Field of the invention

The present invention relates to an ionic conducting polymeric material, a method for synthesizing the material and the uses thereof.

Technical background

5 Polymer electrolytes are polymeric materials that possess ionic groups, such as sulfonic acid groups, in the polymer chains. They may bond firmly to specific ions and may selectively pass cations or anions, and are used in widespread applications in the form of particles, fibers, solutions and membranes.

10 Existing polyelectrolytes are currently applied as fuel cell membranes, dialysis membranes and separation films for water purification such as reverse osmosis by desalination. For example, the contemporary demands from the industries for fuel cell use are to achieve a membrane with an inexpensive raw material cost, high ionic conductivity under various

15 conditions, efficient water flux, as well as hydrolytical, chemical, thermal and mechanical stabilities. Especially when it comes to the application of fuel cell vehicles led by automotive manufacturers, the operation conditions are from sub-zero temperatures in cold climates to hot and dry climates. The state-of- the-art membrane is the perfluorosulfonic acid (PFSA), such as Nafion ^®

20 developed by DuPont, which can meet a high proton conductivity thanks to the strong acidity and the well-defined phase separation between the hydrophilic and hydrophobic sequences. The performance and stability at temperatures above 100 ^° C need to be addressed in order to minimize the need for heating/cooling radiators in the vehicles, which occupy a large space

25 and result in a poor cost performance for commercialization. Unfortunately, the PFSA membrane materials show a poor fuel gas barrier and have a poor robustness of the fuel cell properties due to the low mechanical modulus at high temperatures. These issues become more critical when the membrane used are thinner and thinner to attain an efficient water management and a

30 low resistance in the fuel cell system.

Therefore, polyarylenes, such as poly(arylene ether sulfone)s, have received great attention because of their excellent thermal and chemical stabilities, their excellent gas barrier, as well as their relatively low raw material cost and simple molecular design. However, one of their large

35 drawbacks is a poor ionic conductivity at reduced relative humidity (RH). To compensate for this, numerous approaches have been investigated to improve the ionic conductivity under low RH, generally by way of inducing a strong phase separation between the hydrophilic and hydrophobic sequences for a further improvement of ion/water transport property from one to the other side of the membrane in fuel cells. The technical examples are a graft copolymerization from the polymer backbone, a di-, tri- and multiblock copolymer, a star, crosslinked or branched copolymer in order to achieve a good phase separation in membranes. Over the last years, one notable approach is to introduce a highly densed ionic domain in the resulting

(co)polymer, leading to a comparable ionic conductivity at reduced RH, as observed with PFSA membranes. However, the ionic groups in the

investigated materials are normally located on phenyl rings where electron- donor groups or bridges exist that easily bring about decomposition of the ions, especially desulfonation for sulfonic acid groups.

US2008/0207781A1 shows a material structure, the preparation method and the use that minimize the desulfonation issue and utilize densely sulfonated units to retain a high proton conductivity even at low RH:

sulfonated poly(arylenes) featuring the structural element -X-Ar(SO3M) _n -Y-, where the phenyl rings carrying the sulfonic acid groups are exclusively substituted by electron-acceptor bridge groups (electron withdrawing groups, e.g. sulfones -SO2- or ketones -CO-), X and Y, and, if applicable, by additional non-electron-donor substituents. However, their invention shows a limited polymerization ranging from homopolymer, statistical copolymer to multiblock copolymer, and the use of homopolymer for fuel cell is

questionable because it is water soluble at a high ion exchange capacity (IEC). Interestingly, they proved that the desulfonation was impeded by a careful positioning of sulfonic acid groups by way of a cyclic durability test. However, one large drawback will be to reach a precise control of morphology in the resulting polymer structure. For example, the preparation of statistical copolymers to attain an appropriate IEC value in order to avoid an excessive swelling behavior, by way of their invented method, may lead to the formation of randomly dispersed ionic sequences. In addition, there are few reports yet to prove a proper multiblock copolymer structure via oligomerization, most probably because the control of molecular weight and selective functional termination of oligomer is difficult by their invented method. One to be mentioned is by G. Titvinidze, K. D. Kreuer, M. Schuster, C. C. Araujo, J. P. Melchior, W. H. Meyer, Adv. Funct. Mater. 2012, DOI: 10.1002/adfm.20120081 1 . Therefore, there is a potential need to find materials and methods that can show new and further improved properties in relation to presently known products.

Summary of the invention

The obtained polymer according to the present invention has a synthetically controlled morphology. The morphology obtained enables the polymerized monomers having specific structural units to be polymerized into a polymer with a polydispersity index of about 2 in theory, insuring a lengthy ionic sequence with a precisely given length, if polycondensation is applied using the novel ionic macromonomers disclosed in the present invention.

Also, side chains of the structural unit according to the present invention may be provided. One objective of the invention is to remedy the drawbacks of the prior art. The present invention relates to a polymer material that has good electrochemical performances, in particular combining a high ionic conduction and a high mechanical strength. For example the present invention provides a material that has high proton conductivity at low RH. The material also has a relatively low water uptake. As expected from the chemical structure, the gas barrier and thermal/chemical/hydrolytical/dimensional stabilities are

appropriately high. The reproducibility and versatility of the method are high enough, because of the use of the novel ionic monomers disclosed in the invention, resulting in an excellent quality, cost performance and time efficiency of production for commercialization.

Another objective of the invention is to propose a method for synthesizing a polymer material that has a high ionic conductivity. It is a further objective of the invention to provide an industrial method of synthesis whereby the ionic conductivity of the polymer material can be controlled.

High ionic conductivity at low RH can in the present invention be achieved by not only highly ionic units in the resulting (co)polymers, but also efficient self-assembling properties thanks to a precisely given length of ionic sequences in between the polymer chains, in combination with homopolymer, statistical copolymer, di-, tri- multiblock copolymers for both main chain and side chain type polymer structures.

Water uptake and dimensional stability are related to each other. By devoiding any ether linkage, -O-, and any aliphatic moiety, the properties are excellent in the materials according to the present invention, especially when all thioethers are fully oxidized to sulfoxides or preferably sulfones. Since fully aromatic chemical structures are used as the backbone of the hydrophilic sequence of both main chain and side chain type polymer structures, the gas barrier and thermal stability are quite high. These

properties are expected, especially when the materials are designed without any flexible linkage, ether, -0-, and sulfur, -S-, which cause a depression of the glass transition point and an excessive hydration of such hydrophilic parts, leading to a poor dimensional stability.

All ions attached to the materials according to the present invention are located on the phenyl rings that are linked with sulfone bridges, where the decomposition of ionic groups is deactivated, resulting in a high

chemical/hydrolytical stability of the ions.

