Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
METHODS AND COMPOSITIONS FOR FORMING FOOD-SAFE, UNIFORMLY-TEXTURED SURFACES, AND APPLICATIONS THEREOF
Document Type and Number:
WIPO Patent Application WO/2019/152707
Kind Code:
A1
Abstract:
A variety of food-safe, uniformly-textured surfaces for food packaging are provided as well as methods and compositions for forming the food-safe, uniformly-textured surfaces. The surfaces, methods, and compositions can be used for food-safe, uniformly-textured surfaces on various substrates such as PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags. The surfaces can stably support a lubricating liquid and, in some aspects, present nanoscale roughness and is substantially free of macro-scale roughness. The surfaces, compositions, and methods can be used in a variety of food packaging to provide non-stick surfaces for a food product such as ketchup, catsup, mustard, mayonnaise, syrup, honey, jelly, peanut butter, butter, chocolate syrup, shortening, butter, margarine, oleo, grease, dip, yogurt, or sour cream.

Inventors:
NAHUM, Tehila (Inc.85 Bolton Stree, Cambridge Massachusetts, 02140, US)
KIM, Philseok (Inc.85 Bolton Stree, Cambridge Massachusetts, 02140, US)
TREMELLING, Grant William (Inc.85 Bolton Stree, Cambridge Massachusetts, 02140, US)
Application Number:
US2019/016143
Publication Date:
August 08, 2019
Filing Date:
January 31, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ADAPTIVE SURFACE TECHNOLOGIES, INC. (85 Bolton Street, Cambridge, Massachusetts, 02140, US)
International Classes:
B32B27/06; B32B27/08; B32B27/18; B32B27/20; B32B27/30; B32B27/32
Attorney, Agent or Firm:
SEARS, Ph.D., John S. (THOMAS | HORSTEMEYER LLP, 3200 Windy Hill Road SE,Suite 1600, Atlanta Georgia, 30339, US)
Download PDF:
Claims:
We claim:

1. A surface for food packaging comprising:

(a) a substrate; and

(b) a base coat layer on a food-contacting surface of the substrate, the base coat layer comprising:

(i) about 15 parts by weight to about 45 parts by weight of an ethylene copolymer based upon a total weight of the base coat layer;

(ii) about 30 parts by weight to about 50 parts by weight of thermoplastic polyolefin based upon the total weight of the base coat layer;

(iii) about 20 parts by weight to about 40 parts by weight of hydrophobic nanoparticles based upon the total weight of the base coat layer; and

(iv) a substantially uniformly-textured outer surface.

2. A surface for food packaging comprising:

(a) a substrate;

(b) a base coat layer on a food-contacting surface of the substrate, the base coat layer comprising:

(i) about 15 parts by weight to about 45 parts by weight of an ethylene copolymer based upon a total weight of the base coat layer;

(ii) about 30 parts by weight to about 50 parts by weight of thermoplastic polyolefin based upon the total weight of the base coat layer;

(iii) about 20 parts by weight to about 40 parts by weight of hydrophobic nanoparticles based upon the total weight of the base coat layer; and

(iv) a substantially uniformly-textured outer surface; and

(c) an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid over layer.

3. The surface according to claim 1 or claim 2, wherein the ethylene copolymer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene butyl-acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene- vinyl acetate-maleic anhydride terpolymers, ethylene-propylene terpolymers, copolymers thereof, and blends thereof.

4. The surface according to claim 1 or claim 2, wherein the thermoplastic polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof.

5. The surface according to claim 1 or claim 2, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

6. The surface according to claim 1 or claim 2, wherein the ethylene copolymer is an ethylene vinyl acetate copolymer.

7. The surface according to claim 1 or claim 2, wherein the thermoplastic polyolefin is an isotactic polypropylene polymer.

8. The surface according to claim 1 or claim 2, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

9. The surface according to claim 1 or claim 2, wherein the hydrophobic nanoparticles have an average diameter of about 7 nm to about 200 nm and narrow particle size distribution.

10. The surface according to claim 1 or claim 2, wherein the surface, the ethylene copolymer, the thermoplastic polyolefin, and/or the hydrophobic nanoparticles are safe for food packaging.

11. A surface for food packaging comprising:

(a) a substrate; and

(b) a base coat layer, the base coat layer comprising:

(i) about 15 parts by weight to about 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 20% to about 50% by weight based upon a total weight of the ethylene-vinyl acetate copolymer;

(ii) about 30 parts by weight to about 50 parts by weight of isotactic polypropylene based upon the total weight of the base coat layer;

(iii) about 20 parts by weight to about 40 parts by weight of hydrophobic silica nanoparticles based upon the total weight of the base coat layer; and

(iv) a substantially uniformly-textured outer surface.

12. A surface for food packaging comprising:

(a) a substrate;

(b) a base coat layer, the base coat layer comprising:

(i) about 15 parts by weight to about 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 20% to about 50% by weight based upon a total weight of the ethylene-vinyl acetate copolymer;

(ii) about 30 parts by weight to about 50 parts by weight of isotactic polypropylene based upon the total weight of the base coat layer;

(iii) about 20 parts by weight to about 40 parts by weight of hydrophobic silica nanoparticles based upon the total weight of the base coat layer; and

(iv) a substantially uniformly-textured outer surface; and

(c) an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid over layer.

13. The surface according to any one of claims 1-2 and 11-12, wherein the edible oil is selected from the group consisting of soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, and combinations thereof.

14. The surface according to any one of claims 1-2 and 11-12, wherein the ethylene-vinyl acetate copolymer has a vinyl acetate content of about 28% to about 48% by weight based upon the total weight of the ethylene-vinyl acetate copolymer.

15. The surface according to any one of claims 1-2 and 11-12, wherein the hydrophobic nanoparticles have a narrow particle size distribution.

16. The surface according to any one of claims 1-2 and 11-12, wherein the nanoparticles are monodisperse.

17. The surface according to any one of claims 1-2 and 11-12, wherein the outer surface comprises nanoscale roughness that is substantially free of macro-scale roughness.

18. The surface according to any one of claims 1-2 and 11-12, wherein the outer surface is uniformly textured.

19. The surface according to any one of claims 1-2 and 11-12, wherein the substrate comprises polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and copolymers thereof, or blends thereof, including copolymers and blends with other polymers.

20. The surface according any one of claims 1-2 and 11-12, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

21. A composition for forming a surface for food packaging, the composition comprising:

(i) about 2 parts by weight to about 6 parts by weight of an ethylene copolymer based upon a total weight of the composition;

(ii) about 1 parts by weight to about 6 parts by weight of thermoplastic polyolefin based upon the total weight of the composition;

(iii) about 1 parts by weight to about 5 parts by weight of hydrophobic nanoparticles based upon the total weight of the composition;

(iv) about 60 parts by weight to about 90 parts by weight of toluene based upon the total weight of the composition; and

(v) about 5 parts by weight to about 25 parts by weight of xylene based upon the total weight of the composition.

22. The composition according to claim 21 , wherein the ethylene copolymer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene butyl-acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene-vinyl acetate- maleic anhydride terpolymers, copolymers thereof, and blends thereof.

23. The composition according to claim 21 , wherein the thermoplastic polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof.

24. The composition according to claim 21 , wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

25. The composition according to claim 21 , wherein the ethylene copolymer is an ethylene vinyl acetate copolymer.

26. The composition according to claim 21 , wherein the thermoplastic polyolefin is an isotactic polypropylene polymer.

27. The composition according to claim 21 , wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

28. The composition according to claim 21 , wherein the hydrophobic nanoparticles have an average diameter of about 7 nm to about 200 nm and narrow particle size distribution.

29. The composition according to claim 21 , wherein the ethylene copolymer, the thermoplastic polyolefin, the hydrophobic nanoparticles, the toluene and/or the xylene are safe for food packaging.

30. A composition for forming a surface for food packaging, the composition comprising:

(i) about 2 parts by weight to about 10 parts by weight of an ethylene copolymer based upon a total weight of the composition;

(ii) about 1 parts by weight to about 10 parts by weight of thermoplastic polyolefin based upon the total weight of the composition;

(iii) about 1 parts by weight to about 10 parts by weight of hydrophobic nanoparticles based upon the total weight of the composition;

(iv) about 60 parts by weight to about 90 parts by weight of a solvent based upon the total weight of the composition, wherein the solvent is safe for food packaging.

31. The composition according to claim 30, wherein the solvent comprises about 80 percent to about 95% by volume of toluene and about 5% to about 20% by volume of xylene based upon a total volume of the solvent.

32. The composition according to claim 21 or claim 30, wherein ethylene-vinyl acetate copolymer has a vinyl acetate content of about 28% to about 48% by weight based upon the total weight of the ethylene-vinyl acetate copolymer.

33. The composition according to claim 21 or claim 30, wherein the hydrophobic

nanoparticles have a narrow particle size distribution.

