is MPEG having a molecular weight of 164 Da to 2.4 kDa. In various embodiments, the first functional group L ¹ of the diblock polymer having a structure in accordance with formula (II) is a maleimide and the second functional group L ² of the diblock polymer having a structure in accordance with formula (II) is an alkyne. In various embodiments, the diblock polymer may be synthesized using OROP. In various embodiments, MPEG may be used as a macroinitiator in the OROP. In various embodiments, the method further comprises the step of adjusting the degree of polymerization (DP) of the functionalized polymer such that the DP is about 2 to about 40, about 4 to about 38, about 4 to about 36, about 4 to about 34, or about 4 to about 32. Advantageously, adjusting the DP of the functionalized polymer may positively affect the bacteria killing efficacy. For instance, when the DP is about 6 to about 15, 100% killing efficiency for S. aureus may be achieved after one-day incubation. In various embodiments, the functionalized polymer may have an average molecular weight (Mn) of about 2000 to about 20,000, about 2000 to about 10,000, about 5000 to about 20,000, about 5000 to about 10,000, or about 10,000 to about 20,000. Advantageously, the functionalized polymer may have a narrow molecular weight distribution and consequently a narrow PDI, thereby illustrating that the functionalized polymer is substantially homogenous or substantially uniform. In various embodiments, the cationic polymer is antimicrobial. Furthermore, the cationic polymer may be bio-compatible, biodegradable, non-hemolytic and non- cytotoxic. The cationic polymer may comprise a structure in accordance with formula

wherein C’ is a C2 to C15 divalent linking group;

wherein C’ comprises one, two, or three heteroatoms selected from the group consisting of nitrogen, oxygen and sulphur, wherein each heteroatom is linked to a polymer chain P ³ ;

wherein p is 1, 2 or 3; wherein the polymer chain P ³ comprises repeat units of a carbonate;

wherein the functional group L ³ is a functional group complementary to the second functional group L ² of the functionalized polymer as defined above;

wherein the functional group L ³ is located on a terminal end of the cationic polymer; and

wherein Z’’’ is a monovalent end group selected from the group consisting of hydrogen and a C1 to C40 alkyl. In various embodiments, C’ may comprise one heteroatom, wherein the heteroatom is oxygen and may be derived from a chemical component such as initiator 1, thereby forming a one-arm (1-arm) cationic polymer. In various embodiments, C’ may comprise two heteratoms, wherein each heteroatom is oxygen and may be derived from a chemical component such as initiator 2, thereby forming a two-arm (2-arm) cationic polymer. As such, the cationic polymer comprises two quaternary nitrogen- containing moieties. Advantageously, the two-arm cationic polymer may be able to prevent biofilm formation better than the one-arm and three-arm cationic polymers and/or exhibit better antimicrobial properties, such as antibacterial activity. In various embodiments, C’ may comprise three heteroatoms, wherein each heteroatom is oxygen and may be derived from a chemical component such as initiator 3, thereby forming a three-arm (3-arm) cationic polymer. As such, the cationic polymer comprises three quaternary nitrogen-containing moieties. In various embodiments, the polymer chain P ³ may have a structure according to formula (P3):

wherein R’’’ is a C1 to C6 alkyl; wherein L ^b -Q’(R ^a )u’ is a C5 to C25 cationic moiety comprising a quaternary ammonium group and/or a quaternary phosphonium group;

wherein L ^b is a divalent linking group comprising at least 2 carbons;

wherein Q’ is a tetravalent positively-charged nitrogen or phosphorus;

wherein u’ has a value of 1 to 3;

wherein each R ^a group is a C1 to C10 alkyl ;

wherein X’ is a negatively-charged ion. In various embodiments, x may be an integer in the range of 20 to 80, 30 to 80, or 40 to 80. In various embodiments, the symbol“m” may be used in place of the symbol “x”. In various embodiments, each R ^a group may independently comprise oxygen, nitrogen, sulphur and/or another heteroatom. Exemplary R ^a groups include but are not limited to methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, n-pentyl, n-hexyl, n- heptyl, n-octyl, n-nonane, n-decane and benzyl. In various embodiments, the Q’(R ^a )u’ group may be selected from the group consisting of:

In various embodiments and as illustrated above, one of the R ^a groups is a C3 to C10 alkyl and each of the other two R ^a groups is a methyl. In various embodiments, Q’ is nitrogen, thereby forming at least one quaternary nitrogen-containing moiety. Advantageously, the at least one quaternary nitrogen- containing moiety makes the cationic polymer exhibit antimicrobial activities. In various embodiments, the method may further comprise the step of using a quaternization reagent to form the Q’(R ^a )u’ group as described above. In various embodiments, the quaternization reagent may be selected from the group consisting of dimethylbutylamine, dimethyloctylamine, dimethylbenzylamine, and trimethylamine. In various embodiments, the negatively-charged ion X’ may be a halide (e.g., chloride, bromide, iodide), a carboxylate (e.g. acetate, benzoate), and/or a sulfonate (e.g. tosylate). In various embodiments, the cationic polymer may be synthesized using OROP. In various embodiments, the OROP may be carried out using a catalyst selected from the group consisting of 1,8-diazabicyclo[5.4.0]undec-7-enene (DBU), tin(II) 2- ethylhexanoate (Sn(Oct)2) and tin(II) trifluoromethanesulfonate (Sn(OTf)2). In various embodiments, the cationic polymer may have an average molecular weight (Mn) of about 1000 to about 30,000, about 1000 to about 20,000, about 1000 to about 10,000, about 5000 to about 20,000, about 5000 to about 15,000 or about 5000 to about 10,000. Advantageously, the cationic polymer may have a narrow molecular weight distribution and consequently a narrow PDI, thereby illustrating that the cationic polymer is substantially homogenous or substantially uniform. In various embodiments, the method comprises the step of adjusting the DP of the cationic polymer such that the DP is about 20 to about 100, about 20 to about 90, about 20 to about 80, about 20 to about 60, about 20 to about 50, about 20 to about 40, about 25 to about 60, about 25 to about 50, or about 22 to about 40. Advantageously, adjusting the DP of the cationic polymer may positively affect the bacteria killing efficacy. For instance, a higher bacteria killing efficacy for S. aureus may be achieved when the DP is about 22 to about 40 for one-arm cationic polymers, compared to when the DP is above 80. In various embodiments, the method comprises the step of functionalizing/modifying the substrate so that the substrate comprises a functional group complementary to the first functional group of the functionalized polymer. In various embodiments, the substrate may be functionalized/modified to comprise sulphur (such as in the form of a thiol group) and the first functional group of the functionalized polymer is a maleimide group, so that a first click reaction can occur, wherein the first click reaction is a Michael addition reaction between the maleimide group of the functionalized polymer to the thiol group of the substrate. In various embodiments, the substrate may be made of a (bio)degradable material or a removable material. In various embodiments, the substrate may be of any shape, form or template. For example, the substrate may be a planar substrate or a substantially planar substrate, a colloidal particle, a nanoparticle, a microsphere, a crystal, and the like. In various embodiments, the substrate may be made of any suitable material known in the art, including, but not limited to glass materials, ceramic materials, silicon materials, metal oxide materials, metal alloy materials, gold materials, quartz materials, indium tin oxide materials, antimony tin oxide materials, semiconductor materials, semiconductor alloy materials, organic materials (e.g. organic solid materials) and polymeric materials. The substrate may further comprise carbon nanotubes, polypeptides, peptides, organic polymers, polymer precursors, thermoplastic polymers, a blend of thermoplastic polymers, thermosetting polymers or any combination thereof. The substrate may further comprise a blend of polymers, copolymers, terpolymers, and can be a oligomer, a homopolymer, a copolymer, a block copolymer, an alternating block copolymer, a random polymer, a random copolymer, a random block copolymer, a graft copolymer, a star block copolymer, a dendrimer, or the like. In various embodiments, the substrate is silicone rubber which comprises silicone. Silicone is a ubiquitous material for many different devices, such as stents, catheters, prostheses, contact lenses and microfluidics. It has low transition temperature and is hydrophobic, allowing the material to be inert to intravenous and body fluids. Silicone is also nontoxic, and possesses both thermal and chemical stability, thereby making it an attractive material for biomedical applications. However, it is prone to protein adsorption due to its hydrophobic nature, and protein fouling can occur in a matter of seconds after implantation and exposure to body fluids, resulting in blood clots and subsequent thrombosis. Once proteins form on the topmost layer of the silicone surface, microbes can easily anchor onto the silicone surface. Advantageously, the coating of the present invention can prevent or eradicate microbes from anchoring onto the silicone surface. In another aspect of the invention, there is provided a coated substrate comprising: (a) a first layer comprising a functionalized polymer as described above and (b) a second layer comprising a cationic polymer as described above. In another aspect of the invention, there is provided a medical device comprising a coated substrate as described above. The medical device may be a scaffold, an adhesion barrier, a patch, a matrix, a plug, a bandages, a mesh and an implant such as a prosthetic including, but not limited to, a joint prosthetic, a dental implant, and a cosmetic implant. In another aspect of the invention, there is provided a method capable of killing a microbe, the method comprising contacting the microbe with a coated substrate as described above. In various embodiments, the microbe is a Gram-positive microbe, a Gram-negative microbe, a fungi, a yeast or a combination thereof. In various embodiments, the microbe is a Gram-positive bacteria such as Staphylococcus aureus (S. aureus), a Gram-negative bacteria such as Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), or a fungus such as Candida albicans (C. albicans). In various embodiments, a relatively high bacteria killing efficiency of S. aureus and P. aeruginosa may be obtained using the coated substrate of the present invention. In various embodiments, when the functionalized polymer of the first layer comprises an antifouling moiety R ¹ which is PEG or MPEG, the resultant coated substrate may advantageously exhibit enhanced resistance to S. aureus over a relatively long period of time, such as at least one week or at least two weeks, and may prevent biofilm formation. In various embodiments, when the cationic polymer of the second layer comprises a higher number of cationic charge and/or is a two-arm cationic polymer and/or has a relatively higher hydrophobicity may advantageously exhibit enhanced resistance to P. aeruginosa over a relatively long period of time, such as at least one week or at least two weeks, and may prevent biofilm formation. Examples