The invention provides the polymeric products and methodologies that bring about high performance, durable and reliable properties as cation exchange polyelectrolytes. The chemical structures include very rigid polyarylenes with high lECs in hydrophilic sequences, consisting of ionic phenyl rings continuously adjacent to other ionic phenyl rings or sulfone bridges, in either main-chain or side-chain type polymer structures.

As the invented materials are derived from some novel monomers that are prepared in advance of the polymerization, the control of the molecular weight and IEC is high.

The present invention relates to a polymeric material comprising structural elements of the following general formula (I):

- X ¹ - (Ph ¹ - X ² ) _m - (Ph ² - X ³ ) _n - (Ph ³ - X ⁴ ) ₍

(I) wherein

Ph ¹ , Ph ² and Ph ³ independently are phenylenes comprising acidic groups with or without a spacer or the salts thereof;

X ¹ , X ² , X ³ and X ⁴ independently are O, S, S0 ₂ , SO or a direct bond and wherein X ¹ also may be H termination when Formula (I) relates to side chains of the polymeric material, and wherein at least two of X ¹ , X ² , X ³ and X ⁴ are SO2 when the Formula (I) relates to main chains of the polymeric material or at least one of X ¹ , X ² , X ³ and X ⁴ is SO2 when Formula (I) relates to side chains of the polymeric material;

m, n and q independently are integers and m+n+q is at least 3 when Formula (I) relates to main chains of the polymeric material or

m+n+q is at least 2 if Formula (I) relates to side chains of the polymeric material,

wherein the sum m+n+q is identical for all structural elements in the polymeric material,

wherein, when the Formula (I) relates to main chains of the polymeric material and when any one of X ¹ , X ² , X ³ and X ⁴ is SO or SO2 then the Ph ¹ , Ph ² or Ph ³ , linked to SO or SO2, have at least one of the acidic groups, with or without a spacer or the salts thereof, positioned in ortho position in relation to SO or SO ₂ .

In another embodiment, when the Formula (I) relates to side chains of the polymeric material and any one of X ¹ , X ² , X ³ and X ⁴ is SO or SO2 then the Ph ¹ , Ph ² or Ph ³ , linked to SO or SO2, have at least one of the acidic groups, with or without a spacer or salts thereof, positioned in ortho position in relation to SO or SO ₂ .

According to another embodiment Ph ¹ , Ph ² or Ph ³ , linked to SO or SO2, has at least two or at least three of the acidic groups, with or without a spacer or salts thereof, positioned in ortho position in relation to SO or SO2.

The polymeric material according to the present invention may be produced by the following steps:

a) production of a sulfonated, phosphonated, carboxylated or borated phenyl sulfone monomer wherein the phenyl system is comprised of

either at least two phenyl rings which independently are substituted with at least two acidic groups when Formula (I) relates to side chains of the polymeric material

or at least three aromatic rings which independently are substituted with at least three acidic groups when Formula (I) relates to main chains of the polymeric material,

with or without a spacer between the phenyl rings and the acidic groups, wherein said acidic groups are selected from the group consisting of sulfonic acid, phosphonic acid, carboxylic acid, boronic acid group and any

combination of them,

and either at least two sulfone bridging groups when Formula (I) relates to main chains of the polymeric material or at least one sulfone bridging group when Formula (I) relates to side chains of the polymeric material, and wherein said phenyl system features functional groups F ¹ and F ² at respective ends, which may be identical or different from each other and can enter into a condensation reaction, a coupling reaction induced by a metal catalyst (e.g. Cu, Ni, Pd) or several various phenyl monomers of this kind;

b) polycondensation or nickel-catalyzed coupling reaction of the substituted arylene sulfone monomer of step a) during the formation of a sulfonated, phosphonated, carboxylated and/or borated polymer.

The metal catalyst used to induce the coupling reaction mentioned above may be e.g. Cu, Ni or Pd.

In some embodiments the monomer produced in step a) mentioned above is produced from the monomer derivative which may be obtained through an additional reaction, followed by metalation-oxidation.

In some embodiments the monomer produced in step a) mentioned above is produced from the monomer derivative which may be obtained through condensation followed by addition of fuming sulfuric acid. This condensation and sulfonation step may be repeated.

The polymeric material according to the present invention may be used for in a membrane material. In some embodiments the polymeric material according to the invention may be used in an ion exchange membrane.

The polymeric material according to the present invention may alternatively be used in an electrode assembly.

The polymeric material according to the present invention may alternatively be used in a fuel cell.

The polymeric material according to the present invention may alternatively be used as a polyelectrolyte for water purification, electrodialysis, Donnan dialysis, electrolysis, humidification/dehumidification, vanadium redox flow battery or electromagnetic screening.

Thus, the present invention also relates to all such applications as mentioned above, according to the present invention.

Short description of the drawings

Figure 1 shows the ¹ H NMR spectrum of monomer (1 ).

Figure 2 shows the ¹ H NMR spectrum of copolymer (2).

Figure 3 shows the ¹ H NMR spectrum of monomer (3).

Figure 4 shows the ¹ H NMR spectrum of monomer (4).

Figure 5 shows the ¹ H NMR spectrum of copolymer (5).

Figure 6 shows the water uptake of copolymers under IEC of 2 meq./g.

Figure 7 shows the proton conductivities at 80°C as a function of RH of copolymers under IEC of 2 meq./g. Figure 8 shows the ¹ H NMR spectrum of monomer (6).

Figure 9 shows the ¹ H NMR spectrum of copolymer (7).

Figure 10 shows the ¹ H NMR spectrum of oligomer (8).

Figure 1 1 shows the ¹ H NMR spectra of oligomer (9) before and after end capping by hexafluorobenzene.

Figure 12 shows the ¹ H NMR spectra of multiblock copolymers (10) and (11).

Figure 13 shows the hydration number of copolymers in water as a function of temperature.

Figure 14 shows the humidity dependence of proton conductivity of multiblock copolymers at 80°C.

Detailed description of the invention

The present invention relates to polyelectrolytes comprising structures with aromatic groups connected with sulfone bridges, wherein at least some of the aromatic groups comprise at least one ionic group. The aromatic groups are preferably arylene sulfones comprising substituent(s) on the phenylene group, at least one ionic group. The present invention relates to polyelectrolytes which e.g. may be used for fuel cells, reverse osmosis, diapers and surfactants.

The polyelectrolytes of the present invention may have a backbone of hydrophilic and/or hydrophobic sequences. The backbone is preferably made of aromatic compounds.

Bridging groups between aromatic or aliphatic components are chosen from sulfone (-SO2-), sulfoxide (-SO-), ether (-O-), sulfide (-S-) or direct bond (Ph-Ph).

According to one embodiment the present invention relates to the backbone consisting of aromates and bridges such as ether bridges (-O-), thioethers (-S-), sulfoxide (-SO-) or sulfone bridges (-SO2-).

