WO2021095043A1

WO2021095043A1 - Superhydrophobic coatings based on pickering emulsions

Info

Publication number: WO2021095043A1
Application number: PCT/IL2020/051191
Authority: WO
Inventors: Guy MECHREZ; Karthik Ananth Mani
Original assignee: The State Of Israel, Ministry Of Agriculture & Rural Development, Agricultural Research Organization (Aro) (Volcani Center)
Priority date: 2019-11-17
Filing date: 2020-11-17
Publication date: 2021-05-20
Also published as: IL293097A

Abstract

A particle comprising a core and a shell, wherein the shell comprises functionalized inorganic nanoparticles and the core comprises between 1% and 40% weight per weight (w/w) of a thermoplastic polymer is provided. Compositions and articles comprising particles according to the present invention are provided. Further, a method for coating a substrate, and a method for preparing the composition are provided.

Description

SUPERHYDROPHOBIC COATINGS BASED ON PICKERING EMULSIONS

CROSS REFERENCE TO RELATED APPLICATIONS [001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62/936,528 filed November 17, 2019 and U.S. Provisional Patent Application No. 62/953,452 filed December 24, 2019, both entitled

“SUPERHYDROPHOBIC COATING BASED ON PICKERING EMULSIONS”, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

[002] The present invention is in the field of Pickering emulsions.

BACKGROUND OF THE INVENTION

[003] In recent years, worldwide scientific communities and coating industries increased their attention towards development of superhydrophobic coatings with unique structure, properties and extended their applications in the field of anti-corrosion, self-cleaning, anti icing, anti-fogging, anti-fouling and other sectors. There are several methods available to produce superhydrophobic coatings. In contrast, there are few researches carried out to develop superhydrophobic coatings based on emulsion and Pickering emulsion.

[004] Pickering emulsions are typically known as emulsions of any type, for example oil-in-water or water-in-oil, stabilized by solid particles in place of surfactants. Pickering emulsions are stabilized by nanoparticles (NPs) that are self-assembled typically at the oil- water interface and acts as a physical barrier.

[005] There are several studies related to superhydrophobic coatings and surfaces however, the development of durable superhydrophobic surfaces is still a great challenge. The main parameter that defines the durability of a superhydrophobic surface is its abrasion resistance, i.e., the ability to maintain the property of superhydrophobicity upon introduction of abrasion on the coated surface. Therefore, there is still a great need to develop superhydrophobic surfaces, which will maintain their surface roughness and chemical nature after mechanical abrasion.

SUMMARY OF THE INVENTION

[006] According to one aspect, there is provided a particle comprising a core and a shell, wherein: a. the particle is characterized by an average diameter between 5 pm and 100 pm; b. the shell comprises functionalized inorganic nanoparticles and is characterized by a thickness between 5 nm and 100 nm; and c. the core comprises between 1% and 40% weight per weight (w/w) of a thermoplastic polymer.

[007] In some embodiments, the particle comprises between 1% and 10% (w/w) of the functionalized inorganic nanoparticles.

[008] In some embodiments, the ratio of the nanoparticles to the thermoplastic polymer is between 1:0.01 and 1:10 (w/w).

[009] In some embodiments, the shell comprises an outer layer of the thermoplastic polymer.

[010] In some embodiments, the functionalized is selected from halogen-functionalized, halocarbon-functionalized, silane-functionalized, alkyl-functionalized, alkoxy silane- functionalized, or any combination thereof.

[Oil] In some embodiments, the functionalized is perfluorooctyltriethoxysilane (FAS) functionalized, tricholoro(octadecyl) silane (OTS), or both.

[012] In some embodiments, the functionalized is perfluorooctyltriethoxysilane (FAS) functionalized and tricholoro(octadecyl)silane (OTS) at a ratio between 3:1 and 1:1 (w/w). [013] In some embodiments, the inorganic nanoparticles are selected from the group consisting of silica, aluminum oxide, iron oxide, zirconium oxide, titanium oxide, clay, and any combination thereof.