34. The composition according claim 21 or claim 30, wherein the nanoparticles are monodisperse.

35. The composition according to claim 21 or claim 30, wherein the composition is a dispersion that is stable at room temperature for a period of time from about 12 hours to about 48 hours.

36. The composition according to claim 21 or claim 30, wherein the composition is sprayable.

37. A method of making a surface for food packaging, the method comprising applying a composition according to any one of claims 21-35 to a surface of a substrate to form a base coat layer on the substrate.

38. The method according to claim 37, wherein the applying comprises spraying, brush painting, roller painting, dip coating, and/or spin coating the composition onto the surface.

39. The method according to claim 37, wherein the applying comprises spraying the composition onto the surface of the substrate.

40. The method according to any one of claims 37-39, further comprising drying the composition on the surface at a temperature of about 25°C for a period of time of about minutes to about 30 minutes or more.

41. The method according to any one of claims 37-39, wherein the substrate comprises polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), copolymers thereof, or blends thereof, including copolymers and blends with other polymers.

42. The method according to any one of claims 37-39, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

43. The method according to any one of claims 37-39, wherein the surface is a food contacting surface.

44. The method according to any one of claims 37-39, wherein the base coat layer has a substantially uniformly-textured outer surface.

45. The method according to any one of claims 37-39, wherein the base coat layer has an outer surface that has nanoscale roughness and is substantially free of macro-scale roughness.

46 The method according to any one of claims 37-39, wherein the base coat layer has an outer surface that is uniformly textured.

47. The method according to any one of claims 37-39, further comprising applying an edible oil to the outer surface, wherein the edible oil spontaneously wets and adheres to the outer surface to form a slippery liquid over layer.

48. A surface for food packaging made by a method according to any one of claims 37-47.

49. An article of food packaging comprising a food-contacting surface having a structure according to any one of claims 1-20.

50. An article of food packaging comprising a food-contacting surface made by a method according to any one of claims 37-47.

51. The article of food packaging according to claim 49 or claim 50, wherein the food packaging is for a food product selected from the group consisting of ketchup, catsup, mustard, mayonnaise, syrup, honey, jelly, peanut butter, butter, chocolate syrup, shortening, butter, margarine, oleo, grease, dip, yogurt, and sour cream.

Description:
METHODS AND COMPOSITIONS FOR FORMING FOOD-SAFE, UNIFORMLY-TEXTURED

SURFACES, AND APPLICATIONS THEREOF

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and the benefit of, co-pending U.S. provisional application entitled “METHODS AND COMPOSITIONS FOR FORMING FOOD-SAFE, UNIFORMLY-TEXTURED SURFACES, AND APPLICATIONS THEREOF” having serial no. 62/624,583, filed January 31 , 2018, the contents of which are incorporated by reference in their entirety.

TECHNICAL FIELD

[0002] The present disclosure generally relates to coatings and surfaces, and in particular to coatings and surfaces for the food industry.

BACKGROUND

[0003] While slippery liquid infused surfaces are expected to be useful in a variety of food packaging applications, they have yet to receive significant (if any) adoption in the industry. This may be due, at least in part, to some of the difficulties in fabricating suitable surfaces (surfaces that are robust and capable of retaining the slippery behavior for extended periods) in an economically viable manner, e.g. in a single step application. For example, it is difficult to produce surfaces that are free from pinning points (e.g. microscale texture, potential protrusion of larger length scale peaks of underlying solids above the liquid surface, incomplete coverage of the lubricant failing to form liquid overlayer around cracks where underlying solids can be exposed acting as pinning points), which leads to decreased performance and/or reduced lifetime for slippery liquid-infused porous surfaces. When dealing with food packaging and other products that will come into contact with food to be consumed, the types of materials that may be used are significantly more limited because the materials must generally be safe for contacting food, e.g. must be edible without harm to the consumer. This presents an additional challenge. Thus, compositions that are capable of forming such uniformly-textured surfaces and/or surfaces that are essentially free of pinning points with a single application step while still being safe for use in food packaging and other food-contacting products have not previously been disclosed. [0004] There remains a need for improved coating compositions for food and drug packaging as well as coatings and coated articles formed therefrom that overcome the aforementioned deficiencies.

SUMMARY

[0005] In various aspects, this disclosure is directed to surfaces for food packaging, compositions and methods for forming said surfaces, and packages including said surfaces, where the surfaces can be made entirely from components that are safe for food packaging. The surfaces are capable of supporting a stable liquid-infused porous surface, creating a slippery lubricating surface that can repel food products and foulants from the surface. The surfaces can be essentially free of pinning points leading to improved performance, low contact angle hysteresis on the surface, and improved service lifetime.

[0006] In one or more aspects, this disclosure provides surfaces for food packaging including a substrate and a base coat layer on a food-contacting surface of the substrate. The base coat layer can include about 15 parts by weight to about 45 parts by weight of an ethylene copolymer based upon a total weight of the base coat layer; about 30 parts by weight to about 50 parts by weight of thermoplastic polyolefin based upon the total weight of the base coat layer; about 20 parts by weight to about 40 parts by weight of hydrophobic nanoparticles based upon the total weight of the base coat layer; and a substantially uniformly-textured outer surface. The surface can further include an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer. In one or more aspects, the surface, the ethylene copolymer, the thermoplastic polyolefin, and/or the hydrophobic nanoparticles are safe for food packaging.

[0007] A variety of ethylene copolymers can be included. In some aspects, the ethylene copolymer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene butyl-acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene-vinyl acetate-maleic anhydride terpolymers, ethylene-propylene terpolymers, copolymers thereof, and blends thereof.

[0008] A variety of thermoplastic polyolefins can be included. In some aspects, the thermoplastic polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof. [0009] Suitable hydrophobic nanoparticles can include hydrophobic silica nanoparticles, e.g. having an average diameter of about 7 nm to about 200 nm and a narrow particle size distribution.

[0010] In one or more aspects, this disclosure provides surfaces for food packaging including a substrate and a base coat layer on a food-contacting surface of the substrate. The base coat layer can include about 15 parts by weight to about 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 20% to about 50% by weight based upon a total weight of the ethylene-vinyl acetate copolymer; about 30 parts by weight to about 50 parts by weight of isotactic polypropylene based upon the total weight of the base coat layer; about 20 parts by weight to about 40 parts by weight of hydrophobic silica nanoparticles based upon the total weight of the base coat layer; and a substantially uniformly-textured outer surface. The surface can further include an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid overlayer.

[0011] Suitable edible oils can include soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, or combinations thereof.

[0012] The surfaces can be on a variety of substrates, including polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and copolymers thereof, or blends thereof, including copolymers and blends with other polymers. In some aspects, the disclosure provides PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags having a surface described herein.

[0013] Other systems, methods, features, and advantages of surfaces for food packaging will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Further aspects of the present disclosure will be readily appreciated upon review of the detailed description of its various embodiments, described below, when taken in conjunction with the accompanying drawings.

[0015] FIG. 1 presents schematic diagrams of a side cross-sectional view of (left) a coating under loaded with particles such that the majority of the surface is binder, (center) a coating over-loaded with particles such that the particles are simply resting on the surface and can be brushed off easily, and (right) a good balance between the amount of binder and particles such that the particles are exposed at the surface but still remain trapped inside and/or within the matrix.

[0016] FIG. 2 presents schematic diagrams of a side cross-sectional view of a lubricated surface where (going from left to right) (a) there are insufficient particles in the formulation to create the surface texturing required to immobilize the lubricant; (b) there are a slightly increased particle loading where the lubricant is partially immobilized and the fouling agent can slide but over time will displace the lubricant, (c) a particle loading such that a stable lubricant layer is present that can completely repel the fouling agent, and (d) an over-loaded system that presents pinning points where the fouling agent can adhere to the particles extruding out of the lubricant layer. When the particle loading is such that a slippery liquid-infused porous surface at a thickness such that only lubricating liquid forms the surface above the functionalized, roughened surface (i.e., a smooth liquid interface is presented to the environment), the surface can completely repel the fouling agent.

[0017] FIG. 3 presents schematic diagrams of a side cross-sectional view of an embodiment of a functionalized, roughened surface of the present teachings showing that a bulk coating (left), which contains particles embedded inside the matrix, can present a new surface containing the desired particles and porosity at the surface after exposing the coating to mechanical abrasion (right).

[0018] FIG. 4 is a series of scanning electron microscope (SEM) images of surfaces prepared from ethylene vinyl acetate (EVA) and isotactic polypropylene (iPP) loaded with hydrophobic silica nanoparticles with different amounts of nanoparticle loading.

[0019] FIG. 5A is a graph of the contact angle measured for surfaces prepared from ethylene vinyl acetate (EVA) and isotactic polypropylene (iPP) loaded with hydrophobic silica nanoparticles for the particle pickup test with different nanoparticle loading and different PP/EVA ratio. FIG. 5B is a graph of the contact angle measured for surfaces prepared from ethylene vinyl acetate (EVA) and isotactic polypropylene (iPP) loaded with hydrophobic silica nanoparticles after removing the tape in the particle pickup test with different nanoparticle loading and different PP/EVA ratio.