Non-limiting examples of the present disclosure will be further described, which should not be construed as in any way limiting the scope of the disclosure. Chemicals

CH3O-PEG-OH (MPEG, Mn 2.4 kD, PDI 1.05) was purchased from Polymer Source ^TM , lyophilized and transferred to a glove-box one day prior to use. N-(3,5- trifluoromethyl)phenyl-N’-cyclohexylthiourea (TU) was prepared according to a procedure reported by R. C. Pratt, B. G. G. Lohmeijer, D. A. Long, P. N. P. Lundberg, A. P. Dove, H. Li, C. G. Wade, R. M. Waymouth, J. L. Hedrick, Macromolecules 2006, 39, 7863. TU was dissolved in dry tetrahydrofuran and dried over CaH2 overnight. The mixture was filtered, and the solvent removed in vacuo.1,8-Diazabicyclo[5,4,0]undec- 7-ene (DBU) was dried over CaH2 overnight, and dried DBU was obtained after vacuum distillation. Both dried TU and DBU were transferred to a glove-box prior to use. FITC-conjugated bovine serum albumin (FITC-BSA), 3- mercaptopropyltrimethoxysilane and all other chemicals were purchased from Sigma- Aldrich, and used as received unless stated otherwise. Silicone Kit Sylgard ^TM 184 was bought from Dow Corning, and used according to the manufacturer’s protocols. LIVE/DEAD Baclight bacterial viability kit (L-7012) was obtained from Invitrogen. S. aureus (ATCC No.6538) and P. aeruginosa (ATCC No.9027) were purchased from ATCC (U.S.A). Characterization by proton nuclear magnetic resonance ( ¹ H NMR) spectroscopy The ¹ H NMR spectra of monomers and polymers were recorded on a Bruker Advance 400 NMR spectrometer, operated at 400 MHz and at room temperature. The ¹ H NMR measurements were performed using an acquisition time of 3.2 s, a pulse repetition time of 2.0 s, a 30º pulse width, 5208-Hz spectral width, and 32 K data points. Chemical shifts were referred to solvent peaks (δ = 7.26 and 1.94 ppm for CDCl3 and CD3CN-d6, respectively). Gel permeation chromatography (GPC)

Polymer molecular weights were analyzed by GPC using a Waters HPLC system equipped with a 2690D separation module, two Styragel HR1 and HR4E (THF) 5 mm columns (size: 300 × 7.8 mm) in series arrangement, coupled with a Waters 410 differential refractometer detector. THF was employed as the mobile phase at a flow rate of 1 mL·min ^-1 . Number-average molecular weights (Mn) and polydispersity indices (PDI) of polymers were calculated from a calibration curve based on a series of polystyrene standards with molecular weights ranging from 1350 to 151700. Preparation of Polydimethylsiloxane (PDMS)

PDMS silicone rubber was prepared by mixing 10 base parts to 1 curing part thoroughly, followed by degassing under vacuum for 30 min. The mixture was spin coated onto a Petri dish (for LIVE/DEAD cell staining and FE-SEM studies) using SAWATECH AG Spin Module SM-180-BT, or it was cast into a 48-well plate for XTT, Titer Blue ^® cell viability and colony assays. Both the Petri dish and plate were placed overnight in a vacuum oven at 70 ºC for curing. After curing, the PDMS sample formed in the Petri dish was cut into square pieces (0.5 cm × 0.5 cm with a thickness of about 1 mm). The disc-like PDMS samples were gently removed from the bottom of the 48- well plate with flat forceps. All PDMS samples were first sonicated with de-ionized (DI) water, followed by isopropanol and DI water. The samples were dried under a stream of nitrogen before use. Thiol-functionalization of PDMS surface by vapor deposition

Clean PDMS surface was exposed to ultraviolet/ozone (UVO) radiation for 1 h in a commercial PSD-UVT chamber (Novascan). The surface was then briefly exposed to humid air, and dried under a stream of nitrogen. Subsequently, the dried PDMS surface was placed on a clean piece of weighing paper in a small vacuum desiccator, together with 1 mL of 3-mercaptopropyltrimethoxysilane loaded in a clean vial. The vapor deposition process was carried out overnight with the desiccator sealed under vacuum at 70 ºC to provide thiol-functionalized surface. The treated surface was dried under a stream of nitrogen, and kept in a sealed desiccator at room temperature prior to use. Polymer coating

The first layer polymers of varying compositions (2 mg) were first dissolved in 1 mL of acetonitrile. Subsequently, the clean PDMS surface treated with 3- mercaptopropyltrimethoxysilane was immersed in the polymer solution for 1 day at room temperature. The polymer-coated PDMS samples were sonicated in a mixture of isopropropanol and water (1:1 volume ratio), and dried under a stream of nitrogen before transferring to a new vial. Copper sulfate anhydrous (0.5 mg) and ascorbic acid (3 mg) were dissolved in 1 ml of HPLC water, before dissolving the second layer of cationic polymers (2 mg) into the copper sulfate solution. The solution was then mixed well before transferring into vials where the first layer polymer-treated surfaces were held. The surfaces were immersed for another 1 day before washing with isopropanol and water under sonication, and subsequently dried under nitrogen atmosphere. X-ray photoelectron spectroscopy (XPS) analysis

XPS (Kratos Axis HSi, Kratos Analytical, Shimadzu, Japan) with Al Ka source (hν = 1486.71 eV) was used to analyze the difference in surface chemistry between uncoated and polymer-coated silicone surface. The angle between the surface of the sample and the detector was kept perpendicular at 90°. The survey spectrum ranged from 1100 to 0 eV, and was acquired with a pass energy of 80 eV. All binding energies were calculated with reference to C 1s (C–C bond) at 284.5 eV. Static contact angle measurements

The static contact angles of both uncoated and polymer-coated surfaces were measured by an OCA15 contact angle measuring device (Future Digital Scientific Corp., U.S.A.). DI water (20 µL) was used for all measurements. All samples were analyzed in triplicates, and the static contact angle data were presented as mean ± SD. Killing efficiency of uncoated and coated surfaces (colony assay)

The concentration of S. aureus or P. aeruginosa in Mueller-Hinton broth (MHB, cation- adjusted) was adjusted to give an initial optical density (O.D.) reading of 0.07 at the wavelength of 600 nm on a microplate reader (TECAN, Switzerland), which correlates to a concentration of Mc Farland 1 solution (3 × 10 ⁸ CFU· mL ^-1 ). The bacterial suspension was diluted by 1000 times to achieve a loading of 3 × 10 ⁵ CFU·mL ^-1 . Subsequently, 20 µL of this bacterial suspension was added to the surface of an uncoated or coated disc-like PDMS sample, which was placed in a 48-well plate. Additionally, 60 µL of MHB was added to the surface, and the 48-well plate was incubated at 37 ºC for 1, 7 or 14 days. The bacterial solution (10 µL) was then taken out from each well and diluted with an appropriate dilution factor. The bacterial solution was streaked onto an agar plate (LB Agar from 1st Base). The number of colony- forming units (CFUs) was tabulated and recorded after an incubation of about 18 h at 37 ^C. Each test was conducted in triplicates. Antifouling analysis of uncoated and coated surfaces

Antifouling activity of uncoated and coated surfaces was evaluated by quantitative measurement of live bacterial cells attached onto PDMS surface after various periods of incubation time. Briefly, S. aureus or P. aeruginosa in MHB (20 µL, 3 × 10 ⁵ CFU·mL- ¹ ) was seeded onto uncoated and coated PDMS surfaces, topped up with 60 µL of MHB, and cultured at 37 ºC for 1, 7 or 14 days. Each surface was washed thrice with sterile phosphate-buffered saline (PBS), and was carefully placed in individual 8-ml tube containing 1.5 ml PBS. Each tube was sonicated for 8 s to detach bacterial cells and viable counts in the resulting suspensions was obtained by plating on agar medium to enumerate bacteria. LIVE/DEAD Baclight bacterial viability assay

A LIVE/DEAD Baclight bacterial viability kit (L-7012, Invitrogen), containing both propidium iodide and SYTO ^® fluorescent nucleic acid staining agents, was used to label bacterial cells on the uncoated and coated PDMS surfaces. Briefly, the red- fluorescent dye propidium iodide, which only penetrates damaged cell membrane, was used to label dead bacterial cells. The green-fluorescent dye SYTO ^® 9, which can penetrate cells both with intact and damaged membranes, was used to label all bacterial cells. Bacteria solution (3 × 10 ⁵ CFU·mL ^-1 , 20 µL) was seeded onto the uncoated and coated PDMS surfaces, followed by incubation at 37 ºC for 1, 7 and 14 days. The surfaces were washed thrice with clean PBS after the bacterial suspension was removed. Subsequently, each PDMS sample was placed individually into a 48- well plate with 200 µL of a dye solution, prepared from a mixture of 3 µL of SYTO ^® (3.34 mM) and 3 µL of propidium iodide (20 mM) in 2 mL of PBS. The procedure was conducted at room temperature in the absence of light for 15 min. Eventually, the stained bacterial cells attached to the surfaces were examined under a Zeiss LSM 5 DUO laser scanning confocal microscope (Germany), and the images were obtained using an oil immersed 40× object lens at room temperature. Analysis of bacteria attachment and biofilm formation by Field Emission Scanning Electron Microscope (FE-SEM)

FE-SEM was employed to evaluate the attachment and biofilm formation of S. aureus or P. aeruginosa on the uncoated and coated PDMS surfaces. Bacteria solution (3 × 10 ⁵ CFU·mL ^-1 , 20 µL) was seeded onto the uncoated and coated PDMS surfaces, followed by incubation at 37 ºC for 1, 7 or 14 days. An additional 20 µL of MHB was added after every 24 h to prevent the bacteria culture medium from drying out. At the predetermined time points, the PDMS surfaces were washed thrice with sterile PBS, followed by fixation with 2.5% glutaraldehyde in PBS overnight. The fixed bacteria were dehydrated with a series of graded ethanol solution (25%, 50%, 75%, 95%, and 100%, 10 min each) before the PDMS samples were mounted for platinum coating. The PDMS samples were observed under FE-SEM (JEOL JSM-7400F, Japan). Protein fouling by fluorescence analysis