The present invention discloses new polymeric materials comprising substituted poly(phenylenes) featuring the structural element Formula (I):

- X ¹ - (Ph ¹ - X ² ) _m - (Ph ² - X ³ ) _n - (Ph ³ - X ⁴ ) _q

(I) wherein the phenylene rings comprise at least one acidic group or its salt attached directly onto the rings or via a spacer such as aliphatic or aromatic chains, wherein said phenylene rings are bridged by either sulfoxides or sulfones, as well as their synthesis and use.

The polymers according to the invention are referred to as poly(arylene sulfone)s containing one or several structural elements of the Formula (I), wherein X ¹ , X ² , X ³ and X ⁴ independently are identical or different from each other, and chosen from O, S, SO2, SO and a direct bond. X ¹ may also be a H termination when Formula (I) relates to side chains of the polymeric material.

Furthermore at least two of X ¹ , X ² , X ³ and X ⁴ are SO or SO2 when the Formula (I) relates to main chains of the polymeric material or at least one of X ¹ , X ² , X ³ and X ⁴ is SO or SO ₂ when the Formula (I) relates to side chains of the polymeric material. Ph represents phenylene.

The bridge groups X ¹ , X ² , X ³ and X ⁴ are present at phenylene rings in the meta or para position, preferably para position. Suitable examples of X ¹ , X ² , X ³ and X ⁴ are O, S, SO, SO ₂ or direct bond, preferably SO ₂ or direct bond and especially preferred SO2.

Surrounding the SO or SO2 are the phenylene rings, which adjacent pheneylene rings together have at least at least two or at least three of the acidic groups, with or without a spacer or salts thereof, positioned in ortho position in relation to the linking SO or SO2. All acidic groups present on phenylene rings linked with SO or SO2 may be positioned in ortho positions of the adjacent phenylene rings in relation to the linking SO or SO2.

According to one embodiment a polymeric material is provided, which comprises structural elements of the following general formula (I):

- X ¹ - (Ph ¹ - X ² ) _m - (Ph ² - X ³ ) _n - (Ph ³ - X ⁴ ) _q (I) wherein

Ph ¹ , Ph ² and Ph ³ independently are phenylenes comprising acidic groups with or without a spacer or salts thereof;

X ¹ , X ² , X ³ and X ⁴ independently are O, S, SO, SO ₂ , or a direct bond and wherein X ¹ also may be H termination when Formula (I) relates to the side chains of the polymeric material, and wherein at least two of X ¹ , X ² , X ³ and X ⁴ are SO2 when Formula (I) relates to main chains of the polymeric material or at least one of X ¹ , X ² , X ³ and X ⁴ is SO2 when Formula (I) relates to side chains of the polymeric material;

m, n and q independently are integers and m+n+q is at least 3 when Formula (I) relates to main chains of the polymeric material or

m+n+q is at least 2 when Formula (I) relates to side chains of the polymeric material,

wherein the sum m+n+q is identical for all structural elements in the polymeric material. Optionally, when any one of X ¹ , X ² , X ³ and X ⁴ is SO ₂ then the Ph ¹ , Ph ² or Ph ³ , linked to SO ₂ , have at least one of the acidic groups, with or without a spacer or salts thereof, positioned in ortho position in relation to SO ₂ .

If the structural elements relate to a monomer the structure may be presented according to Formula (II)

1 1 2 2 3 3 4 2

F - (Ph - X ) - (Ph - X ) - (Ph - X ) - F

m n q _{( M )} which compared to Formula (I) comprise the further elements F ¹ and F ² .

F ¹ and F ² which may be identical or different from each other and are preferably selected from halogen atoms such as fluorine, chlorine, bromine or iodine, or possibly nucleophiles such as ol (-OM) or thiol (-SM), where M represents H, silyl derivative (e.g. -Si(CH ₃ ) ₃ ) or any monovalent metal such as K, Na, Li. F ¹ and F ² , respectively, may further include in addition to the atoms, nucleophiles, derivatives or metals also include a phenylene ring comprising at least one acidic group or the salt thereof attached directly onto the ring or via a spacer such as aliphatic or aromatic chain.

The phenylene ring can be substituted with one to four acidic groups, the derivatives or salts thereof, preferably one or two acidic groups, and more preferably one acidic group. If the substituent is a salt it contains a

conventional cation, if monovalent cation, e.g. selected from Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ or ammonium ion derivatives, if divalent cation, e.g. Ca ²⁺ , Mg ²⁺ , Ba ²⁺ in combination with a complex with more than one acidic group in the polymer The phenylene rings comprise at least one acidic group or its salt attached directly onto the rings or via a spacer. On phenylene rings

connected to a bridging SO ₂ group, the at least one acidic group or its salt is attached to the phenylene ring in an ortho position in relation to the SO or SO ₂ group. The acidic groups or their salts attached to phenylene rings in contact with a SO or SO ₂ group are firstly attached in the ortho position(s) on the phenylene ring to the SO or SO ₂ group. That is, Ph ¹ , Ph ² and Ph ³ , independently, preferably have any acidic groups or the salts thereof attached to phenylene rings in contact with a SO or SO2 group in an ortho position in relation to said SO or SO2 group.

However, there is one exception to this and that is if the phenylene ring is at the ends of a chain, i.e. is included in the F ¹ or F ² group as disclosed above, then the at least one acidic group or the salt thereof may be found in a meta position on the ring in relation to a linked SO or SO2 group.

If the acidic groups or the salts thereof were attached to the

phenylenes in a ortho position to any other linkages than SO or SO2 bridges (e.g., Ph-Ph covalent bond, ether, thioether, amin, alkyl spacer), this will lead to cyclization with an adjacent phenylene having an acidic group or salt thereof in a similar meta position. The acidic groups would be located closely and thus easily reacted and forming a cyclic bonding via the meta and para positions.

However, if F ¹ and/or F ² include a substituted phenylene as disclosed above, any at least one acidic group or salts attached to the phenylene rings in contact with a SO or SO2 group is in an ortho or meta position in relation to said SO or SO2 group. Also any acidic groups or the salts thereof attached to a phenylene ring within F ¹ or F ² in contact with another bridging group like O, S, SO or a direct bond may be in a meta position in relation to said bridging group.

The acidic group or the salt may or may not be directly attached to the phenylene ring. A spacer, for instance available via metalation, such as aliphatic or aromatic chains may be linkages between the phenylene ring and the acidic group, the derivative or the salt. Occuring only under quite severe conditions such as a high pressure and a high temperature than 200 °C, the ionic groups in ortho positions to the sulfone bridges may induce a cleavage of the covalent bond between phenylene and sulfone bridges. Therefore, if a carbon-carbon covalent bond is situated between the phenylene ring and the acid, the derivative or the salt, such undesirable cleavages will not really take place. For example, a lithiated arylene sulfone structure unit may react with a nucleophile containing aromatic or aliphatic moieties, such as 2-bromoethyl sulfonate, butanesultone.