[0020] FIGS. 6A-6C are graphs of the water droplet speed (centimeters per second) as a function of the nanoparticle loading for surfaces prepared from ethylene vinyl acetate (EVA) and isotactic polypropylene (iPP) loaded with hydrophobic silica nanoparticles and a vegetable oil lubricant. Each graph includes PP/EVA ratios of 0.5:1 , 0.75: 1 , and 1 : 1 for vegetable oil coatings spin coated at 1000 rpm (FIG. 6A), 5000 rpm (FIG. 6B), and 7000 rpm (FIG. 6C).

[0021] FIGS. 7A-7C are bar graphs of the weight (grams) of ethylene vinyl acetate (EVA) and isotactic polypropylene (iPP) films loaded with hydrophobic silica nanoparticles before (left) and after (right) submission in water for 48 hours as a function of the nanoparticle loading for films having an EVA:PP ratio of 1 : 1 (FIG. 7A), 1 :0.75 (FIG. 7B), and 1 :0.5 (FIG. 7C). ).

[0022] FIGS. 8A-8D are graphs of the toluene (triangles) and xylenes (squares) percentage during the evaporation of a solvent mixture containing a Toluene:Xylenes volume ratio 77:23 (FIG. 8A), 50:50 (FIG. 8B), 25:75 (FIG. 8C), and 86: 14 (FIG. 8D). For comparison purposes, the Toluene:Xylenes volume ratio of 77:23 is also included in FIG. 8D.

DETAILED DESCRIPTION

[0023] As previously described in international application PCT/US17/43915 entitled “Compositions And Methods For Creating Functionalized, Roughened Surfaces And Methods Of Creating Repellant Surfaces,” the contents of which are incorporated herein in their entirety, it was demonstrated that a substantially uniformly-textured or a uniformly-textured surface can be created in a single application without additional multi-step treatment (e.g. boiling water treatment and surface functionalization) and with better mechanical properties than previously known. Such surfaces, exhibiting uniform texturing without hierarchical texturing, can be better able to retain performance of a slippery liquid-infused surface because flat and smooth lubricant liquid overlayer can be better maintained due to the small and uniform pore/feature size on the surfaces.

[0024] The surfaces described in PCT/US17/43915 offer many advantages for a variety of coating applications, especially when they can be created in a single application step. However, the ability to create robust and uniformly-textured surfaces in a single application, comes with significant compromise. For example, factors that often must be controlled include composition of the nanoparticles and the binder, the compatibility of the solvent with the binder and the solvent’s ability to provide stable particle dispersions, the compatibility of the nanoparticles with the binder so that the nanoparticles may be dispersed in the final composition, the setting and/or curing time from application of the composition to its formation, and the evaporation profile of the solvent. Furthermore, if these surfaces are to be used for creating slippery liquid-infused surfaces, the surface chemistry must be compatible with the lubricating liquid so that it will spread and be retained on the surface in a robust manner.

[0025] While slippery liquid infused surfaces are expected to be useful in a variety of food packaging applications, they have yet to receive significant (if any) adoption in the industry. This may be due, at least in part, to some of the difficulties in fabricating suitable surfaces (surfaces that are robust and capable of retaining the slippery behavior for extended periods) in an economically viable manner, e.g. in a single step application. This is because, as demonstrated at least in PCT/US17/43915, there are several factors to control for when attempting to make the uniformly-textured surfaces described therein, surfaces that are robust and capable of retaining the slippery behavior for extended periods. For example, it is difficult to produce surfaces that are free from pinning points (e.g. microscale texture, potential protrusion of larger length scale peaks of underlying solids above the liquid surface, incomplete coverage of the lubricant failing to form liquid overlayer around cracks where underlying solids can be exposed acting as pinning points), which leads to decreased performance and/or reduced lifetime for slippery liquid-infused porous surfaces. When dealing with food packaging and other products that will come into contact with food to be consumed, the types of materials that may be used are significantly more limited because the materials must generally be safe for contacting food, e.g. must be edible without harm to the consumer. This presents an additional challenge. Thus, compositions that are capable of forming such uniformly-textured surfaces and/or surfaces that are essentially free of pinning points with a single application step while still being safe for use in food packaging and other food contacting products have not previously been disclosed.

[0026] As described herein, applicants have discovered compositions that can be applied in a single application step to form uniformly-textured surfaces that are still safe for use in food packaging and other food-contacting applications. The uniformly-textured surfaces formed therefrom are compatible with food-safe lubricants that can spontaneously wet and adhere to the surface to form a slippery liquid-infused surface. These uniformly-textured surfaces and slippery liquid-infused surfaces created therefrom are also provided herein. The surfaces can be used in a variety of food packaging and food-contacting applications, including but not limited to those provided herein. Methods of making the compositions and surfaces are also provided. [0027] Before the present disclosure is described in greater detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The skilled artisan will recognize many variants and adaptations of the embodiments described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0028] All publications and patents cited in this specification are cited to disclose and describe the methods and/or materials in connection with which the publications are cited. All such publications and patents are herein incorporated by references as if each individual publication or patent were specifically and individually indicated to be incorporated by reference. Such incorporation by reference is expressly limited to the methods and/or materials described in the cited publications and patents and does not extend to any lexicographical definitions from the cited publications and patents. Any lexicographical definition in the publications and patents cited that is not also expressly repeated in the instant specification should not be treated as such and should not be read as defining any terms appearing in the accompanying claims. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided could be different from the actual publication dates that may need to be independently confirmed.

[0029] Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described. Functions or constructions well-known in the art may not be described in detail for brevity and/or clarity. Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of nanotechnology, organic chemistry, material science and engineering and the like, which are within the skill of the art. Such techniques are explained fully in the literature.

[0030] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of“about 0.1 % to about 5%” should be interpreted to include not only the explicitly recited values of about 0.1 % to about 5%, but also include individual values (e.g., 1 %, 2%, 3%, and 4%) and the sub-ranges {e.g., 0.5%, 1.1 %, 2.2%, 3.3%, and 4.4%) within the indicated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase“x to y” includes the range from‘x’ to‘y’ as well as the range greater than‘x’ and less than‘y’ . The range can also be expressed as an upper limit, e.g.‘about x, y, z, or less’ and should be interpreted to include the specific ranges of‘about x’,‘about y’, and‘about z’ as well as the ranges of ‘less than x’, less than y’, and‘less than z’. Likewise, the phrase‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’,‘about y’, and‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In some embodiments, the term“about” can include traditional rounding according to significant figures of the numerical value. In addition, the phrase“about‘x’ to‘y’”, where‘x’ and‘y’ are numerical values, includes“about‘x’ to about‘y’”.

Definitions

[0031] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0032] The articles“a” and“an,” as used herein, mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of“a” and“an” does not limit the meaning to a single feature unless such a limit is specifically stated. The article“the” preceding singular or plural nouns or noun phrases denotes a particular specified feature or particular specified features and may have a singular or plural connotation depending upon the context in which it is used.

[0033] Throughout the application, where language such as having, including, or comprising is used to describe specific components or process steps, it is contemplated that other aspects exist that consist essentially of, or consist of the specific components or process steps.

[0034] The term "food packaging," as used herein, refers to anything used to contain a food item, and in particular for shipping from a point of manufacture to a consumer, and for subsequent storage and use by a consumer. Food packaging can be made of metal or non- metal, for example, glass, plastic, or laminate, and be in any form. An example of a suitable food packaging can include a plastic bottle, a laminate tube, or a metal can. The food packaging can include a food packaging plastic such as polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and copolymers thereof, or blends thereof, including copolymers and blends with other polymers. Food packaging plastics may also include one or more additives such as fillers, plasticizers, or stabilizers. Food packaging can include PET or HDPE containers or bottles, as well as PVC or LDPE sheets or bags. The food packaging can also include glass bottles or jars. The food packaging can refer to disposable food packaging which should be understood as something that is sealed so as to keep its contents free from deterioration until shortly after being opened by a consumer. The manufacturer will often identify the length of time during which the food or beverage will be free from spoilage, which typically ranges from several months to years. Thus, a "disposable food packaging" is distinguished from a reusable food packaging such as a storage container or bakeware in which a consumer might make and/or store food for a short period of time. As used herein, the term“shelf life” refers to the period of time that a food product remains saleable to retail customers and remains fit and safe for use or consumption. Changes including, but not limited to, oxidation, odor development, discoloration in addition to microbial changes can alter the shelf life of the food product.