Individual surfaces were incubated overnight with 20 µL of FITC-BSA solution (1 mg/mL) at 37 ºC. The surfaces were then washed thrice with clean sterile PBS solution before they were observed under an inverted fluorescence microscope (Olympus IX71, U.S.A). Hemolysis test

Freshly obtained rat blood was diluted to 4 % (by volume) with PBS buffer. The red blood cell suspension in PBS (500 µL) was added into a 2 mL eppendorf tube, which contained uncoated or coated PDMS samples individually. The tube was incubated for 1 h at 37 ºC for hemolysis to proceed. After incubation, the tube was centrifuged at 2200 rpm for 5 min at room temperature. Aliquots (100 µL) of the supernatant from each tube were transferred to a 96-well plate, and hemoglobin release was measured at 576 nm using the microplate reader (TECAN, Sweden). In this procedure, the red blood cells in PBS were used as a negative control, while the red blood cells lysed with 0.2% Triton-X were used as a positive control. The absorbance analysis for red blood cells lysed with 0.2% Triton X was taken as 100% hemolysis. The calculation for percentage of hemolysis was as follow: Hemolysis (%) = [(OD576nm of the sample - OD576nm of the negative control) / (OD576nm of the positive control - OD576nm of the negative control)] × 100. The data was analyzed and expressed as mean and standard deviation of three replicates for quantification of each type of PDMS surface. Analysis of platelet adhesion

Platelets-rich plasma obtained from pig were provided by Prof. Jackie Ho’s lab (NUHCS). The uncoated and coated PDMS samples were immersed into the plasma for 1 h at 37 ^C, after which the samples were rinsed thrice with PBS. Subsequently, the surfaces were fixed and observed under FE-SEM under the same conditions as stated above. Example 1: Synthesis of azide-functionalized initiators

Azide-containing initiators were synthesized with 11-azide-1-undecanol as a single arm initiator (initiator 1), and subsequent coupling of 11-azide-1-undecanol with 2,2,5- trimethyl-1,3-dioxane-5-carboxylic anhydride for synthesis of two- and three-arm initiators (initiator 2 and 3, respectively). 1.1 Synthesis of 11-azido-undecanol (Initiator 1) Sodium azide (5 g, 0.02 mol) was first dissolved in dimethyl sulfoxide (150 mL), with subsequent addition of 11-bromo-1-undecanol (3.2 g, 0.05 mol). The reaction mixture was stirred for 24 h at room temperature before water (100 mL) was added to quench the reaction. Finally, the suspension was extracted three times with diethyl ether. The organic layers were combined and washed with brine, followed by addition of MgSO4 for drying. The solution was finally concentrated under vacuum to yield the final product as slight yellow oil (3.85 g, 90%). ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ3.66- 3.24 (m, 4H, -C2H4OH), 1.69-1.61 (m, 4H, -C2H4N3), 1.44-1.23 (m, 14H, -C7H14-). 1.2 Synthesis of 11-azidoundecyl 3-hydroxy-2-(hydroxymethyl)-2- methylpropanoate (with two hydroxyl groups, Initiator 2)

11-Azido-undecanol (Initiator 1, 0.35, 1.65 mmol) was stirred with 2,2,5-trimethyl-1,3- dioxane-5-carboxylic anhydride (1.54g, 9.93 mmol), pyridine (3.77 ml, 33.1 mmol) and DMAP (88 mg, 0.72 mmol) over 2 days at room temperature in dichloromethane. The product was purified with flash chromatography with an eluent of 20% ethyl acetate/hexane. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ4.31-4.12 (m, 4H, 2 X -OCH2CC2- ), 3.65-3.24 (m, 4H, -C2H ₄ OCO-), 1.68-1.53 (m, 4H, -C2H ₄ N3), 1.48-1.27 (m, 20H, - C7H14- and–O2C(CH3)2), 1.20 (s, -CH3). The azide-containing initiator with two hydroxyl groups was finally obtained by mixing the purified product with Amberlyst® 15 under reflux with stirring in ethanol overnight. The final product was obtained by drying under vacuum. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ4.18-3.24 (m, 4H, 2 X -OCH ₂ CC2- and -C2H ₄ OCO-), 1.68-1.69 (m, 4H, - C2H ₄ N3), 1.48-1.27 (m, 14H, -C7H ₁₄ -), 1.20 (s, -CH3). 1.3 Synthesis of 11-azidoundecyl 3-hydroxy-2-(((3-hydroxy-2-(hydroxymethyl)- 2-methylpropanoyl)oxy)methyl)-2-methylpropanoate (with three hydroxyl

The initiator with two hydroxyl groups (Initiator 2) was stirred with 2,2,5-trimethyl-1,3- dioxane-5-carboxylic anhydride, pyridine and DMAP over 2 days at room temperature in dichloromethane. The product was purified with flash chromatography with an eluent of 10% ethyl acetate/dichloromethane. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ5.74-5.83 (m, 1H, -OH), 4.33-3.65 (m, 8H, 4 X -OCH2CC2-), 2.00-1.64 (m, 34H, -C2H4OCO-, - C2H4N3, -C7H14-. -O2C(CH3)2, 2 X -CH3). The initiator with three hydroxyl groups was finally obtained by mixing the purified product with Amberlyst® 15 under reflux with stirring in ethanol overnight. The final product was obtained by drying under vacuum. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ5.78-5.82 (m, 3H, 3 X -OH), 4.35-3.67 (m, 8H, 4 X -OCH2CC2-), 2.05-1.60 (m, 28H, -C2H ₄ OCO-, -C2H ₄ N3, -C7H ₁₄ -. -O2C(CH ₃ )2, 2 X -CH3).

n a ry wo-nec m roun o om ask equipped with a stir bar, MTC-OH (3.08 g, 19.3 mmol) was first dissolved in dry THF (50 mL) with 5-8 drops of dimethylformamide (DMF). Subsequently, oxalyl chloride (3.3 mL) was added in one shot (pure form), followed by an additional 20 mL of THF. The solution was stirred for 90 min, after which volatiles were blown dry under a strong flow of nitrogen to yield a pale yellow solid intermediate ( 5-chlorocarboxy-5-methyl-1,3-dioxan-2-one, MTC-Cl). The solid was then subjected to heat at 60 °C for 2-3 min for the removal of residual solvent, re-dissolved in dry dichloromethane (DCM, 50 mL), followed by immersed in the flask in an ice bath at 0 °C. A mixture of para-chloromethylbenzyl alcohol (2.79 g, 17.8 mmol) and pyridine (1.55 mL, 19.3 mmol) were dissolved in dry DCM (50 mL), which was added dropwise to the flask over a duration of 30 min, and allowed to stir at room temperature (~ 22 ºC) for an additional 2.5 h after complete addition. The reacted mixture was quenched by addition of 50 mL of brine, and the organic solvent was collected after separation. After removal of solvent, the crude product was purified by silica-gel flash column chromatography through a hexane-ethyl acetate solvent system (gradient elution up to 80% vol. ethyl acetate) to yield MTC-OCH2BnCl as a white solid. The crude product was further purified by recrystallization. The solid was dissolved in 1 mL of DCM and ethyl acetate, followed by addition of 50 mL of diethyl ether. The crystals were allowed to form at 0 °C for 2 days, and were subsequently obtained by washing the crystals with cold diethyl ether. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.37 (dd, J = 20.2, 8 Hz, 4H, Ph-H), 5.21 (s, 2H, -OCH2), 4.69 (d, J = 13.6 Hz, 2H, -OCH2C-), 4.59 (s, 2H, -CH2Cl), 4.22 (d, J = 14.8 Hz, 2H, -OCH2C-), 1.32 (s, 3H, -C2CH3). Example 3: Synthesis of furan-protected maleimide-functionalized carbonate protected maleimide cyclic carbonate monomer (MTC-FPM)

MTC-OCH2BnCl was synthesized as described above, and re-dissolved in dry DCM (50 mL), followed by immersed in the flask in an ice bath at 0 °C. A mixture of exo- 3a,4,7,7a-tetrahydro-2-(3-hydroxypropyl)-4,7-epoxy-1H-isoind ole-1,3(2H)-dione (3.97 g, 17.8 mmol) and triethylamine (1.77 mL, 19.3 mmol) were dissolved in dry DCM (50 mL), which was added dropwise to the flask over a duration of 30 min, and allowed to stir at room temperature for an additional 24 h after complete addition. The reacted mixture was quenched by addition of 50 mL of water, and the organic solvent was collected after separation. After removal of solvent, the crude product was dissolved in 4 mL of DCM, followed by addition of 50 mL of diethyl ether for recrystallization. The crystals were allowed to form at room temperature, and were subsequently obtained by washing with cold diethyl ether. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 6.51 (s, 2H, - CH = CH), 5.25 (s, 2H, -OCHC2-), 4.74 (d, 2H, J = 14.4 Hz, -OCH2CC2-), 4.22 (d, 2H, J = 14.8 Hz, -OCH ₂ CC2-), 4.11 (t, 2H, J = 6.0 Hz, -OCH ₂ CH2-), 3.58 (t, 2H, J = 6.6 Hz, CH2CH2NC-), 2.85 (s, 2H, -COCHC-), 1.96 (quin, 6.4 Hz, 2H, -CONCCOCHC-), 1.38 (s, 3H, -C2CH3). Example 4: Synthesis of an alkyne-functionalized carbonate monomer (MTC-≡, MTC-