The phenylene rings may also contain additional non-electron-donor substituents. Some specific examples, without limitation, for such substituents are halogen, e.g. F, CI, Br, or unsubstituted or substituted alkyl groups, e.g. -CH ₃ or -CF ₃ . Especially preferred substituents are sulfonated, phosphonated, carboxylated or borated poly(arylene sulfone)s. As mentioned above, a spacer may be incorporated between the phenylene rings and the ionic groups.

Another subject of the present invention is copolymers that, in addition to recurring elements of substituted poly(arylene sulfone)s, as described above, also contain (preferably recurring) elements of at least one additional monomer or macromonomer.

Basically, any compound that can be copolymerized with the novel ionic monomers used according to the invention is suitable as additional co- monomer. Typically, it will be any diol, dithiol or dihalide compound in any orientation for chain extention, however preferably the meta- or the para-, more preferably the para-orientation especially for the hydrophilic units. In general, the diol compound will feature the formula HO-W-OH, the dithiol the formula HS-W-SH and the dihalide compound the formula Hal-W-Hal, wherein W is selected from the group consisting of -(CH ₂ ) _n -, -(CF ₂ ) _n -,

-(CF ₂ CH ₂ )n-, -(CH ₂ -CH ₂ -0) _n -CH ₂ -CH ₂ -, -(CH(CH ₃ )-CH ₂ -0)n-CH(CH ₃ )-CH ₂ -, -(CF ₂ -CF ₂ -0) _n -CF ₂ -CF ₂ -, in addition to any typical structure, -Ph- -Ph-S0 ₂ - Ph-, -Ph-S-Ph-, -Ph-O-Ph-, -Ph-SO-Ph, -Ph-Ph- for poly(arylene ether sulfone)s, -Ph-CO-Ph- for poly(arylene ether ketone)s, -(SiR ₂ -0) _n - for polysiloxanes. Hal in the dihalide compound represents a halogen residue, e.g. F, CI, Br and I. On top of these co-monomers, any macromonomer without ionic modification, for example disclosed in the invention, may also be used alternatively.

The pure, substituted poly(arylene sulfone)s or the copolymers, according to the invention, can also be mixed with one or more conventional polymers in a known manner in order to obtain a polymer mixture that combines the advantageous characteristics of its individual components. For example, the polymers according to the inventions may be mixed on the basis of a substituted poly(arylene sulfone) with "softening components" in order to provide the resulting mixed polymer with greater flexibility or formability.

Suitable polymers are known to the expert and can be selected, for example, from the group of polybenzimidazole (PBI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polysulfones (PSU), polyether sulfones (PES), polyether ketones (PEK), polyphenylene oxides (PPO), polyphenylene sulfides (PPS), polyimides (PI), polycarbonates (PC), polymethyl

methacrylates (PMMA), polyphosphazenes. In a specific embodiment, the pure, substituted poly(arylene sulfone)s, the copolymers or the polymer compounds of the invention can be integrated into an inert porous matrix, such as an organic (porous polyethylene (PE), polypropylene (PP), PVDF, PTFE, etc.) or inorganic matrix (porous

boronitride, silicon dioxide, etc.).

In another embodiment, the pure, substituted poly(arylene sulfones), the copolymers or the polymer compounds of the invention can be reinforced with fiber materials, such as glass fibers, ceramic fibers, textile fibers, carbon fibers, microporous PP or PTFE, etc.

Furthermore, the pure, substituted poly(arylene sulfone)s, the copolymers or the above polymer compounds of the invention can be combined with active or inactive fillers, including, but not limited to, ΤΊΟ2, Zr0 ₂ or S1O2 particles, zirconium phosphates and phosphonates, tungstic or molybdic acid, etc. in addition to cerium or cesium phosphate oxide or such derivatives, to form the corresponding composite materials. A combination with other conventional additives is also easily possible.

The substituted poly(arylene sulfone)s of the invention have molecular weights in the range of 2,000 to 2,000,000, typically in the range of 2,000 to 1 ,000,000, more frequently in the range of 10,000 to 1 ,000,000, preferably in the range of 2,000 to 200,000, especially preferably in the range of 10,000 to 100,000.

More frequently, however, the production of the substituted polymer involves a polycondensation of already substituted monomers, in this case sulfonated, phosphonated, carboxylated and/or borated monomers. In this way, the composition and properties of the resulting substituted

polyphenylene can be adjusted as desired.

In general, such a production method involves the following steps:

a) Production of a sulfonated, phosphonated, carboxylated or borated phenyl sulfone monomer wherein the phenyl system is comprised of:

either at least two aromatic rings which independently are substituted with at least two acidic groups for the side chain type polymer material,

or at least three aromatic rings which independently are substituted with at least three acidic groups for the main chain type polymer material,

with or without a spacer between the phenyl rings and the acidic groups, wherein said acidic groups are selected from the group consisting of sulfonic acid, phosphonic acid, carboxylic acid, boronic acid group, and any

combination of them; and either at least two sulfone bridging groups for the main chain type polymer material or at least one sulfone bridging group for the side chain type polymer material; and wherein said phenyl system features functional groups F ¹ and F ² at respective ends, which may be identical or different from each other and can enter into a condensation reaction, a coupling reaction induced by a metal catalyst or several various phenyl monomers of this kind;

b) Polycondensation or coupling polymerization of the substituted arylene sulfone monomer of step a) during the formation of a sulfonated,

phosphonated, carboxylated and/or borated polymer.

In one variant of this method, the polycondensation, in addition to one or more sulfonated, phosphonated, carboxylated and/or borated phenyl monomers, as defined above, also involves one or more phenyl monomers, representing a phenyl system comprised of one or more aromatic rings not substituted with a sulfonic acid, phosphonic acid, carboxylic acid or boronic acid group, and the said phenyl system featuring functional groups Fi and F ₂ , as defined above, which may be identical or different from each other.

The functional groups Fi and F ₂ of the phenyl monomers, identical or different, are preferably selected from the group consisting of fluorine, chlorine, bromine or iodine, optionally further comprising a phenylene group including at least one acidic group with or without a spacer or the salt thereof in a meta or ortho position as disclosed above.

Preferred solvents for the polymerization reaction or copolymerization reaction are aprotic, polar, high-boiling solvents, such as 1 -methyl-2- pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethyl acetamide (DMAc), sulfolane, diphenyl sulfone, 1 ,3-dimethyl-2- imidazolidinone, while any azeotropic solvent for condensation may be co- used, such as toluene, cyclohexane, chlorobenzene, benzene etc.

The reaction temperature is typically 40-300°C, preferably 80-200°C, more preferably 100-180°C.