[0035] The articles described herein will often have one or more food-contacting surfaces. For example, food packaging will generally contain one or more food-contacting surfaces such as the inside surfaces of a bottle or a bag or the side of a sheet or film that is designed to contact a food product. The term "food-contacting surface" refers to the surface of a package such as an inner surface of a food or beverage container that is in contact with, or intended for contact with, a food or beverage product. When referring to a substrate that may not be in final form, the term food contacting surface can refer to the surface of the substrate that is intended to be the food contacting surface in the final packaging as the term is used herein. Use of the term“food contacting surface” should not be construed overly literally to mean that the surface itself is actually contacting the food because, as will be seen herein, the surface may contain a coating or a base layer.

[0036] The term "edible," as used herein, refers to a non-toxic substance that is suitable for consumption by humans. The term“generally recognized as safe” or“GRAS”, as used herein, refers to substances generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, for example by general recognition of safety through scientific procedures under 21 C.F.R §170.30(b) or by general recognition of safety through experience based on common use in foods by a substantial history of consumption for food use under 21 C.F.R §170.30(c). GRAS substances can include those substances listed in 21 C.F.R. §182. Additionally, the materials listed in the EAFUS database are those items that are directly added into food in the United States and falls under multiple 21 CFR sub-sections particularly those related to human consumption.

[0037] The phrase“safe for food packaging”, as used herein, refers to substances that, based on sound scientific principals and procedures, are recognized as safe in the manner in which they are to be used where the substance will be contacting food that is intended for human consumption. Such recognition can include the likelihood of consumption of such substance and potential toxicity of the substance. Substances that are safe for food packaging can include those substances that are safe under the standard described in subsection 21 U.S.C. 348(c)(3)(A). Substances that are safe for food packaging can be those that are the subject of an effective premarket notifications for food contact substances submitted under 21 U.S.C. 348 (h)(1). Substances that are safe for food packaging can include those substances known as“indirect food additives” mentioned in Title 21 of the U.S. Code of Federal Regulations (21 CFR) Parts 174, 175, 176, 177, and 178 as well as those substances that are exempted from regulation as food additives in accordance with 21 CFR 170.39.

[0038] The term "substantially free" as used in this context means the reaction product and/or coating compositions contain less than 1000 parts per million (ppm), "essentially free" means less than 100 ppm and "completely free" means less than 20 parts per billion (ppb) of any of the above compounds or derivatives or residues thereof.

[0039] Unless otherwise indicated, the term "polymer" includes both homopolymers and copolymers (e.g., polymers of two or more different monomers) and oligomers. Similarly, unless otherwise indicated, the use of a term designating a polymer class is intended to include homopolymers, copolymers and graft copolymers.

[0040] The term“sprayable,” as used herein, means that the composition can be applied by a standard spraying device used in consumer products. In some aspects, the term sprayable means the composition can be sprayed using an air sprayer including an HPLV spray gun, an airless sprayer, or an air-assisted airless sprayer. In some aspects, a sprayable composition is one that can be sprayed at pressures of about 100 PSI, about 80 PSI, about 60 PSI, about 40 PSI, or less. In some aspects, the sprayable compositions can have a viscosity of about 150 mPas, about 100 mPas, about about 50 mPas, about 40 mPas, about 30 mPas, about 20 mPas, or less when measured with a plate/cone rotation rheometer at a shear rate of about 500 s _1 .

Compositions and methods for making uniformly-textured, food-safe surfaces, and uses thereof

[0041] As previously described in international application PCT/US17/43915 entitled “Compositions And Methods For Creating Functionalized, Roughened Surfaces And Methods Of Creating Repellant Surfaces,” substantially uniformly-textured or uniformly-textured surfaces can be formed from a one-pot spray formulation, which can be more advantageous than a hierarchically-textured surface for creating a slippery liquid-infused porous surface. Such surfaces can be created in a single application without additional multi-step treatment (e.g. boiling water treatment and surface functionalization) and with better mechanical properties than previously known. That is, a functionalized, roughened surface can be created that is substantially uniformly-textured such that the surface can immobilize a lubricating liquid (lubricant) to form a layer of liquid over and above the surface thereby presenting a smooth liquid interface with minimal, undesirable pinning points.

[0042] As described herein, substantially uniformly-textured or uniformly-textured surfaces can be formed via a one-pot spray formulation where the components and/or the surfaces formed are food-safe, e.g. are safe for food packaging. The compositions and the surfaces formed therefrom can be made from polymers, nanoparticles, and/or solvents that are edible, generally recognized as safe, safe, and/or safe for food packaging. At the same time, the choice of polymers, nanoparticles, and solvent balance a number of factors such as the composition of the nanoparticles and the binder, the compatibility of the solvent with the binder and the solvent’s ability to provide stable particle dispersions, the compatibility of the nanoparticles with the binder so that the nanoparticles may be dispersed in the final composition, the setting and/or curing time from application of the composition to its formation, and the evaporation profile of the solvent, and the surface chemistry of the base layer that is compatible with edible lubricating liquids that will spread and be retained on the surface in a robust manner.

[0043] Pinning points lead to a non-flat liquid interface conforming to the topography created by a larger length scale roughness than the nanoscale (e.g. microscale texture, potential protrusion of larger length scale peaks of underlying solids above the liquid surface, incomplete coverage of the lubricant failing to form liquid overlayer around cracks where underlying solids can be exposed acting as pinning points). Such exposed surfaces can act as a‘defect point’ where liquid can pin and contribute to increased contact angle hysteresis and as a starting point to dewet the pre-wet lubricant and eventually displace the lubricant.

[0044] Accordingly, the functionalized, roughened surface created from the compositions of the present teachings preferably is not a hierarchically-textured surface but rather a substantially uniformly-textured or a uniformly-textured surface. Such a uniformly-textured surface can be created using nanoparticles having a narrow particle size distribution such as a monodisperse population of nanoparticles. That is, a narrow particle size distribution can be described as monodispersed. By using a dispersion of suspended particles having a narrow particle size distribution, a porous or textured coating or film can be realized that has a smaller variation in its surface topography but maintains sufficient porosity to stably immobilize a lubricant within, on and over the porous coating.

[0045] In various embodiments, a narrow particle size distribution can refer to a population of nanoparticles having diameters with a standard deviation of about 90% from an average (or mean) diameter of the population of nanoparticles. In various embodiments, the narrow particle size distribution can have a standard deviation of about 80% from an average diameter, of about 75% from an average diameter, of about 70% from an average diameter, of about 60% from an average diameter, of about 50% from an average diameter, of about 40% from an average diameter, of about 30% from an average diameter, of about 20% from an average diameter, or less. In some aspects, the narrow particle size distribution refers to a population of nanoparticles having diameters within about 30 nm, within about 25 nm, within about 20 nm, within about 15 nm, within about 10 nm, within about 5 nm, or less from an average diameter of the population of nanoparticles.

[0046] With respect to creation of a substantially uniformly-textured surface rather than a hierarchically-textured surface, a hierarchically-textured surface typically refers to two different length scale features that form the porosity of the structure on the surface. The difference between the two different length scales should be at least an order of magnitude, i.e. , 10 1 or 10 times, different. Accordingly, with this hypothesis as a guide, to avoid creating a hierarchically- textured surface, the ratio of a primary feature size to a secondary feature size of solids in the composition such as nanoparticles can be less than about 10, less than about 9, less than about 8, less than about 7, less than about 6, less than about 5, less than about 4, less than about 3, or less than about 2. A primary feature size can be a particle size at the upper end of the particle size distribution range and a secondary feature size can be a particle size at the lower end of the particle size distribution.

[0047] Although under an order of magnitude difference between a primary feature size and a secondary feature size can provide a textured surface of the present teachings, often hierarchical structure features are discussed in terms of micro- and nano-scaled features, which size difference is three orders of magnitude, i.e., 10 3 or 1000 times, different. While such a large size difference in a particle size distribution range can create a hierarchically-textured surface, a grey area exists between this size difference and a one order of magnitude size difference. That is, a defined number as to where the cross-over occurs from one textured surface to the other is dependent on many different factors that influence the formation of the textured coating such as the composition of the nanoparticles and the binder, their compatibility with the solvent, the dispersion of the nanoparticles in the composition, the setting and/or curing time from application of the composition to its formation, and so on. Thus, a ratio of a primary size feature to a secondary size feature can be greater than 10 and can still provide a non-hierarchically-textured coating or surface, i.e., a substantially uniformly-textured coating, film or surface, using compositions and methods of the present teachings.

[0048] For example, in certain embodiments, the nanoparticles or binder can form agglomerates when applied to a substrate or surface. Agglomerates of nanoparticles or binder can be present in the compositions if they are not dispersed sufficiently or appropriately, or for other reasons such as the compatibility of the nanoparticles with the binder and/or the solvent. In such cases where agglomerates of nanoparticles or binder are present on the surface, a primary feature size can be the size of the agglomerates (e.g., an average size or a size at the upper end of the agglomerate size distribution range) and a secondary feature size can be the size of the nanoparticles or binders (e.g., an average size or a size at the lower end of the particle size distribution). In such cases, the ratio of a primary feature size to a secondary feature size can be greater than about 10, for example, greater than about 15, or greater than about 20 or greater than about 25, and provide a non-hierarchically-textured coating or surface, i.e., a substantially uniformly-textured coating or surface, using compositions and methods of the present teachings.