MTC-OCH2BnCl was synthesized as described above, and re-dissolved in dry DCM (50 mL), followed by immersed in the flask in an ice bath at 0 °C. A mixture of propargyl alcohol (1 g, 17.8 mmol) and triethylamine (1.77 mL, 19.3 mmol) were dissolved in dry DCM (50 mL), which was added dropwise to the flask over a duration of 30 min, and allowed to stir at room temperature (~ 22 ºC) for an additional 2.5 h after complete addition. The reacted mixture was quenched by addition of 50 mL of brine, and the organic solvent was collected after separation. After removal of solvent, the crude product was purified by silica-gel flash column chromatography through a hexane- ethyl acetate solvent system (gradient elution up to 50% vol. ethyl acetate) to yield MTC-OCH2C≡CH (MTC-≡, MTC-alkyne) as a white solid. The crude product was further purified by recrystallization. The solid was dissolved in 1 mL of DCM, followed by addition of 50 mL of diethyl ether. The crystals were allowed to form at room temperature, and were subsequently obtained by washing the crystals with cold diethyl ether. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ4.80 (d, J = 2.4 Hz, 2H, -OCH2C≡CH), 4.72 (d, J = 10.8 Hz, 2H, -OCH2CC2-), 4.24 (d, J = 10.8 Hz, 2H, -OCH2CC2-), 2.55 (t, J = 2.4 Hz, 1H, OCH2C≡CH), 1.38 (s, 3H, -CH3). Example 5: Polymer synthesis 5.1 Synthesis of alkyne- and maleimide-functionalized polycarbonates and alkyne-functionalized diblock copolymers of PEG and maleimide/alkyne- functionalized polycarbonate for the first layer of coating

re synthesized from OROP of MTC-FPM synthesized in Example 3 at varying DP using propargyl alcohol (containing an alkyne group) as an initiator. In addition, polymers 1d and 1e containing PEG were synthesized from OROP of MTC-FPM synthesized in Example 3 and an alkyne-functionalized carbonate monomer synthesized in Example 4 using MPEG (164 Da and 2.4 kDa) as a macroinitiator. The protected maleimide moieties were subsequently deprotected. ¹ H NMR integration values of monomers against the anomeric protons of propargyl alcohol or the protons from MPEG were correlated, confirming controlled polymerization based on monomer to initiator feed ratio (Table 1).

Table 1. Compositions and molecular weights (Mn) of alkyne- and maleimide-

In addition, the ¹ H NMR analysis displayed all the peaks associated with both initiator and monomers. All polymers had narrow molecular weight distribution with polydispersity index (PDI) ranging between 1.18 and 1.29 (Figure 1 and Table 1). The 1H NMR spectra of the deprotected polymers showed a downfield shift from 6.49 to 6.68 ppm, correlating to the deprotected maleimide pendant groups. Polymer compositions and PDI values were similar before and after deprotection (Table 1), indicating that the deprotection did not affect the polymer chain significantly.

1

1

Details of OROP for polymer 1d are given as an example of the polymers used as the first coating layer. In a glove-box, 43.8 mg (0.027 mmol) of MPEG-OH (164 Da, MPEG164-OH) as initiator and 0.2 g (0.55 mmol) of MTC-FPM were charged in a 20 mL glass vial equipped with a stir bar. DCM was added and the monomer concentration was adjusted to 2 M. Once the initiator and monomer were completely dissolved, 4.9 µL (0.036 mmol) of DBU was added to initiate the polymerization. After 3.5 hours, 30 mg (0.27 mmol) of MTC-≡ monomer were added to the reaction mixture. The reaction proceeded at room temperature under stirring for another 40 min before it was quenched with 30 µL of trifluoroacetic acid. Subsequently, the polymer intermediate was purified via precipitation twice in cold diethyl ether, and was dried on a vacuum line until a constant weight was achieved. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 6.53-6.48 (m, 34H, -CHOC2H4CHO-), 4.72-4.67 (m, 10H, -COOCH2C≡CH), 4.47- 4.23 (m, 88H, -COOCH2-), 4.14-4.03 (m, 34H, -COOCH2CH2-), 3.78-3.61 (m, 12H, - (OCH2)2CH2), 3.59-3.51 (m, 34H, -CH2CH2NR2), 2.88-2.83 (m, 34H, -CC2HCC2H-), 2.58-2.51 (m, 5H, -COOCH2C≡CH), 1.98-1.86 (m, 32H, -OCH2CH2CH2-), 1.35-1.20 (m, 66H, -CH3). The protected polymer 1d was then deprotected by dissolving in 10 mL of toluene and heated to 110 °C overnight. After that, the toluene was removed under vacuum and the deprotected polymer was dissolved in 2 mL of DCM and precipitated in cold diethyl ether. Polymer 1d was subsequently dried on a vacuum line until a constant weight was achieved. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 6.74-6.68 (m, 30H, - CHOC2H4CHO-), 4.73-4.68 (m, 6H, -COOCH2C≡CH), 4.48-4.23 (m, 72H, -COOCH2- ), 4.14-4.03 (m, 30H, -COOCH2CH2-), 3.80-3.68 (m, 12H, -(OCH2)2CH2), 3.64-3.53 (m, 30H, -CH2CH2NR2), 2.58-2.51 (m, 3H, -COOCH2C≡CH), 1.99-1.88 (m, 30H, - OCH2CH2CH2-), 1.35-1.20 (m, 60H, -CH3).

Similarly, polymers 1a, 1b, 1c and 1e were synthesized using propargyl alcohol as initiator. Polymer 1e was synthesized using a longer PEG as initiator (2.4 kDa, MPEG2.4k-OH). As for polymers 1a, 1b and 1c, the monomer MTC-≡ was not added to the reaction mixture. The feed molar ratio of MTC-FPM:MTC-Alkyne:Initiator for the synthesis of polymers 1a to 1e are provided in Table 1.

1H NMR (400 MHz, CDCl3, 22 ºC): δ 6.53-6.46 (m, 16H, -CHOC2H4CHO-), 5.28-5.21 (m, 16H, -R2CHOCHR2-), 4.78-4.71 (m, 2H, -COOCH2C≡CH), 4.49-4.20 (m, 32H, - CH2OCOO-), 4.16-4.02 (m, 16H, -COOCH2CH2-), 3.65-3.45 (m, 16H, -CH2CH2NR2), 2.89-2.81 (m, 16H, -CC2HCC2H-), 2.01-1.89 (m, 16H, -OCH2CH2CH2-), 1.43-1.25 (m, 24H, -CH3). Polymer 1a

1H NMR (400 MHz, CDCl3, 22 ºC): δ ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 6.75-6.70 (m, 12H, -CHOC2H4CHO-), 4.72-4.67 (m, 2H, -COOCH2C≡CH), 4.49-4.20 (m, 12H, - COOCH2-), 4.15-4.06 (m, 24H, -COOCH2CH2-), 3.65-3.56 (m, 12H, -CH2CH2NR2), 2.59-2.52 (m, 1H, -COOCH2C≡CH), 2.02-1.88 (m, 12H, -OCH2CH2CH2-), 1.36-1.19 (m, 18H, -CH3). Polymer 1b (protected/prot)

1H NMR (400 MHz, CDCl3, 22 ºC): δ 6.54-6.47 (m, 40H, -CHOC2H4CHO-), 5.27-5.19 (m, 40H, -R2CHOCHR2-), 4.74-4.71 (m, 2H, -COOCH2C≡CH), 4.46-4.25 (m, 80H, - CH ₂ OCOO-), 4.12-4.03 (m, 40H, -COOCH2CH2-), 3.60-3.51 (m, 20H, -CH2CH2NR2), 2.86-2.82 (m, 20H, -CC2HCC2H-), 1.98-1.88 (m, 20H, -OCH2CH2CH2-), 1.35-1.20 (m, 60H, -CH3). Polymer 1b

1H NMR (400 MHz, CDCl3, 22 ºC): δ 6.74-6.70 (m, 30H, -CHOC2H4CHO-), 4.72-4.70 (m, 2H, -COOCH2C≡CH), 4.47-4.23 (m, 30H, -COOCH2-), 4.18-4.06 (m, 60H, - COOCH2CH2-), 3.65-3.52 (m, 30H, -CH2CH2NR2), 2.57-2.53 (m, 1H, - COOCH2C≡CH), 1.98-1.89 (m, 30H, -OCH2CH2CH2-), 1.33-1.15 (m, 45H, -CH3). Polymer 1c (protected/prot)

1H NMR (400 MHz, CDCl3, 22 ºC): δ H NMR (400 MHz, CDCl3, 22 ºC): δ 6.54-6.46 (m, 70H, -CHOC2H4CHO-), 5.26-5.19 (m, 70H, -R2CHOCHR2-), 4.73-4.71 (m, 2H, - COOCH2C≡CH), 4.46-4.22 (m, 140H, -CH2OCOO-), 4.15-4.02 (m, 70H, - COOCH2CH2-), 3.62-3.55 (m, 70H, -CH2CH2NR2), 2.89-2.82 (m, 70H, -CC2HCC2H-), 1.98-1.85 (m, 70H, -OCH2CH2CH2-), 1.37-1.19 (m, 105H, -CH3). Polymer 1c

1H NMR (400 MHz, CDCl3, 22 ºC): δ 6.73-6.69 (m, 68H, -CHOC2H4CHO-), 4.73-4.68 (m, 2H, -COOCH2C≡CH), 4.48-4.21 (m, 136H, -COOCH2-), 4.14-4.05 (m, 68H, - COOCH2CH2-), 3.63-3.55 (m, 68H, -CH2CH2NR2), 2.58-2.51 (m, 1H, - COOCH2C≡CH), 2.00-1.88 (m, 68H, -OCH2CH2CH2-), 1.35-1.20 (m, 102H, -CH3). Polymer 1e (protected/prot)