The above mentioned monomer units may be used to form homopolymers, statistical and gradient copolymers or di-, tri-, multiblock copolymers in both main chain and side chain type polymer structures.

The new material according to the present invention possesses better periodical patterns of ionic units. This regularity obtained in the polymeric chains due to larger and specifically given units are expectedly resulting in more narrow or more designable peaks in NMR analyses. From the theoretical point of view of the polymer mechanism using the novel ionic monomers if polycondensation is used, the polydispersity index (PDI) of polymers developed according to the present invention show close to the ideal value, 2 which can hardly be achieved by the materials disclosed in US2008/0207781A1 and any general block/graft copolymers. The PDI will generally be evaluable by either gel permeation chromatography (GPC) in an appropriate developing solvent or time of flight mass spectrometry (TOFMS). Moreover, small-angle x-ray scattering (SAXS) or small-angle neutron scattering (SANS) will be able to detect periodic patterning of ionic domains. Microscopic measurement, such as atomic force microscope (AFM), scanning electron microscope (SEM) or transmission electron miscroscpoe (TEM), may be able to image a morphological effect on the surface or in the bulk of membranes.

The substituted poly(arylene sulfone)s according to the present invention can be characterized by various methods, e.g. by means of NMR, water absorption tests and conductivity measurements. Some results of tests made are shown in FIGS. 1 -14.

In one embodiment according to the present invention the production of sulfonated arylene sulfone monomers involves the following steps:

a) Metalation of arylene sulfone halide monomers. The metalation process results in metal ions being exclusively attached towards the ortho- positions to the sulfone bridges or fluorine atoms in the case of monomers used in the invention. The metalation may be performed by using an organometal reagent e.g. n-butyllithium. Metalation by use of a lithium containing compound is called lithiation.

b) After the metalation, the metals onto arylene sulfones are replaced with any subsequent nucleophile. The lithiated arylene sulfones are reacted with sulfur dioxide, leading to the formation of the sulfinated products.

c) The sulfinates may be further oxidized by e.g., hydrogen peroxide to the sulfonates.

d) The cations, lithium ion if lithiation was the used metalation, may or may not be substituted with another cation. In the currently disclosed monomers, Li ⁺ was converted to Na ⁺ , since the monomers were purified by salt-out with NaCI.

In another embodiment according to the present invention the production of a phosphonated, a carboxylated, or a borated arylene sulfone monomer involves similar steps as mentioned above. From the ionic monomers according to the present invention polymers may be prepared by polycondensation of the monomers in the presence of K2CO3, dimethyl sulfoxide and cyclohexane, in addition to any type of co- monomer. When halogens of the monomer are chlorines, bromines or iodines, nickel-catalyzed coupling reaction may be used to prepare the (co)polymer based on the ionic monomers, for example, by use of chlorine-halide

monomers in the presence of (Ph ₃ P) ₂ NiCl2, Ph ₃ P, Zn, Nal, /V-methyl pyrrolidone. Optionally if there are thioethers in between, these may be oxidized by hydrogen peroxide to sulfoxides or sulfones.

The above-mentioned substituted arylene sulfone monomers according to the present invention may be polymerized. It is essential to use the monomers containing at least three phenyl rings and at least two sulfone bridges to polymerize the backbone of ionic sequences for a main chain type polymer structure.

This type of chemical structure may also be used for side chains type polymer structure. Then it is possible to use the monomers containing at least two phenyl rings and at least one sulfone bridge.

One issue for the present invention is to obtain a novel sulfonated monomer that may be used to produce a novel polymeric material and its production method. For the last couple of last years, two approaches have been investigated to achieve a tetrasulfonated monomer, as illustrated in the scheme below. The synthetic technique according to the present invention, lithiation chemistry, as can be seen in the left side of the scheme, has been proving to obtain the desired chemical structure. On the other hand, the other disclosed synthetic route on the right side of the scheme below, which many researchers apply for their research does not give the corresponding

tetrasulfonated product. It has been found that such a procedure as disclosed on the right side of the scheme induces a cyclization of sulfonic acids leading to the sulfone bridges on the biphenyl unit (a disulfonated monomer, termed as sBCPSBPms), whereas several publications have claimed that the tetrasulfonated monomer was successfully prepared without assumption of the cyclization possibility. There are references to report on the cyclization (V. K. Olkhovik, D. A. Vasilevskii, A. A. Pap, G. V. Kalechyts, Y. V. Matveienko, A. G. Baran, N. A. Halinouski, V. G. Petushok, ARKIVOC 2008, (ix) 69; E. Neofotistou, C. D. Malliakas, P. N. Trikalitis, Chem. Eur. J. 2009, 15, 4523; and J. P. Bassin, R. J. Cremlyn, J. M. Lynch, F. J. Swinbourne, Phosphorus, Sulfur Silicon 1993, 78, 55). The present invention is able to show a good polymerizability of the novel monomer, denoted as sBCPSBPos in the scheme, and an improved performance in comparison with any conventional materials.

sBCPSBPos

The scheme above is disclosing synthetic pathways to the

tetrasulfonated BCPSBP monomer with the sulfonic acid groups located in ortho-positions to the sulfone bridges (sBCPSBPos), and to the disulfoned BCPSBP with the acid groups in meta-position (sBCPSBPms) to the sulfone bridges. Parameters: (i) n-BuLi/THF, -70 °C; (ii) S02/THF, -70 °C; (iii) H202/H20, 40 °C; (iv) NaCI, (v) fuming sulfuric acid, 1 10 °C; (vi) NaCI.

Examples

The invention is further illustrated in the examples below. These examples shall in no way be considered to limit the scope of the patent.

Reference 1

4,4'-Dichlorodiphenyl sulfone (DCDPS) (5.0 g, 17.4 mmol) was first dissolved in tetrahydrofuran (THF) (100 mL) at room temperature in a reactor fitted with a gas inlet/outlet, a SO2 gas tube/inlet, a thermometer and a septum. The solution was cooled to -70 ^° C using a dry-ice/ isopropyl alcohol (IPA) bath. Subsequently, it was degassed using at least 7 argon-vacuum cycles, before slowly adding the n-BuLi solution (15.0 mL, 37.5 mmol). After 1 h, SO2 gas was quickly introduced and the color instantly became bright yellow. The solution was kept at -70 ^° C for 30 min and thereafter the

temperature was allowed to increase to close to 0 ^° C. A yellow powder was obtained by filtration and dried on the glass filter. In order to avoid any decomposition of sulfinated moiety, the powder was rapidly placed in a mixture of H2O2 (1 1 ml_) and H ₂ 0 (77 ml_) and heated at a temperature of 40 ^° C overnight. After boiling for 30 min at a temperature of 1 10 ^° C to quench any radicals from H2O2, followed by filtration to extract the insoluble product in water, the product was precipitated out in hot water by addition of NaCI until the mixture became cloudy. The crude monomer was then purified by repeating a re-crystallization from water/IPA (about 20 vol. /vol. %) three times.