[0049] In these cases, without wishing to be bound to any particular theory, it is believed that because an agglomerate is composed of the nanoparticles in the composition, the surface topography of the agglomerate would be similar to the surface topography created by completely dispersed nanoparticles applied to a surface, although having the curvature of the agglomerate rather than conforming to the topography of the surface. Thus, while the largest size feature (e.g., the diameter of the agglomerate) would be larger than the largest nanoparticle size feature and could extend a greater distance from the underlying substrate or surface, a textured coating or film of the present teachings typically is not a mono-layer of nanoparticles but can contain many “layers” of nanoparticles from the surface of the substrate to the exposed surface of the coating. Consequently, a mixture of nanoparticles and agglomerates within the coating or film can present a substantially uniformly-textured surface similar to a textured surface created without any agglomerates present. Accordingly, the ratio of a primary feature size to a secondary feature size can be greater than about 10 and still provide a non-hierarchically-textured surface.

[0050] With respect to the stability of the lubricant overlayer, without wishing to be bound to any particular theory, while it is believed that the lubricant overlayer can be stabilized by the chemical affinity between it and the binder, an equal or greater amount of stability can be provided by having textured surface on top of chemical affinity. That is, a dominant factor stabilizing the lubricant overlayer can be the capillary force created by the functionalized, roughened surface texture, i.e. , porosity, of the present teachings.

[0051] For food-safe applications, it is desirable to use a lubricant that is edible in small amounts needed for forming the lubricant-infused surfaces. The chemistry of the base coat layer must therefore be chosen to be compatible with lubricants that are edible and/or safe for food packaging. In addition, a higher viscosity lubricant can assist in creating a more stable lubricant overlayer with greater lubricant retention on the surface. Furthermore, matching the viscosity of the lubricant being used to that of the fouling agent or liquid-to-be-repelled can improve the performance of the slippery liquid-infused porous surface’s anti-fouling characteristics. Finally, the formulation can be made such that the solution is low VOC or zero VOC as well as crack-free, for example, by tuning the solvent system of the composition.

[0052] Another factor in the preparation of the compositions of the present teachings is the particle loading or amount of nanoparticles in the composition. In some embodiments, a strong affinity between the nanoparticles and the binder is desired. In certain embodiments, when there is less affinity between the nanoparticles and the binder, a higher nanoparticle loading may be required. In some aspects, the nanoparticles are hydrophobic nanoparticles such as hydrophobic silica nanoparticles. Suitable nanoparticles can include, for example, fumed silica (Sigma Aldrich Co. LLC), HDS2, HDS3 (Nyacol Nano Technologies, Inc.), and HDK H15 and HDK H20 (Wacker Chemie AG). Suitable nanoparticles can include silica that has been surface functionalized to be hydrophobic via alkyl functional groups, polydimethylsiloxane functional groups, or combinations thereof.

[0053] The nanoparticles can have an average diameter between about 7 nm to about 1000 nm. For example, the average particle size of the nanoparticles can be about 7 nm to 200 nm, about 7 nm to about 50 nm, about 7 nm to about 25 nm, or about 7 nm to about 20 nm, about 40 nm to 150 nm, about 40 nm to 120 nm, about 200 nm to 500 nm, about 400 nm to 750 nm, or about 20 nm, about 50 nm, about 75 nm, about 100 nm, about 120 nm, about 150 nm, about 175 nm, about 200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm, about 450 nm, about 500 nm, about 600 nm, about 700 nm, about 800 nm, about 900 nm, or about 1000 nm.

[0054] Applicants have found that, the hydrophobic silica nanoparticles dispersed in a thermoplastic polyolefin resin, in particular an isotactic polypropylene resin, exhibit surfaces (chemistry and porosity/roughness) that can be spontaneously wet by edible lubricating oils to form a slippery liquid-infused porous surface. In addition, by blending the thermoplastic polyolefin resin with an ethylene copolymer, the base coat layers/films can be prepared that are durable and are spontaneously wet by these edible oils, such that they can potentially be used for food packaging and food contact applications where a slippery and non-stick surface is desirable. As will be seen in the examples below, by carefully optimizing the amount of thermoplastic polyolefin resin and ethylene copolymer, by carefully optimizing the nanoparticle loading, and by carefully optimizing the solvent conditions, applicants are able to generate high-quality, uniformly-textured surfaces for food packaging and food-contact applications that can support a slippery liquid- infused surface with lubricating fluids that are edible and/or safe for food packaging.

[0055] The thermoplastic polyolefin resin can include polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof. In some aspects, the thermoplastic polyolefin comprises, consists essentially of, and/or is a blend or copolymer of isotactic polypropylene. The thermoplastic polyolefin can have a density of about 0.9 to 0.95 grams per cubic centimeter (g/cm3). The thermoplastic polyolefin can have an average molecular weight of about 8,000-20,000, about 8,000-16,000, or about 10,000-14,000.

[0056] The ethylene copolymer can include ethylene-vinyl acetate copolymer, ethylene butyl- acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene-vinyl acetate-maleic anhydride terpolymers, copolymers thereof, and blends thereof. In some aspects, the ethylene copolymer comprises, consists essentially of, and/or is a blend or copolymer of ethylene-vinyl acetate copolymer. The ethylene-vinyl acetate copolymer can have a vinyl acetate content of about 20% to about 50% or about 28% to about 48% by weight based upon a total weight of the ethylene-vinyl acetate copolymer. The ethylene copolymer can have an average molecular weight of about 15000 grams per mole (g/m) to about 45000 g/m, about 15000 g/m to about 30000 g/m, or about 20000 g/m to about 30000 g/m.

[0057] The mechanical integrity and surface chemistry of the base coat layer will depend on a number of factors, including the proportions of the polymer binder(s) and the nanoparticles in the base coat layer. In some aspects, the thermoplastic polyolefin is present in the cured or dried base coat layer in an amount from about 10 parts by weight to about 60 parts by weight, about 15 parts by weight to about 50 parts by weight, about 15 parts by weight to about 45 parts by weight, about 20 parts by weight to about 40 parts by weight, or about 20 parts by weight to about 45 parts by weight based upon a total weight of the base coat layer. In some aspects, the ethylene copolymer is present in the cured or dried base coat layer in an amount about 20 parts by weight to about 60 parts by weight, about 30 parts by weight to about 50 parts by weight, about 30 parts by weight to about 40 parts by weight, about 25 parts by weight to about 40 parts by weight, or about 20 parts by weight to about 40 parts by weight based upon a total weight of the base coat layer. In some aspects, the hydrophobic nanoparticles are present in the cured or dried base coat layer in an amount from about 10 parts by weight to about 50 parts by weight, about 15 parts by weight to about 45 parts by weight, about 20 parts by weight to about 40 parts by weight, or about 24 parts by weight to about 36 parts by weight based upon a total weight of the base coat layer.

[0058] Compositions and methods are provided for making the surfaces described herein. The methods can include applying the roughening composition by one or more of spraying, brush painting, roller painting, dip coating, and spin coating the roughening composition. The methods can include removing the solvent from the roughening composition on the surface, for example, by evaporating the solvent. Removing the solvent from the roughening composition on the surface can include controlling the rate of removal of the solvent to provide a crack-free functionalized, roughened surface. Controlling the rate of removal of the solvent can include at least one of altering the solvent blend, altering the evaporation temperature, and altering the evaporation humidity.

[0059] The compositions can include about 2 parts by weight to about 10 parts by weight of an ethylene copolymer based upon a total weight of the composition; about 1 parts by weight to about 10 parts by weight of thermoplastic polyolefin based upon the total weight of the composition; about 1 parts by weight to about 10 parts by weight of hydrophobic nanoparticles based upon the total weight of the composition; and about 70 parts by weight to about 95 parts by weight of a solvent based upon the total weight of the composition, wherein the solvent is safe for food packaging. In some aspects, the composition contains about 2 parts by weight to about 8 parts by weight, about 2 parts by weight to about 6 parts by weight, about 2 parts by weight to about 4 parts by weight, or about 3 parts by weight to about 6 parts by weight of the ethylene copolymer based upon the total weight of the composition. In some aspects, the composition contains about 1 parts by weight to about 8 parts by weight, about 1 parts by weight to about 6 parts by weight, about 1 parts by weight to about 3 parts by weight, or about 3 parts by weight to about 6 parts by weight of the thermoplastic polyolefin based upon the total weight of the composition. In some aspects, the composition contains about 1 parts by weight to about 8 parts by weight, about 1 parts by weight to about 6 parts by weight, about 1 parts by weight to about 3 parts by weight, or about 3 parts by weight to about 6 parts by weight of the hydrophobic nanoparticles based upon the total weight of the composition. The thermoplastic polyolefin and the ethylene copolymer can be present in the composition at a ratio (weight thermoplastic polyolefin: weight ethylene copolymer) of about 1 :2.1 to about 1.2: 1 , about 1 :2 to about 1 :1 , about 0.8:1 to about 1 :0.8, about 1 :2 to about 1 : 1.3.