1H NMR (400 MHz, CDCl3, 22 ºC): δ 76.74-6.68 (m, 20H, -CHOC2H4CHO-), 4.74-4.69 (m, 8H, -COOCH2C≡CH), 4.50-4.25 (m, 56H, -COOCH2-), 4.12-4.04 (m, 20H, - COOCH2CH2-), 3.87-3.56 (m, 217H, -OCH2CH2- from 2.4kDa MPEG), 3.57-3.46 (m, 20H, -CH2CH2NR2), 2.95-2.87 (m, 20H, -CC2HCC2H-), 2.54-2.50 (m, 4H, - COOCH2C≡CH), 2.05-1.96 (m, 20H, -OCH2CH2CH2-), 1.40-1.15 (m, 42H, -CH3). Polymer 1e

1H NMR (400 MHz, CDCl3, 22 ºC): δ 6.73-6.69 (m, 16H, -CHOC2H4CHO-), 4.75-4.68 (m, 6H, -COOCH2C≡CH), 4.46-4.22 (m, 44H, -COOCH2-), 4.14-4.05 (m, 16H, - COOCH2CH2-), 3.84-3.55 (m, 217H, -OCH2CH2- from 2.4kDa MPEG), 3.53-3.45 (m, 16H, -CH2CH2NR2), 2.53-2.51 (m, 3H, -COOCH2C≡CH), 2.03-1.95 (m, 16H, - OCH2CH2CH2-), 1.40-1.15 (m, 33H, -CH3). 5.2 Synthesis of azide-functionalized cationic polycarbonates with different architecture for the second layer of coating

azide-con anng n a ors syn esze n xampe . These polymers also had narrow PDI ranging from 1.19 to 1.29 (Figure 1c and Table 2). After quaternization with a tertiary amine such as dimethylbutylamine or dimethyloctylamine, a new distinct peak appeared at 2.99 ppm in the ¹ H NMR spectra, confirming that quaternization of benzyl chloride pendant groups took place (Figure 2).

y g p y y Details of OROP for the cationic polymers (2b’, 2b”) as the second coating layer are given as an example. In a glove-box, 2.5 mg (0.012 mmol) of N3-C11-OH initiator and 0.21 g (0.70 mmol) of MTC-CH2OBnCl were charged in a 20 mL glass vial equipped with a stir bar. DCM was added and the monomer concentration was adjusted to 2 M. Once the initiator and monomer were completely dissolved, 5.3 µL (0.040 mmol) of DBU and 13 mg (0.040 mmol) of TU were added to initiate the polymerization. The reaction proceeded at room temperature under stirring for 20 min before it was quenched with 20 µL of trifluoroacetic acid. Subsequently, the polymer intermediate 2b was purified via precipitation twice in cold methanol, and was dried on a vacuum line until a constant weight was achieved. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.41-7.26 (m, 180H,-C6H4CH2Cl), 5.16-5.08 (m, 90H, -C6H4CH2Cl), 4.58-4.53 (m, 90H, -COOCH2-), 4.45-4.16 (m, 180H, -CH2OCOO- ), 4.08-4.03 (m, 2H, -RCH2OH), 3.75-3.67 (m 4H, -RCH2CH2CH2OH), 3.25-3.21 (m, 2H, -RCH2N3), 1.38-1.19 (m, 149H, -CH3 and N3CH2(CH2)8CH2CH2OH). The polymer was dissolved in 20 mL of acetonitrile, and an excess (2 mL) of N,N- dimethylbutylamine (for polymer 2b’) or N,N-dimethyloctylamine (for polymer 2b”) was added to fully quaternize the OBnCl pendant groups in polymer 2b. The reaction mixture was stirred overnight in a 50 mL round bottom flask at room temperature, and the solvent was then removed in vacuo. The obtained product was dissolved in a mixture of acetonitrile and isopropanol (1:1 in volume), and dialyzed against the solvent mixture for 2 days. The solvent was removed under reduced pressure, and the final product was dried in a vacuum oven until a constant mass was achieved. Polymer 2b’: ¹ H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.63-7.21 (m, 160H,-C6H4CH2Cl), 5.40-5.03 (m 80H, -C6H4CH2Cl), 4.73-4.56 (m, 80H, -COOCH2-), 4.45-4.15 (m, 160H, -CH2OCOO-), 4.05-4.00 (m, 2H, -RCH2O-), 3.58-3.42 (m, 4H, -RCH2CH2CH2O-), 3.35- 3.23 (m, 80H, -N ⁺ CH2C3H7), 3.18-3.14 (m, 2H, -RCH2N3), 3.09-2.87 (m, 240H, - N ⁺ [CH3]2), 1.86-1.68 (m, 80H, -N ⁺ CH2CH2C2H5), 1.38-1.03 (m, 200H, - N ⁺ CH2CH2C2H5), 0.97-0.86 (m, 134H, -CH3 and R(CH2)7CH2CH2O-). Polymer 2b”: ¹ H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.63-7.20 (m, 156H,-C6H4CH2Cl), 5.35-5.08 (m, 78H, -C6H4CH2Cl), 4.72-4.48 (m, 78H, -COOCH2-), 4.48-4.18 (m, 156H, -CH ₂ OCOO-), 4.04-4.01 (m, 2H, -RCH2O-), 3.56-3.38 (m, 4H, -RCH2CH2CH2OH), 3.37-3.20 (m, 78H, -N ⁺ CH2C7H15), 3.19-3.15 (m, 2H, -RCH2N3), 3.08-2.88 (m, 240H, - N ⁺ [CH3]2-), 1.85-1.69 (m, 78H, -N ⁺ CH2CH2C6H13), 1.45-1.04 (m, 507H, - N ⁺ CH2CH2C6H13), 0.95-0.79 (m, 131H, -CH3 and R(CH2)7CH2CH2O-). Similarly, polymers 2a, 2c, 2d and 2e and their quaternized derivatives were synthesized. Polymers 2d, 2e and 2f were synthesized using azide-containing initiators having two and three hydroxyl groups (i.e. Initiator 2 from Example 1.2 and Initiator 3 from Example 1.3, respectively), while polymers 2a and 2c had a varying degree of polymerization of benzyl chloride moieties when compared to polymer 2b, and azide-containing initiator having one hydroxyl group (i.e. Initiator 1 from Example 1.1). Polymer 2a

1H NMR (400 MHz, CDCl3, 22 ºC) 7.39-7.26 (m, 100H,-C6H4CH2Cl), 5.17-5.08 (m, 50H, -C6H4CH2Cl), 4.53-4.47 (m, 50H, -COOCH2-), 4.43-4.24 (m, 100H, -CH ₂ OCOO- ), 4.10-4.06 (m, 2H, -RCH2O-), 3.75-3.67 (m 4H, -RCH2CH2CH2O-), 3.26-3.21 (m, 2H, -RCH2N3), 1.39-1.19 (m, 91H, -CH3 and R(CH2)8CH2CH2O-) Polymer 2a’

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.67-7.21 (m, 88H,-C6H4CH2Cl), 5.40-5.03 (m 44H, -C6H4CH2Cl), 4.73-4.52 (m, 44H, -COOCH2-), 4.45-4.15 (m, 88H, -CH2OCOO-), 4.08-3.97 (m, 2H, -RCH2O-), 3.58-3.43 (m, 4H, -RCH2CH2CH2O-), 3.33-3.24 (m, 44H, -N ⁺ CH2C3H7), 3.18-3.14 (m, 4H, -RCH2CH2N3), 3.08-2.78 (m, 134H, -N ⁺ [CH3]2- and - RCH2N3), 1.87-1.69 (m, 44H, -N ⁺ CH2CH2C2H5), 1.40-1.11 (m, 110H, - N ⁺ CH2CH2C2H5), 0.97-0.83 (m, 76H, -CH3 and R(CH2)5CH2CH2O-). Polymer 2a”

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.64-7.20 (m, 88H,-C6H4CH2Cl), 5.37-5.08 (m, 44H, -C6H4CH2Cl), 4.70-4.49 (m, 44H, -COOCH2-), 4.49-4.20 (m, 88H, -CH2OCOO-), 4.04-4.00 (m, 2H, -RCH2O-), 3.57-3.39 (m, 4H, -RCH2CH2CH2OH), 3.38-3.21 (m, 44H, -N ⁺ CH2C7H15), 3.20-3.15 (m, 2H, -RCH2N3), 3.13-2.89 (m, 132H, -N ⁺ [CH3]2-), 1.88- 1.69 (m, 44H, -N ⁺ CH2CH2C6H13), 1.45-1.03 (m, 110H, -N ⁺ CH2CH2C6H13), 0.96-0.78 (m, 80H, -CH3 and R(CH2)7CH2CH2O-). Polymer 2c

1H NMR (400 MHz, CDCl3, 22 ºC) 7.39-7.25 (m, 336H,-C6H4CH2Cl), 5.18-5.07 (m, 168H, -C6H4CH2Cl), 4.58-4.52 (m, 168H, -COOCH2-), 4.48-4.18 (m, 336H, - CH ₂ OCOO-), 4.10-4.05 (m, 2H, -RCH2O-), 3.76-3.67 (m, 4H, -RCH2CH2CH2OH), 3.27-3.20 (m, 2H, -RCH2N3), 1.38-1.19 (m, 266H, -CH3 and N3CH2(CH2)8CH2CH2O-) Polymer 2c’

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.62-7.20 (m, 320H,-C6H4CH2Cl), 5.38-5.04 (m, 160H, -C6H4CH2Cl), 4.72-4.55 (m, 160H, -COOCH2-), 4.40-4.13 (m, 320H, - CH2OCOO-), 4.06-4.00 (m, 2H, -RCH2O-), 3.57-3.48 (m, 4H, -RCH2CH2CH2OH), 3.36-3.22 (m, 160H, -N ⁺ CH2C3H7), 3.17-3.13 (m, 4H, -RCH2CH2N3), 3.08-2.79 (m, 480H, -N ⁺ [CH3]2), 1.84-1.65 (m, 160H, -N ⁺ CH2CH2C2H5), 1.38-1.03 (m, 400H, - N ⁺ CH2CH2C2H5), 0.98-0.88 (m, 240H, -CH3). Polymer 2d (2-arm)