[014] In some embodiments, the core comprises at least two layers of the thermoplastic polymer.

[015] In some embodiments, the thermoplastic polymer comprises a polyacrylate, polysiloxane, polyethylene, polyisocyanate, polyurethane, fluorinated polymer, perfluorinated polymer, Teflon, Teflon PTFE, polyvinylchloride, polydimethylsiloxane, polystyrene, polytetrafluoroethylene, or any combination thereof.

[016] In some embodiments, the particle is characterized by a spherical shape, a quasi- spherical shape, a quasi-elliptical sphere, a deflated shape, a concave shape, an irregular shape, or any combination thereof.

[017] According to another aspect, there is provided a composition comprising the particle of the present invention, a first liquid and a second liquid, wherein the particle is in the interface of the first liquid and the second liquid.

[018] In some embodiments, the ratio of the first liquid and the second liquid is between 5:1 and 1:1 (w/w).

[019] In some embodiments, the composition is a dispersion or an emulsion. [020] In some embodiments, the first liquid comprises a mineral oil, hydrocarbon, fatty acid, mono-, di-, triacylglycerols, vegetable oil, wax, essential oil, aromatic oil, or any combination thereof.

[021] In some embodiments, the second liquid comprises methyl ethyl ketone (MEK), acetone, n-methyl-2-pyrrolidone (NMP), methylisobutylketone, dichloromethane, or any combination thereof.

[022] In some embodiments, the second liquid comprises the thermoplastic polymer.

[023] In some embodiments, the second liquid comprises acetone.

[024] In some embodiments, the composition is selected from the group consisting of an oil-in-oil (O/O) emulsion, acetone-in-oil (A/O) emulsion, oil-in-acetone (O/A) emulsion, oil-in-acetone-in-oil (O/A/O) emulsion, acetone-in- oil-acetone (A/O/A) emulsion, and any combination thereof.

[025] According to another aspect, there is provided an article comprising: a substrate in contact with a coating layer, wherein the coating layer comprises (i) a particle of the present invention or (ii) the composition of the present invention.

[026] In some embodiments, the coating comprises a plurality of dry particles bound to the substrate. In some embodiments, the dry particles are devoid of the first liquid and the second liquid. In some embodiments, the dry particles are characterized by concave porous structures.

[027] In some embodiments, the coating layer is characterized by an average thickness between 10 nm and 400 pm.

[028] In some embodiments, the coating layer is characterized by a water contact angle (WCA) in the range of 120° to 180°.

[029] In some embodiments, the coating layer is characterized by a roll-off (RA) angle of less than 10°.

[030] In some embodiments, the coating layer is stable at a temperature range of -100°C to 1500°C.

[031] In some embodiments, the coating layer is characterized by a transparency of 30% to 100%.

[032] According to another aspect, there is provided a method for forming the composition of the present invention, comprising: a. contacting 0.5% to 10% (w/w) of the functionalized inorganic nanoparticles with the first liquid, thereby forming a mixture; and b. contacting the mixture with the second liquid for a period of time. [033] In some embodiments, the contacting comprises high shear mixing, ultrasonication, overhead stirring, homogenizing, or a combination thereof.

[034] In some embodiments, the second liquid comprises 0.5% to 40% (w/w) of a thermoplastic polymer.

[035] In some embodiments, the ratio of the first liquid and the second liquid is 5:1 to 1:1 (w/w).

[036] According to another aspect, there is provided a method of manufacturing the article of the present invention, comprising: i) providing the composition of the present invention; ii) contacting the composition with a substrate, thereby obtaining a coating layer on the substrate; and iii) subjecting the layer to conditions suitable for drying, thereby obtaining the article.