[0060] The compositions can include a solvent that is safe for food packaging. In some aspects, the composition includes about 60 parts by weight to about 95 parts by weight, about 65 parts by weight to about 90 parts by weight, about 70 parts by weight to about 90 parts by weight, about 70 parts by weight to about 95 parts by weight, about 90 parts by weight to about 95 parts by weight, about 85 parts by weight to about 90 parts by weight, or about 75 parts by weight to about 85 parts by weight of the solvent. The solvent can be a mixture of two, three, four, or more solvents. A primary consideration when selecting a solvent is compatibility. The solvent must be compatible with the binder while also providing stability for the particle dispersion. Should the solvent be incompatible with the particles or the binder then this leaves the possibility for the particles to re-aggregate or the binder to phase separate out of solution, resulting in an inhomogeneous mixture incapable of producing the proper texturing. A secondary consideration when selecting a solvent is evaporation rate and profile. By tuning the drying profile, the coating or film can set properly, not only exposing the nanoparticles but also improving the mechanical durability of the coating. An uncontrolled drying process can lead to the formation of cracks, simultaneously decreasing the mechanical durability of the film and compromising the uniform texturing required to maintain a stable lubricant overlayer. Accordingly, overall coating quality and functionality can rely on a properly tuned solvent system. The solvent can include a mixture of toluene and xylene. The solvent can include any one, any two, or all three of toluene, xylene, and d-limonene, optionally including one or more additional solvents. In some aspects, the drying profile (and therefore the surface) is improved with a solvent containing about 75% to about 95% toluene by volume, about 80% to about 95% toluene by volume, or about 80% to 90% toluene by volume based upon the total volume of the solvent. In some aspects, the drying profile (and therefore the surface) is improved with a solvent containing about 5% to about 25% xylene by volume, about 10% to about 25% xylene by volume, or about 5% to 20% xylene by volume based upon the total volume of the solvent.

[0061] The compositions can be a one-pot sprayable composition. The compositions can include a dispersion or suspension in with disaggregated nanoparticles are dispersed in the solvent and the polymer components dissolved in or emulsified within the solvent. In the methods of the present teachings, dispersing nanoparticles can include ultrasonicating nanoparticles in the solvent. The methods can include applying the roughening composition by one or more of spraying, brush painting, roller painting, dip coating, and spin coating the roughening composition. The methods can include removing the solvent from the roughening composition on the surface, for example, by evaporating the solvent. Removing the solvent from the roughening composition on the surface can include controlling the rate of removal of the solvent to provide a crack-free functionalized, roughened surface. Controlling the rate of removal of the solvent can include at least one of altering the solvent blend, altering the evaporation temperature, and altering the evaporation humidity. Spray coating can include the introduction of the coating composition into the inside of a preformed packaging container. Typical preformed packaging containers suitable for spray coating include food cans, beer and beverage containers, bottles, and the like. The spray preferably utilizes a spray nozzle capable of uniformly coating the inside of the preformed packaging container. The sprayed preformed container is then subjected to drying to remove the solvent and harden the coating.

[0062] A goal is to spray a one-pot formulation that cures or sets in such a way as to allow the particles to be exposed at the surface but not so much so that the binder is incapable of holding them in place (see FIG. 1). This is important for creating a system that is both mechanically robust while still presenting the proper texturing required for stabilizing a uniform lubricant overlayer (FIG. 2). The exact particle loading is dependent on the compatibility between the binder and the particles being used and can vary for any given system. Additionally, since the particles are exposed at the surface it is possible to tune the chemistry of the particles such that a greater affinity between the surface and the lubricant exists, helping further stabilize the lubricant overlayer. Furthermore, with a bulk coating, which contains particles embedded inside the matrix, the coating can present a new surface containing the desired particles and porosity at the surface after exposing the coating to mechanical abrasion (FIG. 3).

[0063] Examples of lubricating liquids or lubricants that can be useful include edible oils such as soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil and combinations thereof.

[0064] In another aspect, methods of creating a functionalized, roughened surface can generally include dispersing nanoparticles having a narrow particle size distribution in a solvent including a binder to form a roughening composition; applying the roughening composition to a surface; and removing the solvent from the roughening composition on the surface to form a coating including a functionalized, roughened surface. In the methods of the present teachings, dispersing nanoparticles can include ultrasonicating nanoparticles in the solvent, using a rotorstator to disperse the nanoparticles in the solvent, or other particle grinding and dispersing methods known in the art.

[0065] The present teachings also provide methods of creating a repellant surface. The methods can include forming a functionalized, roughened surface according to the present teachings; and applying a lubricating liquid to the functionalized, roughened surface. The lubricating liquid can have a chemical affinity for the functionalized, roughened surface such that, at atmospheric pressure, the lubricating liquid is substantially immobilized in, on and over the functionalized, roughened surface, without dewetting from the substrate, to form a repellant surface.

[0066] The methods can include applying a lubricating liquid by applying the lubricating liquid in a solvent. The repellant surface can be a smooth liquid surface of the lubricating liquid over and above the functionalized, roughened surface. In particular methods, the lubricating liquid can have a chemical affinity for the nanoparticles and/or the binder. In certain methods, the chemical affinity of the functionalized, roughened surface for the lubricating liquid can be greater than the chemical affinity of the functionalized, roughened surface for a foreign material to be repelled by the repellant surface. In some embodiments, the viscosity ratio of the lubricating liquid to that of a foreign material to be repelled by the repellant surface is close to 1 , 1 +/- 0.25, or 1 + /- 0.5. In various methods, the lubricating liquid is immiscible with a foreign material to be repelled by the repellant surface. The methods of the present teachings can further include delivering additional lubricating liquid to the repellant surface.

EXAMPLES

[0067] Now having described the embodiments of the present disclosure, in general, the following Examples describe some additional embodiments of the present disclosure. While embodiments of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit embodiments of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of embodiments of the present disclosure.

Example 1. Evaluation of surface formation

[0068] Styrene Butadiene Copolymer (SBC) surface formation was evaluated for use in forming food-grade surface. Part A was prepared by dissolving Styrene Butadiene Copolymer (SBC) in toluene solvent at room temperature for 2 hours. Part B was prepared by ultrasonicating Hydrophobic Silica nanoparticles (NP) in Toluene for 1 min to get a stable dispersion. Then part A was added to part B and ultrasonicated for 2 min to get the final composition. Varying amounts of Part A and Part B were combined to yield the final weight percentages in Table 1. Films were prepared via spraying technique using HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 pL droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 1.

Table 1. Solution composition, contact angle measurements, and coating and film quality for SBC polymer films.

[0069] Observing the poor durability of the SBC films, films were prepared using Ethylene Vinyl Acetate (28 wt% VA content) in Toluene solvent. A medical grade (USP class 6) EVA, from Celanese was used for these examples.

[0070] Part A was prepared by dissolving EVA in toluene solvent at 70°C for 1 hour. Part B was prepared by sonicating Hydrophobic Silica nanoparticles (NP) in Toluene for 1 min to get a stable dispersion. Then part A was added to part B and sonicated for 2 min to get the final composition. Varying amounts of Part A and Part B were combined to yield the final weight percentages in Table 2. Films were prepared via spraying technique using HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 mI_ droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 2.

Table 2. Solution composition, contact angle measurements, and coating and film quality for EVA polymer films.

[0071] Although more durable than the SBC films, the EVA films still exhibited durability that was not enough for coatings applications. In an effort to further improve the film quality, the SBC films were modified by replacing the nanoparticles with Carnauba wax powder. The solution was prepared using probe sonication and sprayed warm (clear yellow solution) using HVLP gun with 40 psi air pressure.

[0072] Part A was prepared by dissolving SBC in toluene solvent. Part B was prepared by sonicating Carnauba wax powder in Acetone to get a stable dispersion. Then part A was added to part B and ultrasonicated for 5 min to get the final composition at elevated temperature such that the solution is clear. Varying amounts of Part A and Part B were combined to yield the final weight percentages in Table 3. Films were prepared via HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 pL droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 3. Table 3. Solution composition, contact angle measurements, and coating and film quality for SBC polymer films.

[0073]

[0074] Although film quality improves when switching to Carnauba wax, the contact angle was not high enough (<150°), and there was no nanoroughness visible in the SEM images without the NPs. As a result, rapeseed vegetable oil did not spread on these surfaces.

[0075] The surfaces were tested by changing from SBC to an isotactic polypropylene (iPP) binder. Part A was prepared by dissolving iPP in xylenes solvent in a silicone oil bath at 100°C overnight. Part B was prepared by sonicating Hydrophobic Silica nanoparticles (NP) in Toluene for 1 min to get a stable dispersion. Then part A was added to part B and sonicated for 2 min to get the final composition. Varying amounts of Part A and Part B were combined to yield the final weight percentages in Table 4. Films were prepared via HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 pl_ droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 4.