1H NMR (400 MHz, CDCl3, 22 ºC) 7.52-7.25 (m, 208H,-C6H4CH2Cl), 5.18-5.11 (m, 104H, -C6H4CH2Cl), 4.58-4.51 (m, 104H, -COOCH2-), 4.47-4.16 (m, 208H, - CH2OCOO-), 4.11-4.08 (m, 2H, -RCH2OCO-), 3.75-3.68 (m, 4H, -OCOC(CH3)CH2-), 3.26-3.20 (m, 2H, -RCH2N3), 1.38-1.19 (m, 177H, -CH3, -CH3 from initiator and N3CH2(CH2)9CH2O-) Polymer 2d’ (2-arm, dimethylbutylamine quaternized)

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.63-7.21 (m, 192H,-C6H4CH2Cl), 5.40-5.03 (m, 96H, -C6H4CH2Cl), 4.73-4.57 (m, 96H, -COOCH2-), 4.42-4.18 (m, 192H, -CH ₂ OCOO- ), 4.02-3.97 (m, 2H, -RCH2OCO-), 3.59-3.52 (m, 4H, -OCOC(CH3)CH2-), 3.51-3.42 (m, 4H, -RCH2CH2CH2O-), 3.38-3.23 (m, 96H, -N ⁺ CH2C3H7), 3.18-3.13 (m, 4H, - RCH2CH2N3), 3.10-2.80 (m, 288H, -N ⁺ [CH3]2), 1.83-1.68 (m, 96H, -N ⁺ CH2CH2C2H5), 1.38-1.02 (m, 240H, -N ⁺ CH2CH2C2H5), 0.98-0.88 (m, 162H, -CH3, -CH3 from initiator and N3CH2CH2(CH2)6R). Polymer 2d” (2-arm, dimethyloctylamine quaternized)

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.62-7.19 (m, 200H,-C6H4CH2Cl), 5.23-5.05 (m, 100H, -C6H4CH2Cl), 4.78-4.48 (m, 100H, -COOCH2-), 4.45-4.98 (m, 200H, - CH ₂ OCOO-), 4.05-4.00 (m, 2H, -RCH2O-), 3.58-3.50 (m, 4H, -OCOC(CH3)CH2-), 3.49- 3.42 (m, 4H, -RCH2CH2CH2O-), 3.34-3.18 (m, 100H, -N ⁺ CH2C3H7), 3.15-3.10 (m, 4H, -RCH2CH2N3), 3.05-2.82 (m, 300H, -N ⁺ [CH3]2), 1.84-1.65 (m, 100H, - N ⁺ CH2CH2C6H13), 1.39-0.98 (m, 650H, -N ⁺ CH2CH2C6H13), 0.95-0.70 (m, 165H, -CH3 , -CH3 from initiator and N3CH2CH2(CH2)6R). Polymer 2e (2-arm)

1H NMR (400 MHz, CDCl3, 22 ºC) 7.41-7.27 (m, 400H,-C6H4CH2Cl), 5.17-5.11 (m, 200H, -C6H4CH2Cl), 4.58-4.53 (m, 200H, -COOCH2-), 4.48-4.14 (m, 400H, - CH2OCOO-), 4.11-4.09 (m, 2H, -RCH2OCO-), 3.74-3.67 (m, 4H, -OCOC(CH3)CH2-), 3.26-3.22 (m, 2H, -RCH2N3), 1.40-1.19 (m, 321H, -CH3, -CH3 from initiator and N3CH2(CH2)9CH2O-) Polymer 2e’ (2-arm, dimethylbutylamine quaternized)

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.62-7.21 (m, 400H,-C6H4CH2Cl), 5.40-5.01 (m, 200H, -C6H4CH2Cl), 4.74-4.55 (m, 200H, -COOCH2-), 4.39-4.16 (m, 400H, - CH ₂ OCOO-), 4.01-3.98 (m, 2H, -RCH2O-), 3.59-3.53 (m, 4H, -OCOC(CH3)CH2-), 3.51- 3.44 (m, 4H, -RCH2CH2CH2O-), 3.37-3.23 (m, 200H, -N ⁺ CH2C3H7), 3.19-3.13 (m, 4H, -RCH2CH2N3), 3.11-2.83 (m, 600H, -N ⁺ [CH3]2), 1.81-1.68 (m, 200H, -N ⁺ CH2CH2C2H5), 1.35-1.03 (m, 500H, -N ⁺ CH2CH2C2H5), 0.98-0.87 (m, 315H, -CH3, -CH3 from initiator and N3CH2CH2(CH2)6R). Polymer 2e” (2-arm, dimethyloctylamine quaternized)

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.63-7.21 (m, 368H,-C6H4CH2Cl), 5.39-5.06 (m, 184H, -C6H4CH2Cl), 4.71-4.53 (m, 184H, -COOCH2-), 4.43-4.16 (m, 368H, - CH2OCOO-), 4.03-3.99 (m, 2H, -RCH2O-), 3.58-3.54 (m, 4H, -OCOC(CH3)CH2-), 3.53- 3.47 (m, 4H, -RCH2CH2CH2O-), 3.35-3.21 (m, 184H, -N ⁺ CH2C3H7), 3.19-3.15 (m, 4H, -RCH2CH2N3), 3.12-2.86 (m, 552H, -N ⁺ [CH3]2), 1.83-1.69 (m, 184H, - N ⁺ CH2CH2C6H13), 1.34-1.02 (m, 1196H, -N ⁺ CH2CH2C6H13), 0.99-0.78 (m, 291H, -CH3 and , -CH3 from initiator and N3CH2CH2(CH2)6R). Polymer 2f (3-arm)

1H NMR (400 MHz, CDCl3, 22 ºC) 7.40-7.23 (m, 204H,-C6H4CH2Cl), 5.17-5.09 (m, 102H, -C6H4CH2Cl), 4.59-4.51 (m, 102H, -COOCH2-), 4.47-4.18 (m, 204H, - CH ₂ OCOO-), 3.75-3.67 (m, 8H, -OCOC(CH3)CH2- and -OCOC(CH3)CH2- from Gen 0 and 1), 1.38-1.19 (m, 181H, -CH3, N3(CH2)11O- and 2 X–CH3 from Gen 0 and 1) Polymer 2f” (3-arm, dimethyloctylamine quaternized)

1H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.63-7.18 (m, 204H,-C6H4CH2Cl), 5.38-5.02 (m, 102H, -C6H4CH2Cl), 4.72-4.51 (m, 102H, -COOCH2-), 4.42-4.18 (m, 204H, - CH2OCOO-), 3.60-3.52 (m, 8H, -OCOC(CH3)CH2- and -OCOC(CH3)CH2- from Gen 0 and 1), 3.35-3.21 (m, 102H, -N ⁺ CH2C3H7), 3.11-2.85 (m, 306H, -N ⁺ [CH3]2), 1.83-1.68 (m, 102H, -N ⁺ CH2CH2C6H13), 1.38-1.03 (m, 663H, -N ⁺ CH2CH2C6H13), 0.93-0.78 (m, 181H, -CH3, N3(CH2)11O- and 2 X–CH3 from Gen 0 and 1). 5.3 Synthesis of alkyne-containing maleimide-functionalized cationic diblock copolymer 1f (protected) ([P(FPM)-P(BnCl), protected])

(0.41 mmol) of MTC-FPM were charged in a 20 mL glass vial equipped with a stir bar. DCM was added and the monomer concentration was adjusted to 2 M. Once the initiator and monomer were completely dissolved, 3.7 µL (0.025 mmol) of DBU was added to initiate the polymerization. The reaction proceeded at room temperature under stirring for 3.5 h, and subsequently, 0.4 g of MTC-OCH2BnCl were added to the reaction mixture, and followed by addition of 6.3 µL (0.042 mmol) of DBU and 24.7 mg (0.067 mmol) of TU. The reaction proceeded at room temperature under stirring for another 35 min before it was quenched with 30 µL of trifluoroacetic acid. Subsequently, the polymer intermediate [P(FPM)-P(BnCl), protected] was purified through precipitation twice in cold diethyl ether, and was dried on a vacuum line until a constant weight was achieved. Polymer 1f (protected): ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.42-7.27 (m, 136H, -C6H4CH2Cl), 6.53-6.46 (m, 32H, -CHOC2H4CHO-), 5.28-5.20 (m, 32H, -R2CHOCHR2-), 5.17-5.06 (m, 156H, -COOCH2-), 4.73-4.70 (m, 2H, HC≡CCH2R-), 4.62-4.52 (m, 156H, -C6H4CH2Cl), 4.47-4.18 (m, 136H, -CH2OCOO-), 4.16-4.02 (m, 32H, -COOCH2CH2-), 3.60-3.43 (m, 32H, -CH2CH2NR2), 2.88-2.80 (m, 32H, -CC2HCC2H-), 1.98-1.88 (m, 32H, -OCH2CH2CH2-), 1.38-1.18 (m, 234H, -CH3). PDI:1.17. Polymer 1f (PM-P(BnCl))

The protected polymer was then deprotected by dissolving in 10 mL of toluene and heated to 110 °C overnight. After that, the toluene was removed under vacuum and the deprotected polymer was dissolved in 2 mL of DCM and precipitated in cold diethyl ether. The deprotected polymer PM-P(BnCl) (polymer 1f) was subsequently dried on a vacuum line until a constant weight was achieved. ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.38-7.27 (m, 120H, -C6H4CH2Cl), 6.67-6.73 (m, 28H, -COC2H4CO-), 5.19-5.09 (m, 60H, -COOCH2-), 4.73-4.70 (m, 2H, C≡CCH2R-), 4.59-4.54 (m, 60H, -C6H4CH2Cl), 4.46-4.23 (m, 176H, -CH2OCOO-), 4.13-4.02 (m, 28H, -COOCH2CH2-), 3.78-3.52 (m, 28H, -CH2CH2NR2), 1.98-1.88 (m, 28H, -OCH2CH2CH2-), 1.36-1.20 (m, 132H, -CH3). PDI: 1.18 Polymer 1f’ (dimethylbutylamine quaternized)