The obtained yield of the monomer was 3.2 g. The obtained monomer, monomer (1 ), was identified by ¹ H NMR spectroscopy (see Fig. 1 ).

Reference 2

DCDPS (0.3018 g, 1 .051 1 mmol), monomer (1 ) (0.4851 g, 0.9875 mmol), biphenol (0.3741 g, 2.0090 mmol), K ₂ C0 ₃ (0.3332 g, 2.4108 mmol), dimethylacetamide (DMAc) (5.0 ml_) and toluene (5.0 ml_) were put in a two- neck flask (50 ml_) equipped with a magnetic stirrer, a N ₂ inlet, a Dean-Stark trap filled with toluene and a condenser fit with a CaC trap. The solution was heated at 160 ^° C for 4 h for dehydration by removing the toluene. The temperature was then increased to 175 ^° C for 3 days to complete the polycondensation, before the polymer product was precipitated in IPA, followed by a wash in deionized water. The obtained polymer was filtered and dried at 60 ^° C in a vacuum oven for 24 h.

The finally obtained polymer, copolymer (2), showed a yield of 90% and an IEC of 1 .88 meq/g. Copolymer (2) was identified by ¹ H NMR spectrum (Fig. 2).

Example 1

4,4 ^! -Bis[(4-chlorophenyl)sulfonyl]-1 , 1 '-biphenyl (BCPSBP) (5.0 g, 9.9 mmol) was first added into THF (200 ml_) at room temperature in a reactor fitted with a gas inlet/outlet, a SO2 gas tube/inlet, a thermometer and a septum. As BCPSBP was not soluble at room temperature, a certain heat to about 40 ^° C was applied to the reactor, leading to a colorless transparent solution. Then, the solution was cooled to -70 ^° C using a dry-ice/IPA bath. Subsequently, it was degassed using at least 7 argon-vacuum cycles, before slowly adding a n-BuLi solution (17.1 ml_, 42.8 mmol). After 1 h, SO2 gas was quickly introduced and the color instantly became bright yellow. The solution was kept at -70 ^° C for 30 min and thereafter the temperature was allowed to increase to close to 0 ^° C. A yellow powder was obtained by filtration and dried on the glass filter. In order to avoid any decomposition of sulfinated moiety, the powder was rapidly placed in H2O2 (13 ml_) and H ₂ 0 (87 ml_) and heated at 40 ^° C overnight. After boiling for 60 min at a temperature of at 1 10 ^° C to quench any radicals from H2O2, followed by a filtration to extract the insoluble product in water, the product was precipitated out into hot water by addition of NaCI until the mixture became cloudy. The crude monomer was then purified by repeating a re-crystallization from water/IPA (ca. 20 vol. /vol. %) three times.

Na0 ₃ S Na0 ₃ S

The obtained yield of the monomer was 4.26 g. The obtained

monomer, monomer (3) was identified by ¹ H NMR spectrum (see in Fig. 3). Example 2

H2SO4/SO3 (30%, 54 ml_, 320 mmol) was introduced to BCPSBP (20 g, 40 mmol) in a 100-mL two-necked flask, equipped with a magnetic stirrer and a condenser fitted with two aq. KOH trap flasks. The reactor was heated up to 1 10 °C and the components were allowed to react for 6 h. After the reaction, the solution was cooled down to room temperature, and N ₂ was purged to remove an excess of SO3 gas overnight. The product was then put in ice/water, and NaCI was added at elevated temperature until it was salted out. The collected product by filtration was redissolved in hot deionized water for neutralization by NaOH, followed by addition of NaCI for the salt-out. After the filtration, the obtained monomer was recrystallized by deionized water twice and water/IPA mixture seven times.

The overall yield of the monomer was 40%. The obtained monomer, monomer (4) was identified by ¹ H NMR spectrum and EI-MS (see in Fig. 4). Example 3

DCDPS (0.3720 g, 1 .2955 mmol), monomer (3) (0.4493 g, 0.4879 mmol), biphenol (0.3321 g, 1 .7835 mmol), K ₂ C0 ₃ (1 .2324 g, 8.9174 mmol), dimethyl sulfoxide (DMSO) (5.0 ml_) and cyclohexane (5.0 ml_) were put in a two-neck flask (50 ml_) equipped with a magnetic stirrer, a N ₂ inlet, a Dean- Stark trap filled with cyclohexane and a condenser fit with a CaC trap. The solution was heated for 4 h at temperature of 1 10 ^° C for dehydration under a reflux of the cyclohexane. Thereafter, the cyclohexane was removed, and the reaction solution was kept at 1 10 ^° C for 48 hours to complete the

polycondensation, before the product was precipitated in IPA, followed by a wash in deionized water. The obtained copolymer, copolymer (5), was filtered and dried at 60 ^° C in a vacuum oven for 24 h (yield: 99%, IEC: 2.02 meq/g), and identified by ¹ H NMR spectrum (see in Fig. 5)

K ₂ C0 ₃ , DMSO/cyclo exane

H ⁺ , H ₂ 0

Example 4

The water uptake, or the hydration number per sulfonic acid group, in the membranes of copolymer (2) and copolymer (5) was measured by the weight difference before and after soaking in water with a control of temperature, as shown in Fig. 6. As a result, inspite of the similar IEC value, copolymer (5) showed a larger water uptake most probably due to the larger ionic domain.

Example 5

The humidity dependence of proton conductivity of the membranes of copolymer (2) and copolymer (5) was investigated with a range 30 - 90%RH at 80 ^° C in a four-probe method. As seen in Fig. 7, the copolymer (5) showed much higher proton conductivity in the full range of RH, compared with copolymer (2). Example 6

BCPSBP (14.67 g, 29.14 mmol), 4-fluorothiophenol (7.0 ml_, 54.61 mmol), K2CO3 (4.9 g, 35.5 mmol) and DMAc (87 ml_) were put in a two-neck flask (250 ml_) equipped with a magnetic stirrer, a N ₂ inlet and a condenser fit with a CaC trap. The solution was kept at 40 ^° C for 24 h for the condensation reaction. The product was precipitated in IPA, followed by in a wash in deionized water several times, after the filtration to remove the salts. The product was recrystalized with toluene and dried at 30 ^° C in a vacuum oven for 24 h (yield: 82%).