[037] In some embodiments, the contacting comprises spin coating, roll coating, spray coating, kiss coating, air knife coating, anilox coater, flexo coater, gap coating, and dipping. [038] In some embodiments, the substrate is selected from the group comprising: a polymeric substrate, glass substrate, a metallic substrate, a paper substrate, a carton substrate, a tissue -based substrate, a brick wall, a sponge, a textile, or wood.

[039] In some embodiments, the conditions suitable for drying comprise exposing the layer to any one of air, heat, vacuum, thermal irradiation, microwave irradiation, infra-red irradiation, and UV-visible irradiation, or any combination thereof.

[040] In some embodiments, the coating layer has at least one characteristic selected from: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti adhesion coating, an anti-fouling coating, a drag reduction coating, an anti-corrosion coating, an anti-wetting coating, an oil-water separation coating, an anti-fogging coating, a chemical resistant coating, and an anti-abrasive coating.

[041] Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[042] Further embodiments and the full scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS [043] Figure 1 presents a schematic illustration of an O/O Pickering emulsion, according to an example of the present invention;

[044] Figure 2 presents a FT-IR spectra of bare and fluorinated silica nanoparticles (NPs) and schematic illustration of corresponding peaks to the functional groups;

[045] Figures 3A-3D present a schematic illustration of Cassie-Baxter wettability behavior of coated surface (Figure 3 A) smooth surface (Figure 3B), deflate seashell structure (Figure 3C) and deflate rugby ball structure (Figure 3D);

[046] Figures 4A-4F present confocal microscopy analysis of samples prepared as described herein: confocal microscopy images of 3% 1H,1H,2H,2H-

Perfluorooctyltriethoxysilane (FAS):Tricholoro(octadecyl)silane (OTS) (50:50) S1O2, mineral oil: acetone (1:1) (Figure 4A and Figure 4D), confocal microscopy images of 3% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4) (Figure 4B and Figure 4E), and confocal microscopy images of 4% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4) (Figure 4C and Figure 4F); all samples were prepared with 5% polymer;

[047] Figures 5A-5B present different magnitude SEM images of emulsions coated on polypropylene (PP) surfaces: emulsion of 3% FAS:OTS (50:50) S1O2, mineral oil: acetone (1:1) coated on PP surface (Figure 5A), and emulsion of 3% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4) coated on PP surface (Figure 5B); all samples were prepared with 5% polymer;

[048] Figure 6 presents SEM images, at different magnitudes, of the emulsions described herein (3% FAS:OTS (50:50) S1O2, mineral oil: acetone (1:1), 10% polymer incorporation) coated on PP surfaces;

[049] Figure 7 presents SEM images, at different magnitudes, of the emulsions described herein (3% FAS:OTS (50:50) S1O2, mineral oil: acetone (1:1), 30% polymer incorporation) emulsions coated on PP surfaces;

[050] Figures 8A-8C present wettability properties of the emulsions described herein when coating a PP surface: a) water contact angle (WCA) of 3% FAS:OTS 50:50) S1O2, mineral oil: acetone (1:1) emulsion (Figure 8A), WCA of 3% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4) emulsion (Figure 8B), and WCA of 4% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4) emulsion (Figure 8C); all samples were prepared with 5% polymer;

[051] Figures 9A-9B present wettability properties of the emulsions described herein when coating a PP surface: WCA of 3% FAS:OTS (50:50) S1O2, mineral oil: acetone (6:4), 10% polymer emulsion (Figure 9A) and WCA of 3% FAS:OTS (50:50) SiC , mineral oil: acetone (1:1), 30% polymer emulsion (Figure 9B);