, , - dimethylbutylamine was added to fully quaternize the OBnCl pendant groups. The reaction mixture was stirred overnight in a 50 mL round bottom flask at room temperature, and the solvent was then removed in vacuo. The resulting product was dissolved in a mixture of acetonitrile and isopropanol (1:1 in volume), and dialyzed against the solvent mixture for 2 days. The solvent was removed under reduced pressure, and the final product polymer 1f’ was dried in a vacuum oven until a constant mass was achieved. ¹ H NMR (400 MHz, (CD3)2CO, 22 ºC) 7.69-7.38 (m, 116H,- C6H4CH2Cl), 7.22-6.43 (m, 26H, -COC2H4CO-), 5.28-5.21 (m, 58H, -COOCH2-), 5.18- 5.05 (m, 26H, -COOCH2CH2-), 4.88-4.82 (m, 2H, C≡CCH2R-), 4.79-4.48 (m, 58H, - C6H4CH2Cl), 4.45-4.00 (m, 168H, -CH ₂ OCOO-), 3.55-3.48 (m, 26H, -CH2CH2NR2), 3.36-3.21 (m, 26H, -N ⁺ CH2C3H7), 2.98 (s, 174H, -N ⁺ [CH3]2-), 2.26-2.08 (m, 26H, - OCH2CH2CH2-), 1.98-1.68 (m, 26H, -N ⁺ CH2CH2C2H5), 1.45-1.10 (m, 65H, - N ⁺ CH2CH2C2H5), 0.98-0.82 (m, 126H, -CH3). 5.4 Synthesis of diblock copolymer of PEG and benzyl chloride-functionalized polycarbonate (2g and 2h) and azide-functionalized polycarbonate and PEG diblock copolymer (2g ^# and 2h ^# )

In a glove-box, 2.5 mg (0.13 mmol) of short MPEG (MPEG 164-OH, MW = 164 Da) initiator and 0.20 g (0.67 mmol) of MTC-CH2OBnCl were charged in a 20 mL glass vial equipped with a stir bar. DCM was added and the monomer concentration was adjusted to 2 M. Once the initiator and monomer were completely dissolved, 5.0 µL (0.033 mmol) of DBU and 12.4 mg (0.033 mmol) of TU were added to initiate the polymerization. The reaction proceeded at room temperature under stirring for a precise 20 min before it was quenched with 20 µL of trifluoroacetic acid. Subsequently, the polymer intermediate was purified via precipitation twice in cold methanol, and was dried on a vacuum line until a constant weight was achieved. Polymer 2g: ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.37-7.26 (m, 40H, -C6H4CH2Cl), 5.18-5.08 (m, 20H, - CHOC2H4CHO-), 4.61-4.55 (m, 20H, -R2CHOCHR2-), 4.44-4.23 (m, 40H, -CH ₂ OCOO- ), 3.70-3.51 (m, 13H, -OCH2CH2- from 2.4kDa MPEG), 1.32-1.19 (m, 30H, -CH3). Polymer 2h was synthesized in the same fashion as polymer 2g, using a longer PEG initiator (MPEG2.4k-OH, MW =2.4 kDa) while keeping the degree of polymerization of MTC-CH2OBnCl constant. Polymer 2h:

1H NMR (400 MHz, CDCl3, 22 ºC): δ 7.37-7.26 (m, 20H, -C6H4CH2Cl), 5.15-5.09 (m, 10H, -CHOC2H4CHO-), 4.58-4.55 (m, 10H, -R2CHOCHR2-), 4.48-4.19 (m, 20H, - CH2OCOO-), 3.85-3.43 (m, 217H, -OCH2CH2- from 2.4kDa MPEG), 1.38-1.19 (m, 15H, -CH3). PDI: 1.13. Polymer 2g ^# :

Polymer 2g ^# was obtained by functionalization of 2g with azide. Polymer 2g was charged within a 20 mL glass vial with 3 mL DMF and sodium azide (3 eqv. to each pendant OBnCl), and left stirring at room temperature for 3 h. The reaction mixture was then passed through a 0.2 µm PTFE syringe filter to remove any undissolved salts, and then precipitated into cold diethyl ether twice. Two cycles of centrifugation/decantation of the supernatant, followed by drying under reduced pressure, afforded the desired polymer as a white solid (2g ^# ). ¹ H NMR (400 MHz, CDCl3, 22 ºC): δ 7.33-7.31 (m, 40H, -C6H4CH2N3), 5.15-5.08 (m, 20H, -CHOC2H4CHO- ), 4.40-4.38 (m, 20H, -R2CHOCHR2-), 4.32-4.13 (m, 40H, -CH ₂ OCOO-), 3.70-3.45 (m, 13H, -OCH2CH2- from MPEG 164), 1.28-1.19 (m, 30H, -CH3). PDI: 1.23. Polymer 2h ^# was synthesized in the same fashion as polymer 2g ^# , using a longer PEG initiator (MPEG2.4k-OH, MW =2.4 kDa) while keeping the degree of polymerization of MTC-CH2OBnCl constant.