Table 4. Solution composition, contact angle measurements, and coating and film quality for iPP polymer films.

[0076] Films were prepared using iPP as a co-binder with EVA. EVA was dissolved in toluene at 70°C for 1 hour. NPs were dispersed in toluene using sonication for 1 min to get a stable dispersion. iPP was dissolved in xylenes in a silicone oil bath at 100°C overnight . Before mixing iPP with EVA and the NPs dispersion, it was very difficult to get solutions of iPP at room temperature without recrystallization. Once the components were combined together, a stable system at room temperature was obtained that can be further processed. Each of the components was combined to yield the final weight percentages shown in Table 5. Films were prepared via HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 mI_ droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 5. EVA and PP are chemically compatible. EVA can slow down the crystallization of polypropylene. EVA showed better film durability with the hydrophobic silica NPs than SBC polymer. These compositions yielded successful nanoporous films in terms of spreading of vegetable oil on the surface.

Table 5. Solution composition, contact angle measurements, and coating and film quality for EVA/iPP polymer films.

[0077]

Example 2. Impact of nanoparticle loading on surface compositions

[0078] The impact of the nanoparticle loading on the surface energy, roughness, and film quality was investigated. EVA/iPP films were prepared as described above with varying amounts of NPs. Each of the components was combined to yield the final weight percentages in Table 6. Films were prepared via HVLP spray gun with air pressure of 40 psi. Contact angle measurements were performed using Biolin Scientific goniometer using a 5 mI_ droplet of deionized water. Films were inspected for the spreading ability of rapeseed vegetable oil on the surface as well as for film quality and durability. All results are reported in Table 6.

Table 6. Solution composition, contact angle measurements, and coating and film quality for EVA/iPP polymer films as a function of nanoparticle loading.

[0079] No observable difference in film quality was detected. All films exhibited large contact angles and good quality films. The SEM images for the range of 2.78 to 3.6 wt% NPs are depicted in FIG. 4.

Example 3. Roughness and durability of surfaces

[0080] For good slippery liquid-infused porous surface formation it is important to avoid macro roughness since these are potentially pinning point for the foulants that are to be repelled. In order to solve the roughness, iPP loading was decreased (in previous examples iPP:EVA ratio was 1 : 1) to see if it helps to make a smoother film. Since the film loses its durability in the absence of iPP, particle pick up tests were performed. As no difference between the NPs loading (2.78 to 3.6 wt%) was observed in Example 2, all the samples were examined for particle pick up test. For the particle pick up testing, the initial contact angle of the surface is measured, then a piece of scotch tape is adhered on the surface and then removed. If particles adhere to the tape, then coating is determined as failed. If particles didn’t adhere to the tape, the contact angle is measured again to ensure the NPs are held by the binders and the contact angle is stable. The results are depicted in Table 7.

Table 7. Solution composition and results of particle pickup test for varying the ratio of EVA to iPP and the amount of NPs loading of EVA/iPP polymer films

[0081] All samples with iPP loading lower than that of EVA failed in particle pick up test since the particles adhere to the tape and be removed from the coating. When iPP and EVA loading is the same (by wt%), particles are being held by the coating and no change in the contact angle was observed. The only exception was for 2.78 wt% NPs loading that failed the particle pick up test. The results are also plotted in FIGS. 5A-5B.

Example 4. Water droplet moving speed tests of lubricated surfaces

[0082] Water droplet speed tests were performed to evaluate the surfaces for forming slippery liquid-infused porous coatings using food grade oils as a liquid lubricant. All samples were lubricated with rapeseed vegetable oil to get different LOL thickness. LOL 1 (thicker) - spin coat at 1000 rpm for 1 min, LOL 2 (moderate) - spin coat at 5000 rpm for 1 min, LOL 3 (thinner) - spin coat at 7000 rpm for 1 min. A 15 microliter water droplet was placed on the sample tilted to 15 degrees. The time it takes for the drop to pass a 4 cm distance was recorded. The results are depicted in FIGS. 6A-6C. In general, as the LOL thickness decreases, the water droplet speed decreases. This trend was observed in all the samples. EVA:iPP ratio of 1 :0.5 showed faster droplet speed.

Example 5. Water submersion test

[0083] All samples were submerged in water for 48 hours. Their weight before and after submersion was recorded to see if the coating absorbs water over time. The results are shown in FIGS. 7A-7C. No change in weight was observed for EVA:iPP ratio of 1 :1 with different NPs loading (FIG. 7A). No change in weight was observed for EVA:iPP ratio of 1 :0.75 with different NPs loading (FIG. 7B). No change in weight was observed for EVA:iPP ratio of 1 :0.5 with different NPs loading (FIG. 7C). Therefore all the coatings tested did not show any signs of absorbing water at least for 48 hours when submerged.

Example 6. Changing Toluene:Xylenes volume ratio to achieve smoother surface finish

[0084] The original Toluene:Xylenes volume ratio was 77:23 (FIG. 8A), but the resultant surface finish of the films formed was not good enough and was very rough. Upon changing Toluene:Xylenes volume ratio to 50:50 (FIG. 8B), the surface finish was not significantly improved. Upon changing Toluene:Xylenes volume ratio to 25:75, the surface became very powdery and the desired film quality was lost (FIG. 8C). Increasing xylenes loading made the surface rougher and powdery. Toluene evaporates faster than xylenes. Therefore at the final stages of drying of the film, xylenes is the majority of the solvent remaining in the drying film. It is desirable to find a way to increase toluene in the final stage of film formation to achieve a smooth and high quality finish of the resultant film. One way to solve the problem is to eliminate xylenes from the system. Unfortunately, iPP did not completely dissolve in toluene even after 3 days at 110°C. In an effort to combat this, the Toluene loading was significantly increased to keep more toluene in the system at the later stage of film drying process. Therefore the Toluene:xylenes volume ratio was increased up to 86:14% in the specific examples describe herein. As shown in the evaporation profile graph, increasing Toluene:Xylenes volume ratio can further push the cross-over point toward the later stage of film drying. (FIG. 8D) Notwithstanding the specific examples shown here, one can obviously further optimize the ratio of Toluene:Xylenes in this system depending on the application conditions and methods selected.

[0085] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations, and are set forth only for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above- described embodiments of the disclosure without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure.

[0086] The various aspects of the invention will be better understood by reading the following aspects, which should not be confused with the claims.

[0087] Aspect 1. A surface for food packaging comprising: (a) a substrate; and (b) a base coat layer on a food-contacting surface of the substrate, the base coat layer comprising: (i) about 15 parts by weight to about 45 parts by weight of an ethylene copolymer based upon a total weight of the base coat layer; (ii) about 30 parts by weight to about 50 parts by weight of thermoplastic polyolefin based upon the total weight of the base coat layer; (iii) about 20 parts by weight to about 40 parts by weight of hydrophobic nanoparticles based upon the total weight of the base coat layer; and (iv) a substantially uniformly-textured outer surface.

[0088] Aspect 2. A surface for food packaging comprising: (a) a substrate; (b) a base coat layer on a food-contacting surface of the substrate, the base coat layer comprising: (i) about 15 parts by weight to about 45 parts by weight of an ethylene copolymer based upon a total weight of the base coat layer; (ii) about 30 parts by weight to about 50 parts by weight of thermoplastic polyolefin based upon the total weight of the base coat layer; (iii) about 20 parts by weight to about 40 parts by weight of hydrophobic nanoparticles based upon the total weight of the base coat layer; and (iv) a substantially uniformly-textured outer surface; and (c) an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid over layer.

[0089] Aspect 3. The surface according to any one of Aspects 1-20, wherein the ethylene copolymer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene butyl-acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene-vinyl acetate-maleic anhydride terpolymers, ethylene-propylene terpolymers, copolymers thereof, and blends thereof. [0090] Aspect 4. The surface according to any one of Aspects 1-20, wherein the thermoplastic polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof.

[0091] Aspect 5. The surface according to any one of Aspects 1-20, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

[0092] Aspect 6. The surface according to any one of Aspects 1-20, wherein the ethylene copolymer is an ethylene vinyl acetate copolymer.

[0093] Aspect 7. The surface according to any one of Aspects 1-20, wherein the thermoplastic polyolefin is an isotactic polypropylene polymer.

[0094] Aspect 8. The surface according to any one of Aspects 1-20, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

[0095] Aspect 9. The surface according to any one of Aspects 1-20, wherein the hydrophobic nanoparticles have an average diameter of about 7 nm to about 200 nm and narrow particle size distribution.

[0096] Aspect 10. The surface according to any one of Aspects 1-20, wherein the surface, the ethylene copolymer, the thermoplastic polyolefin, and/or the hydrophobic nanoparticles are safe for food packaging.