[052] Figures 10A-10K present confocal microscopy images of emulsion formed using 3, 4, 5wt % of multi-functional silica, equal volume (1:1) fraction of mineral oil and acetone and different concentration of polymer: confocal images of emulsion silica dispersed in acetone initially (Figures 10A-C), confocal images of emulsion at 30wt% polymer concentration (silica dispersed in acetone initially (Figures 10D-F), confocal images of emulsion silica dispersed in oil initially (Figures 10G-I), particle concentration (P) dependence of the inverse of the mean diameter of the droplets (D) in emulsions formed at f oil or acetone = 0.5 and stabilised by multi-functional silica initially wetted by acetone or oil (Figure 10J); block line represents increase the droplet diameter while increasing particle concentration (particles disperse in acetone initially), circle represents decrease the droplet diameter while increase particle concentration (particles disperse in oil initially), triangle represents decrease the droplet diameter while increasing the particle concentration (particles disperse in acetone initially), and schematic and SEM images of emulsion formed using 4wt% of multi-functional silica, equal volume (1:1) fraction of mineral oil and acetone and 5, 10, 30wt% of polymer (Figure 10K); represents the changes of multiple emulsion to simple emulsion A/O, O/A/O (at 5wt%) to O/A, A/O/A (at 10wt%) to O/A (at 5wt%);

[053] Figures 11A-11I present confocal microscopy images of emulsion formed using multi-functional silica, different volume fraction of mineral oil and acetone, and different concentration of polymer (silica dispersed in acetone initially): confocal images of emulsion formed using 3, 4, 5wt% multi-functional silica at volume (6:4) fraction of mineral oil and acetone (Figures 11A-C), confocal images of emulsion formed using 3,4,5wt% multi-functional silica at volume (7:3) fraction of mineral oil and acetone (Figures 11D-F), confocal images of emulsion formed using 3wt% fully functionalized fluoro silica (100%), multi-functional silica (70:30 and 50:50) at equal volume fraction of mineral oil and acetone. Fully functionalized (100%) and multi-functionalized silica (70:30) formed oil-in-acetone emulsions and multi-functionalized silica (50:50) formed acetone-in-oil emulsions (Figures 11G-I); [054] Figures 12A-12I present microscopic images of emulsion formed using 3, 4, 5wt% of multi-functional silica, 1 : 1 and 6:4 fraction of mineral oil and acetone and different concentrations of polymer: confocal microscopy images of 10, 30wt% polymer concentration (Figures 12A-C), Cryo-SEM images of 5, 30wt% polymer concentration (Figures 12D-F) and SEM images of 5wt% polymer concentration (Figures 12G-I); the arrows indicates the anisotropic arrested coalescence structure;

[055] Figures 13A-13F present microscale and nanoscale structure in simple, multiple emulsion formed by 3, 4, 5wt% of multi-functional silica, equal volume (1:1) fraction of mineral oil and acetone and different concentration of polymer: 3wt% of multi-functional silica, 5wt% polymer based A/O emulsion (Figures 13A-B), 4wt% of multi-functional silica, 5wt% polymer based A/O, O/A/O double emulsion (Figures 13C-D), 5wt% of multi functional silica, 5wt% polymer based O/A, O/A/O double emulsion (Figure 13E) and 5wt% of multi-functional silica, 30wt% polymer based O/A emulsion (Figure 13F);

[056] Figure 14 presents a schematic illustration stabilization of multiple emulsion using multi-functional particles;

[057] Figures 15A-15R present different magnitude SEM images of emulsions coated on PP surfaces, emulsion formed using 3, 4, 5wt% of multi-functional silica, equal volume (Figures 15A-0) and 6:4 fraction (Figures 15P-R) of mineral oil and acetone and different concentrations of polymer: O/A, A/O/A emulsion based on 4wt% silica, 10wt% polymer, O/A emulsion based on 4wt% silica, 30wt% polymer (Figures 15A-C), O/A, A/O/A emulsion based on 5wt% silica (Figures 15D-F), 5wt% polymer (Figures 15G-I), O/A, A/O/A emulsion based on 5wt% silica and 10wt% polymer (Figures 15J-L), O/A emulsion based on 5wt% silica, 30wt% polymer (Figures 15M-0) and A/O, O/A/O emulsion based on 5wt% silica, 6:4 fraction of mineral oil and acetone and 5wt% polymer (Figures 15P-R); [058] Figure 16 presents a graph of the change in droplet diameter in optical microscopy and SEM: comparing the change in droplet average diameter of emulsion before (Optical microscopy) and after cured (SEM);