1H NMR (400 MHz, CDCl3, 22 ºC): δ 7.43-7.29 (m, 20H, -C6H4CH2N3), 5.18-5.05 (m, 10H, -CHOC2H4CHO-), 4.45-4.37 (m, 10H, -R2CHOCHR2-), 4.36-4.18 (m, 10H, - CH ₂ OCOO-), 3.74-3.43 (m, 217H, -OCH2CH2- from 2.4kDa MPEG), 1.28-1.15 (m, 15H, -CH3). Example 6: Polymer coating and surface characterization PDMS silicone rubber was first exposed to ultraviolet/ozone (UVO) radiation to introduce hydroxyl groups onto its surface. 3-Mercaptopropyltrimethoxysilane was then deposited onto the surface to confer thiol functional groups through a condensation reaction. Subsequently and as shown in Figure 3, maleimide-containing polymers were grafted onto the PDMS surface to form a first layer/first layer polymer coating through Michael addition reaction of the maleimide pendant groups with thiol groups on the surface. Static contact angle measurements were carried out on both treated and untreated PDMS surfaces to evaluate wettability change. As demonstrated in Figure 4, after UV/ozone passivation of the PDMS silicone rubber surface, there was a significant and consistent decrease in surface contact angle, suggesting an increase in hydrophilicity with the introduction of hydroxyl groups (108.6 ± 0.7º vs. 22.3 ± 1.0º). Hydrophobicity was partially regained after subsequent surface functionalization with 3-mercaptopropyltrimethoxysilane, with a corresponding increase in static contact angle (84.1 ± 0.5º). First layers, especially those comprising a PEG block, such as polymers 1d and 1e, led to increased wettability with contact angles of ~60º-66º. The second layer/second layer polymer coating was formed by tethering the second layer polymer, such as cationic polymers 2a’ to 2f’ and 2a’’ to 2f’’, to the first layer through an azide-alkyne copper-click reaction, thereby forming a two-layer coating. Upon the successful tethering of this second layer, surface contact angles decreased by ~10º-20º, depending on architecture of the polymers and hydrophobicity of quaternizing agents. Comparing the contact angles for the two-layer coatings 1b+2e”, 1d+2e” and 1e+2e”, the wettability of two-layer coatings was increased with the presence of PEG and the increased length of the PEG chain. The successful grafting of the first layer of alkyne onto the thiol-functionalized PDMS surface was determined through high resolution XPS analysis of S2p. The appearance of a new peak at 164 eV correlated to the thiol ether bond, which was formed subsequently after free thiol groups (166 eV) on the thiol-functionalized surface reacted with the maleimide pendant groups of the first layer, while the original peak at 160 eV corresponded to the unreacted sulfhydryl groups (Figure 5). The covalent grafting of the second layer was observed under high resolution of XPS analysis of N1s. The appearance of the peak at 399 eV correlated to a C-N bond that was formed after successful click reaction between alkyne and azide moieties (Figure 4), and was also reported in previously published literature (W. J. Yang, D. Pranantyo, K.-G. Neoh, E.-T. Kang, S. L.-M. Teo, D. Rittschof, Biomacromolecules 2012, 13, 2769). In addition, two new peaks at 401 and 403 eV, corresponding to the nitrogen on the maleimide and quaternized nitrogen atom of the second layer, respectively, were also observed (Figure 4). Taken together, the results demonstrated successful covalent grafting of the individual polymer layers onto the thiol-functionalized surface. Example 7: Antibacterial activity of polymer-coated surfaces To evaluate antibacterial activity of polymer-coated surfaces/substrates, S. aureus and P. aeruginosa suspension was incubated with uncoated and polymer-coated PMDS rubber for one day. The number of live bacterial cells was analyzed by agar plating. The results in Figure 6 show that when a first layer made up of a maleimide-containing polymer such as polymer 1a was coated on the surface of a thiol-functionalized PMDS rubber, none of the first layer coatings 1a-1f demonstrated antimicrobial efficacy due to the lack of a cationic polymer, which is necessary for bacteria elimination (Figure 6). Consequently, the results show that a surface having only a first layer polymer coating comprising an alkyne- and maleimide-functionalized polycarbonate, an alkyne-functionalized diblock copolymer of PEG and maleimide/alkyne-functionalized polycarbonate or an alkyne-containing maleimide-functionalized diblock copolymer did not have any antibacterial activity. To evaluate the effect of anchoring group number on bacteria killing efficacy, three different polymers of varying DP (6, 15 and 34), namely polymers 1a, 1b and 1c, were used as the first layer and a second layer made up of a cationic polymer 2b’ (1-arm) was grafted on the first layer, thereby forming a two-layer coating (Figure 6a). When the polymers containing 6 or 15 maleimide groups (polymer 1a and 1b, respectively) were used as the first layer, 100% killing efficiency was achieved against S. aureus after one-day incubation. Increasing the number of maleimide groups to 34 (polymer 1c) led to a significant reduction in antimicrobial efficacy, possibly due to lower coating efficiency of polymer 2b’ stemming from reduced reactivity of alkyne group or steric hindrance in polymer 1c with a longer chain. Consequently, the results show that a surface having a first layer, such as a first layer comprising an alkyne- and maleimide- functionalized polycarbonate, combined with a second layer, such as a second layer comprising a cationic polymer, advantageously led to antibacterial activity. Notably, when the first layer comprises a polymer having 6 to 15 maleimide groups and less than 34 maleimide groups, 100% or nearly 100% killing efficiency was achieved against S. aureus after one-day incubation. The effect of 1-arm cationic polymer length on antimicrobial efficacy was further investigated by grafting three different cationic polymers of varying DP (22, 40 and 80) quaternized with N,N-dimethylbutylamine (polymers 2a’-2c’) onto the first layer made up of polymer 1b. The cationic polymer of DP 80 (polymer 2c’) as the second layer failed to kill surface bacteria (Figure 6b), even though it demonstrated antimicrobial property as a free polymer in solution (minimum inhibitory concentration-MIC: 3.9 µg/mL, Figure 7). In contrast, the cationic polymers of DP 22 (polymer 2a’) and 40 (polymer 2b’) proved to be more effective as the second layer against S. aureus, with polymer 2a’ and polymer 2b’ exhibiting more than 99.99999% (7-log reduction in colony counts) and ~100% killing efficiency, respectively. This stark difference in antimicrobial efficacy between polymer 2a’/ polymer 2b’ and polymer 2c’ was possibly due to ineffective coating of polymer 2c’, which might be caused by reduced reactivity of azide-alkyne bond formation arising from steric hindrance of azide moiety in polymer 2c’ due to its significantly longer chain. It is more difficult to eliminate Gram-negative bacteria such as P. aeruginosa because Gram-negative bacteria have an additional membrane on their surface. Polymers containing sufficient cationic charges and high hydrophobicity are needed to lyse the membrane of the Gram-negative bacteria. Second layer coatings with all 1-arm polymers (polymers 2a’, 2b’ and 2c’), regardless of DP, and 2-arm polymer 2d’, did not exhibit any significant antimicrobial efficacy against P. aeruginosa (Figure 6c). This was even when they were quaternized with the more hydrophobic quaternizing agent N,N-dimethyloctylamine (polymers 2a”and 2b”) and were demonstrated to exhibit antimicrobial activity as a free polymer (e.g. polymer 2b”, MIC=31.3 µg/mL, Figure 7b). Although polymers 2b” and 2f” had the same MIC in solution (Figure 7) and a comparable length of cationic block, only polymer 2f” coating exhibited antimicrobial efficacy against P. aeruginosa on surface (more than 6 log reduction in bacteria counts) (Figure 6c). Polymer 2d” was also less effective at killing bacteria on surfaces as compared to polymer 2f” (Figure 6c). This was possibly attributed to its 3-arm architecture, which may provide better surface coverage. The incomplete bacteria killing was also observed when PEG2.4k-containing polymer 1e as the first layer and polymer 2f” as the second layer (two-layer coating 1e+2f”, Figure 6c). However, when polymer 2e” having 2-arm architecture and a longer cationic polymer as compared to polymer 2f” was used as the second layer with either polymer 1b or 1e as the first layer, no live bacterial cells were found in the solution after one-day incubation with the polymer-coated surface (Figure 6c), thereby demonstrating potent antimicrobial efficacy. These findings indicate that cationic polymer length, hydrophobicity and architecture are important factors which affect antimicrobial activity on a surface/substrate. Example 8: Antifouling Activity of Polymer-coated Surface To quantitatively investigate the effect of the polymer coatings on surface bacterial fouling activity, colony forming units of surviving S. aureus and P. aeruginosa on surface were plated and colony forming units on agar plates were subsequently counted (Figure 8). A significant amount of S. aureus was demonstrable on the pristine (8.2 Log10CFU·disc ^-1 ) and thiol-functionalized (8.2 Log10CFU·disc ^-1 ) surfaces as well as the surfaces coated with polymer 1b or 1d as the first layer (8.3 and 7.7 Log10CFU·disc ^-1 , respectively) on Day 1 post incubation (Figure 8a). The cells began to adhere on the surfaces coated with polymer 1b as the first layer and cationic polymer 2b’ as the second layer just one day after incubation (3.3 Log10CFU·disc ^-1 ). Conversely, when polymer 1d having PEG was used as the first layer and cationic polymer 2b’ as the second layer, no fouling was observed on the surface even after 2-week incubation (Figure 8a). These results demonstrated that the presence of both PEG in the first layer and cationic polymer in the second layer was essential for the prevention of S. aureus fouling. In order to prevent P. aeruginosa fouling, a higher charge density and more hydrophobic second layer polymer coating (2e”, 2-arm; 2f”, 3-arm) was utilized. Similar to their activity in solution (Figure 7c), two-layer coatings 1b+2f” and 1e+2f” were unable to prevent P. aeruginosa fouling even after one-day incubation. The coatings with polymer 1d containing PEG164 or polymer 1e of PEG2.4k as the first layer polymer and cationic polymer 2e” with longer cationic polymer chain as the second layer polymer (1d+2e”, 1e+2e”) precluded P. aeruginosa fouling over 2 weeks (Figure 8b). Interestingly, the coating using polymer 1b without PEG as the first layer also exerted excellent antifouling activity against P. aeruginosa (Figure 8b) possibly because cationic polymer 2e” effectively killed the bacteria in solution (Figure 7c). As such, the bacteria had no chance to attach onto the surface. Prevention and removal of biofilm is notoriously difficult (G. Cazander, M. Veerdonk, C. J. E. Vandenbroucke-Grauls, M. J. Schreurs, G. Jukema, Clin Orthop Relat Res 2010, 468, 2789; P. Watnick, R. Kolter, Journal of Bacteriology 2000, 182, 2675. The ability of the polymer coatings to prevent biofilm formation was studied by confocal microscopic and FE-SEM analyses of both S. aureus (Figure 9) and P. aeruginosa (Figure 10). A significant amount of both bacterial species adhered onto both pristine and thiol-functionalized surfaces just one day after incubation. As expected, P. aeruginosa formed biofilm on these surfaces more easily than S. aureus, which required 1- and 7-day incubation, respectively. In the case of S. aureus, a similar phenomenon was also observed on polymer 1b- coated surface without PEG or a second layer cationic polymer (Figure 9). The incorporation of PEG into the first layer significantly reduced S. aureus fouling (polymer 1d vs. polymer 1b, Figure 9). Dead cellular debris was observed to adhere more significantly onto the second layer cationic surface with non-PEG incorporated first layer than the coating without the cationic polymer (two-layer coating 1b+2b’ vs. polymer 1b). The coating with PEG-containing 1d as the first layer and cationic polymer 2b’ as the second layer prevented biofilm formation over 14 days, and very few live cells were found on the surface. This finding is in agreement with antimicrobial and antifouling activities of the two-layer coating 1d+2b’ as shown in Figure 6a and Figure 8a, respectively. In the case of P. aeruginosa, biofilm was formed on pristine, thiol-functionalized and all first layer polymer-coated surfaces (1b, 1d and 1e) at Day 1 or Day 7 (Figure 11). The addition of the second layer 2-arm cationic polymer 2e” was essential to inhibit biofilm formation, and there were very few surviving bacteria on the surface even after 14-day incubation (two-layer coatings 1b+2e”, 1d+2e” and 1e+2e”, Figure 10). These findings again showed the presence of a cationic antimicrobial polymer as the second layer was important to eradicate P. aeruginosa and eliminate bacteria fouling. Example 8.1: Control An attempt to reverse the second cationic antimicrobial layer with the first PEG antifouling layer was made to investigate its effect on antimicrobial efficacy using the polymers synthesized in Example 5.4. Complete eradication of bacteria was achieved with the coating of the cationic polymer layer using polymer 1f’. When the cationic polymer layer was obliterated by the deposition of the second antifouling layer of varying PEG length using polymer 2g ^# or 2h ^# , so that two-layered coatings 1f’+2g ^# and 1f’+2h ^# were formed, antimicrobial efficacy was lost (Figure 12). This finding further proves that the coatings with PEG-containing polymers as the first layer and cationic polymers as the second layer are critical to eliminate bacteria fouling. Example 9: Prevention of protein and platelet adhesion without inducing hemolysis The adsorption of blood proteins may act as an underlying anchoring platform for the adhesion of bacteria and may thus undermine the antifouling/antibacterial functions of the polymer coatings. FITC-labeled bovine serum albumin (FITC-BSA) was used as a model protein to study protein adsorption on the uncoated and polymer-coated silicone rubber surfaces. The surfaces were analyzed by florescence. A significant amount of protein was found on the pristine silicone rubber surface and the surfaces coated with polymer 1b, two-layer coating 1b+2b’ and two-layer coating 1b+2e” without PEG. The presence of PEG in the first coating layer significantly decreased protein fouling (two- layer coating 1d+2b’ vs. two-layer coating 1b+2b’, two-layer coating 1d+2e” vs. two- layer coating 1b+2e”) (Figure 13). When polymer 1e with longer PEG (2.4 kDa) was used as the first layer, protein fouling was effectively prevented (two-layer coating 1e+2e” vs. two-layer coating 1d+2e”). This is in accordance with previous findings reported by K. D. Park et al (K. D. Park, Y. S. Kim, D. K. Han, Y. H. Kim, E. H. B. Lee, H. Suh, K. S. Choi, Biomaterials 1998, 19, 851). All the surfaces, coated or uncoated, had almost no or minimal hemolysis after treatment with rat red blood cells (Figure 14). Platelet fouling results were similar with the protein fouling data. Surfaces that were tethered with PEG-containing polymers such as polymers 1d and 1e resisted platelet fouling with polymer 1e having a longer PEG chain being more effective, and surfaces coated with two layers demonstrated greater reduction in platelet fouling when the first layer contained a longer PEG chain (2.4 kDa) (Figure 15). It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention. It is intended that all such modifications and adaptations come within the scope of the appended claims. Further, it is to be appreciated that features from various embodiment(s), may be combined to form one or more additional embodiments.