[0097] Aspect 11. A surface for food packaging comprising: (a) a substrate; and (b) a base coat layer, the base coat layer comprising: (i) about 15 parts by weight to about 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 20% to about 50% by weight based upon a total weight of the ethylene-vinyl acetate copolymer; (ii) about 30 parts by weight to about 50 parts by weight of isotactic polypropylene based upon the total weight of the base coat layer; (iii) about 20 parts by weight to about 40 parts by weight of hydrophobic silica nanoparticles based upon the total weight of the base coat layer; and (iv) a substantially uniformly-textured outer surface.

[0098] Aspect 12. A surface for food packaging comprising: (a) a substrate; (b) a base coat layer, the base coat layer comprising: (i) about 15 parts by weight to about 45 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 20% to about 50% by weight based upon a total weight of the ethylene-vinyl acetate copolymer; (ii) about 30 parts by weight to about 50 parts by weight of isotactic polypropylene based upon the total weight of the base coat layer; (iii) about 20 parts by weight to about 40 parts by weight of hydrophobic silica nanoparticles based upon the total weight of the base coat layer; and (iv) a substantially uniformly-textured outer surface; and (c) an edible oil spontaneously wetting and adhering to the outer surface of the base coat layer to form a slippery liquid over layer.

[0099] Aspect 13. The surface according to any one of Aspects 1-20, wherein the edible oil is selected from the group consisting of soybean oil, canola oil, rapeseed oil, corn oil, sunflower oil, high oleic sunflower oil, coconut oil, safflower oil, peanut oil, palm oil, super olein oil, cottonseed oil, ground nut oil, olive oil, rice bran oil, safflower oil, grapeseed oil, walnut oil, flaxseed oil, macadamia nut oil, and combinations thereof.

[0100] Aspect 14. The surface according to any one of Aspects 1-20, wherein the ethylene- vinyl acetate copolymer has a vinyl acetate content of about 28% to about 48% by weight based upon the total weight of the ethylene-vinyl acetate copolymer.

[0101] Aspect 15. The surface according any one of Aspects 1-20, wherein the hydrophobic nanoparticles have a narrow particle size distribution.

[0102] Aspect 16. The surface according to any one of Aspects 1-20, wherein the nanoparticles are monodisperse.

[0103] Aspect 17. The surface according to any one of Aspects 1-20, wherein the outer surface comprises nanoscale roughness that is substantially free of macro-scale roughness.

[0104] Aspect 18. The surface according to any one of Aspects 1-20, wherein the outer surface is uniformly textured.

[0105] Aspect 19. The surface according to any one of Aspects 1-20, wherein the substrate comprises polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and copolymers thereof, or blends thereof, including copolymers and blends with other polymers.

[0106] Aspect 20. The surface according to any one of Aspects 1-20, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PP bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0107] Aspect 21. A composition for forming a surface for food packaging, the composition comprising: (i) about 2 parts by weight to about 6 parts by weight of an ethylene copolymer based upon a total weight of the composition; (ii) about 1 parts by weight to about 6 parts by weight of thermoplastic polyolefin based upon the total weight of the composition; (iii) about 1 parts by weight to about 5 parts by weight of hydrophobic nanoparticles based upon the total weight of the composition; (iv) about 60 parts by weight to about 90 parts by weight of toluene based upon the total weight of the composition; and (v) about 5 parts by weight to about 25 parts by weight of xylene based upon the total weight of the composition.

[0108] Aspect 22. The composition according to any one of Aspects 21-36, wherein the ethylene copolymer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene butyl-acrylate copolymer, ethylene ethyl-acrylate copolymer, ethylene methyl-acrylate copolymer, ethylene-vinyl acetate-maleic anhydride terpolymers, copolymers thereof, and blends thereof.

[0109] Aspect 23. The composition according to any one of Aspects 21-36, wherein the thermoplastic polyolefin is selected from the group consisting of polyethylene, polypropylene, polymethylpentene, polybutene-1 , copolymers thereof, and blends thereof.

[0110] 24. The composition according to any one of Aspects 21-36, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

[0111] Aspect 25. The composition according to any one of Aspects 21-36, wherein the ethylene copolymer is an ethylene vinyl acetate copolymer.

[0112] Aspect 26. The composition according to any one of Aspects 21-36, wherein the thermoplastic polyolefin is an isotactic polypropylene polymer.

[0113] Aspect 27. The composition according to any one of Aspects 21-36, wherein the hydrophobic nanoparticles are hydrophobic silica nanoparticles.

[0114] Aspect 28. The composition according to any one of Aspects 21-36, wherein the hydrophobic nanoparticles have an average diameter of about 7 nm to about 200 nm and narrow particle size distribution.

[0115] Aspect 29. The composition according to any one of Aspects 21-36, wherein the ethylene copolymer, the thermoplastic polyolefin, the hydrophobic nanoparticles, the toluene and/or the xylene are safe for food packaging.

[0116] Aspect 30. A composition for forming a surface for food packaging, the composition comprising: (i) about 2 parts by weight to about 10 parts by weight of an ethylene copolymer based upon a total weight of the composition; (ii) about 1 parts by weight to about 10 parts by weight of thermoplastic polyolefin based upon the total weight of the composition; (iii) about 1 parts by weight to about 10 parts by weight of hydrophobic nanoparticles based upon the total weight of the composition; (iv) about 60 parts by weight to about 90 parts by weight of a solvent based upon the total weight of the composition, wherein the solvent is safe for food packaging.

[0117] Aspect 31. The composition according to any one of Aspects 21-36, wherein the solvent comprises about 80 percent to about 95% by volume of toluene and about 5% to about 20% by volume of xylene based upon a total volume of the solvent.

[0118] Aspect 32. The composition according to any one of Aspects 21-36, wherein ethylene- vinyl acetate copolymer has a vinyl acetate content of about 28% to about 48% by weight based upon the total weight of the ethylene-vinyl acetate copolymer.

[0119] Aspect 33. The composition according to any one of Aspects 21-36, wherein the hydrophobic nanoparticles have a narrow particle size distribution.

[0120] Aspect 34. The composition according to any one of Aspects 21-36, wherein the nanoparticles are monodisperse.

[0121] Aspect 35. The composition according to any one of Aspects 21-36, wherein the composition is a dispersion that is stable at room temperature for a period of time from about 12 hours to about 48 hours.

[0122] Aspect 36. The composition according to any one of Aspects 21-36, wherein the composition is sprayable.

[0123] Aspect 37. A method of making a surface for food packaging, the method comprising applying a composition according to any one of Aspects 21-36 to a surface of a substrate to form a base coat layer on the substrate.

[0124] Aspect 38. The method according to any one of Aspects 37-47, wherein the applying comprises spraying, brush painting, roller painting, dip coating, and/or spin coating the composition onto the surface.

[0125] Aspect 39. The method according to any one of Aspects 37-47, wherein the applying comprises spraying the composition onto the surface of the substrate. [0126] Aspect 40. The method according to any one of Aspects 37-47, further comprising drying the composition on the surface at a temperature of about 25°C for a period of time of about 15 minutes to about 30 minutes or more.

[0127] Aspect 41. The method according to any one of Aspects 37-47, wherein the substrate comprises polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), copolymers thereof, or blends thereof, including copolymers and blends with other polymers.

[0128] Aspect 42. The method according any one of Aspects 37-47, wherein the substrate is selected from the group consisting of PET bottles and containers, HDPE bottles and containers, glass bottles and containers, PVC sheets and bags, and LDPE sheets and bags.

[0129] Aspect 43. The method according to any one of Aspects 37-47, wherein the surface is a food-contacting surface.

[0130] Aspect 44. The method according to any one of Aspects 37-47, wherein the base coat layer has a substantially uniformly-textured outer surface.

[0131] Aspect 45. The method according to any one of Aspects 37-47, wherein the base coat layer has an outer surface that has nanoscale roughness and is substantially free of macro-scale roughness.

[0132] Aspect 46 The method according to any one of Aspects 37-47, wherein the base coat layer has an outer surface that is uniformly textured.

[0133] Aspect 47. The method according to any one of Aspects 37-47, further comprising applying an edible oil to the outer surface, wherein the edible oil spontaneously wets and adheres to the outer surface to form a slippery liquid over layer.

[0134] Aspect 48. A surface for food packaging made by a method according to any one of Aspects 37-47.

[0135] Aspect 49. An article of food packaging comprising a food-contacting surface having a structure according to any one of Aspects 1-20.

[0136] Aspect 50. An article of food packaging comprising a food-contacting surface made by a method according to any one of Aspects 37-47.

[0137] Aspect 51. The article of food packaging according to Aspect 49 or Aspect 50, wherein the food packaging is for a food product selected from the group consisting of ketchup, catsup, mustard, mayonnaise, syrup, honey, jelly, peanut butter, butter, chocolate syrup, shortening, butter, margarine, oleo, grease, dip, yogurt, and sour cream.