The obtained product (12.0 g, 17.5 mmol) was first added into THF

(420 ml_) at room temperature in a reactor fitted with a gas inlet/outlet, a SO2 gas tube/inlet, a thermometer and a septum. As it was not soluble at room temperature, heating to about 40 ^° C was applied to the reactor, leading to a colorless transparent solution. Thereafter, the solution was cooled to -70 ^° C using a dry-ice/IPA bath. Subsequently, degassing was performed using at least 7 argon-vacuum cycles, before slowly adding a n-BuLi solution (57.3 ml_, 143 mmol). After 1 h, SO2 gas was rapidly introduced and the color instantly became bright yellow. The solution was kept at -70 ^° C for 30 min and thereafter the temperature was let close to 0 ^° C. The yellow powder was obtained by filtration and well dried on the glass filter. In order to avoid any decomposition of sulfinated moiety, the powder was rapidly placed in H2O2 (36 ml_, 35%) and H ₂ 0 (254 ml_) and heated at 40 ^° C overnight. After boiling for 60 min at 1 10 ^° C to quench any radicals from H2O2 and followed by the filtration to extract the insoluble product in water, the water was evaporated under vacuum by heat to obtain the product solid. Then, it was put in acetic acid (210 ml_) with sulfuric acid (22 ml_) and hydrogen peroxide (18 ml_, 35%) for further oxidation at 30 ^° C for 2 days and at 1 10 ^° C for 60 min. Then, the acetic acid and the water were removed by rotary evaporator, and the powder was redissolved in deionized water to neutralize the solution by adding sodium hydroxide and sodium bicarbonate. After removal of water, the product was redissolved in DMSO and filtered to remove the salts. The filtrate was then precipitated in IPA and washed in a fresh IPA. The monomer, monomer (6), was finally collected by dialysis treatment at room temperature in deionized water for 1 day, evaporating the water and vacuum drying, as characterized in Fig. 8 (Yield: 40%).

Example 7

DCDPS (0.3564 g, 1 .2410 mmol), monomer (6) (0.4543 g, 0.3333 mmol), biphenol (0.2931 g, 1 .5743 mmol), K ₂ C0 ₃ (1.09 g, 7.89 mmol), DMSO (4.0 ml_) and cyclohexane (4.0 ml_) were put in a two-neck flask (50 ml_) equipped with a magnetic stirrer, a N ₂ inlet, a Dean-Stark trap filled with cyclohexane and a condenser fit with a CaC trap. The solution was heated for 4 h at 1 10 ^° C for dehydration under a reflux of the cyclohexane. Thereafter, the cyclohexane was removed, and the reaction solution was kept at 1 10 ^° C for 1 week to complete the polycondensation, before the product was precipitated in IPA, followed by a wash in deionized water. The copolymer obtained, copolymer (7), was filtered and dried at 60 ^° C in a vacuum oven for 24 h (Yield: 85%), as identified in Fig. 9.

K ₂ C0 ₃ , DMSO/cyclohexane

H ⁺ , H,0

Example 8

Monomer (6) (1 .8586 g, 2.0389 mmol), 1 ,4-benzenedithiol (0.3189 g, 2.2418 mmol), K ₂ C0 ₃ (3.10 g, 22.4 mmol) and DMSO (8.0 ml_) were put in a two-neck flask (50 ml_) equipped with a magnetic stirrer, a N ₂ inlet and a condenser fit with a CaC trap. The solution was heated at 1 10 ^° C and kept for 3 days to complete the polycondensation, before the product was precipitated in IPA after the filtration to get rid of the salts, followed by a dialysis in deionized water for 2 days. The oligomer (8) was obtained by evaporating the dialyzed water and drying at 60 ^° C in a vacuum oven for 24 h (Yield: 60%, M _n : 1 1.6 kDa determined by ¹ H NMR), as identified in Fig. 10.

Example 9

DCDPS (9.2730 g, 32.2908 mmol), bisphenol S (8.4666 g, 33.8285 mmol) and K2CO3 (5.63 g, 40.8 mmol) were introduced in the reactor together with DMAc (75 ml_) and toluene (40 ml_). The dehydration step was carried out at 160 ^° C for 4 h, and the subsequent polymerization took place at 175 ^° C during 24 h. The obtained product was then precipitated in excess IPA which was then replaced with fresh IPA and hot deionized water. After filtration and vacuum drying at 80 ^° C, the oligomers were redissolved in DMAc, precipitated in IPA, and leached with fresh IPA and hot deionized water, followed by vacuum drying at 80 ^° C (overall yield: 90%, M _n = 6.4 kDa).

The obtained oligomer (10.00 g, 1 .57 mmol of the polymer chain) was added to a mixture of hexafluorobenzene (3.6 mL, 31 mmol) and K2CO3 (2.17 g, 15.7 mmol) in n-methyl-2-pyrrolidone (NMP) (40 mL), and then heated to 80 ^° C for 1 day, followed by precipitation in IPA as well as in hot deionized water (overall yield: 90%, M _n = 6.7 kDa). The completion of the end capping reaction was confirmed by ¹ H NMR as in Fig. 1 1 . The obtained oligomer is named oligomer (9).

K ₂ C0 ₃ , D Ac/toluene

Example 10

The oligomer (8) (1 .269 g, 0.109 mmol), the oligomer (9) (0.731 g,

0.109 mmol) and K ₂ C0 ₃ (1 .6 g, 12 mmol) were added to DMSO (18 mL) and cyclohexane (9 mL), and was then dehydrated at 1 10 ^° C for 3 h. After removal of the cyclohexane, the mixture was heated to 1 10 ^° C, and after 48 h the product was precipitated in IPA, followed by a wash in water. The obtained multiblock copolymer (10) was dried in a vacuum oven at 60 ^° C overnight (yield: 92%, IEC: 2.1 1 meq/g determined by titration).

The multiblock copolymer (10) (1 .0 g) was added to acetic acid (20 mL), sulfuric acid (2.6 mL) and hydrogen peroxide (35% in water, 2.3 mL) and kept at 30 ^° C for 2 days, followed by at 1 10 ^° C for 30 min. After precipitation in IPA, the oxidized multiblock copolymer (11 ) was obtained and collected by a wash in water and drying in a vacuum oven at 60 ^° C overnight (yield: 80%, IEC: 1 .80 meq/g determined by titration).

Example 1 1

The hydration number per sulfonic acid group in the membranes of copolymers (10) and (11) was measured by the weight difference before and after soaking in water with a control of temperature, as shown in Fig. 13, with compared to Nafion and copolymer (2). As a result, both multiblock copolymers showed larger water uptakes than polymer 2 inspite of the similar IEC values.

The oxidized multiblock copolymer (11 ) showed a less water uptake than the non-oxidized multiblock copolymer (10), due to the change of sulfur ether bonds to sulfone bridges, resulting in a stiffer structure.

Example 12

The humidity dependence of proton conductivity of multiblock copolymer (10) and (11) was evaluated in a range 30-90 %RH at 80 ^° C, in references to Nafion and copolymer (2). Thanks to the higher water uptake as shown in Fig. 13, the proton conductivities of both multiblock copolymers were much higher than that of copolymer (2) and excellently comparable to that of Nafion in all range of RH. Despite the lower IEC value after oxidation, copolymer (11) showed a better proton conductivity than copolymer (10) perhaps due to an enhancement of acidity and/or a mechanism change of retaining water by forming sulfone bridges from thioether bonds.

Examples showing ways of preparing polymeric material comprising the herein disclosed structural elements in the backbone of the material

Example 13 - Building-up sulfonated macromonomer

An example how a macromonomer may be prepared is shown in Scheme A.

Scheme A: Synthetic pathway for building-up macromonomers

Disulfonated diaryl sulfone, so called SDCDPS, is reacted with 4- chlorobenzenethiol for a general condensation reaction in the presence of K2CO3 in DMAc. After the reaction and the purification, the product is oxidized to convert sulfur to sulfone bridges, by hydrogen peroxide. Then, it is additionally sulfonated by fuming sulfuric acid, followed by a purification. In this case, the obtained product is tetrasulfonated tetraaryl disulfone dihalide monomer. The process of alternating condensation and sulfonation may be repeated for the preparation of further extended macromonomers.

Example 14 - Sulfonated macromonomer with a long alkyl spacer

Scheme B shows an example of how a sulfonated macromonomer with a long alkyl spacer may be prepared. Scheme B: Synthetic pathway for macromonomers with a long pendant aliphatic sulfonate

Butane sultone

After the formation of a lithiated macromonomer by n-BuLi,

butanesultone is added via a ring opening to be replaced with a lithium, resulting in tetra-butanesulfonated tetraaryl disulfone dihalide macromonomer in this case.

Example 15 - Sulfonated macromonomer with a short alkyl spacer

Scheme C shows a possible synthetic pathway to attain a sulfonated macromonomer with a short alkyl spacer.

Scheme C: Synthetic pathway for macromonomers with a short pendant aliphatic sulfonate

S0 ₃ Na S0 ₃ Na

lodo methane is replaced with lithium by a displacement of iodine, resulting in a methylated macromonomer, after the formation of litihated monomer derivative. Then, a bromination by N-bromosuccinimide (NBS) or Br ₂ is conducted to brominates the methyl moiety. The bromines in the macromonomer are reacted with Na ₂ S0 ₃ , leading to a formation of

tetramethylsulfonated tetraaryl disulfone dihalide monomer in the present case. This approach may also enable a preparation, especially via metalation, of longer ionic monomers, since such methyl functionals may improve a solubility in THF that is an efficient solvent for metalation, in addition to that they may not cause a synthetic problem during condensation.

The above described monomers (1 ,2,3) may be incorporated into a polymer chain in combination with other co-monomers, such as diol(s), dithiol(s) and/or another type of dihalide via K ₂ C0 ₃ -mediated

polycondensation. Practical examples for preparation of monomers and (co)polymers has been shown below. Examples showing ways of preparing polymeric material comprising the herein disclosed structural elements in the side chains of the material

Example 16 - Disulfonated monomer via SOa

Scheme D shows one way how to attain a disulfonated diaryl sulfone halide monomer for a side chain type structure. By way of fuming sulfuric acid as a sulfonation reagent, two sulfonic acids are selectively attached to the mefa-positions to the sulfone bridge.

Scheme D: Synthesis of mono-halide monomer with two sulfonic acids in the meta-positions to the sulfone bridges

Example 17 - Disulfonated monomer via lithiation

As shown in Scheme E, the lithiation-sulfination-oxidation enables the sulfonic acid to be located in the o/ffro-positions to the sulfone bridges.

Scheme E: Synthesis of mono-halide monomer with two sulfonic acids in the ortho-positions to the sulfone bridges

Example 18 - Building-up sulfonated macromonomer via SOa

An example how a macromonomer may be prepared is shown in Scheme F. The approach is the same as in Scheme A shown above.

Scheme F: Synthetic approach to the trisulfonated macromonomer via

S0 ₃

Example 19 - Building-up sulfonated macromonomer via metalation

In addition to a condensation reaction, a lithiation-sulfination-oxidation may be performed in order to attach sulfonic acids in the o/ffro-positions to the sulfone bridges and the fluorines, as shown in Scheme G. In the final step, oxidization is used to activate the halogen for a subsequent condensation reaction.

Scheme G: Synthetic approach to the trisulfonated macromonomer via metalation

The above-mentioned monomers may be used either for a preparation of dihalide or di(thi)ol monomers towards side chain type (co)polymers as shown in Example 20, or to post-modify a functional polymer as shown in Example 21 .

Example 20 - Sulfonated dihalide monomer

Scheme H shows a synthetic pathway that may be used to prepare dihalide and dithiolated monomers for the subsequent polymerization.

Scheme H: Sulfonated dihalide monomer

A sulfur-containing dihalide side chain type monomer is prepared via condensation. Then, lithiation-sulfination is conducted to result in a sulfinated compound. The oxidation may selectively take place only to sulfinates by choosing water as a solvent with hydrogen peroxide. If acetic acid with or without sulfuric acid is selected as the solvent instead of water or after the oxidation in water, the thioether is also oxidized to sulfone in order to activate the dihalide for the polycondensation. If the thioether is still remained in the monomer, it may serve to replace halogen with thiol, for example, since the nucleophile property of thiols may be sufficient enough for reaction with any dihalide monomer. These above mentioned side chain type monomers may be incorporated into a polymer by polycondensation or coupling

polymerization.

Although this case describe the process starting with a non-ionic monomer, it is also possible to use pre-made sulfonated monomer for the same procedure. In addition to 2,6-dichlorothiophenol, any thiophenol with different orientations of dihalide is possible. As well, dihalogenated benzene, such as 1 ,3-difluorobenzene, may be available in order to directly prepare a side chain type dihalide monomer, by way of lithiation that produces a sulfinated dihalide monomer capable of reacting with a monohalide monomer. Example 21 - Post-modification using sulfonated monomer onto functional polymer

Scheme I shows a synthetic pathway that may be used to prepare side chain type polymer structure. For instance, a hydroxyl- or a thiol-functional polymer is reacted with them via condensation, resulting in a side chain type polymer structure.

Scheme I: Synthetic pathway towards homopolymer with sulfonated units as the side chain.

DCDPS and methoxy benzene diol are polycondensed with K2CO3 in an aprotic solvent towards hydroxylated poly(ether sulfone)s after the

deprotection reaction for example by BBr ₃ . For preparation of thiol-functional derivatives, Λ/,Λ/' -dimethyl thiocarbamoyi chloride is reacted with the hydroxyl groups with KOH in alcohol, followed by the rearrangement of the fluorine containing thiocarbamate by heat. Then, the sulfonated monohalide monomer is attached to either hydroxyl or thiol-derivative groups, resulting in a polymer with sulfonated units as the side chains. References

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