[059] Figures 17A-17C present microscopic images of arrested coalescence: SEM images of 4wt% and 5wt% of multi-functional silica, 1 : 1 fraction of mineral oil and acetone, 5wt% polymer concentration (Figures 17A-B) and SEM images of 5wt% of multi functional silica, 6:4 fraction of mineral oil and acetone, 5wt% polymer concentration (Figure 17C); the arrows indicates the anisotropic arrested coalescence structure;

[060] Figures 18A-18B present the interaction between the polymer and particles at the interface: schematic illustration of morphological changes of the droplets during acetone evaporation (Figure 18 A) and SEM images and Cryo-SEM images of different emulsion (Figure 18B);

[061] Figures 19A-19F present the wettability behavior of the coated samples according to the polymer concentration: WCA and RA of 3,4,5% multi-functional silica based mineral oil : acetone (1:1) system (Figures 19A-C) and WCA and roll-off angle (RA) of 3,4,5% multi-functional silica based mineral oil : acetone (6:4) system (Figures 19D-F); and [062] Figures 20A-20L present a schematic illustration of Cassie-Baxter wettability behavior of coated surface (Figure 20A), schematic illustration of sandpaper abrasion test (Figure 20B), self-cleaning behavior of coated PP surface after 50-time abrasion with sandpaper (Figures 20C-E), WCA of uncoated PP surfaces III (Figure 20F), WCA of 3, 5wt% of multi-functional silica, equal volume (1:1) fraction of mineral oil, acetone and 10, 30wt% of polymer based emulsion coated on PP surfaces (Figures 20G-H), WCA of after 4 time finger wipe of PP surfaces coated with emulsion (Figures 201- J), WCA of after 8 time finger wipe of PP surfaces coated with emulsion (Figures 20K-L).

DETAILED DESCRIPTION OF THE INVENTION [063] The present invention, in some embodiments thereof, is directed to a particle comprising a core and a shell, wherein the shell comprises functionalized inorganic nanoparticles, and the core comprises a thermoplastic polymer.

[064] In some embodiments, the present invention provides a composition comprising a particle as described herein, a first liquid and a second liquid, wherein the particle is in the interface of the first liquid and the second liquid.

[065] According to some embodiments, the present invention provides a composition comprising an emulsion comprising a plurality of particles. In some embodiments, the composition comprises an oil-in-oil (O/O) Pickering emulsion, or a double (O/O/O) Pickering emulsion.

[066] In some embodiments, the first liquid comprises an oil and the second liquid comprises acetone. In some embodiments, the composition is selected from the group consisting of a an oil-in-oil (O/O) emulsion, acetone-in-oil (A/O) emulsion, oil-in-acetone (O/A) emulsion, oil-in-acetone-in-oil (O/A/O) emulsion, acetone-in- oil-acetone (A/O/A) emulsion, and any combination thereof. In some embodiments, the type of emulsion obtained can be determined by choosing the amount of inorganic nanoparticles, the amount of polymer and the ratio between the first liquid and the second liquid. [067] The emulsions according to the present invention comprise particles comprising a shell of nanoparticles and a core encapsulating a polymer. In some embodiments, the emulsions are used as superhydrophobic coatings.

[068] According to some embodiments, the present invention provides a composition comprising an emulsion comprising a plurality of particles, the particles characterized by an average diameter between 5 pm and 100 pm, comprising a shell characterized by a thickness between 5 nm and 100 nm, and comprising functionalized inorganic nanoparticles. In some embodiments, the shell is a single layer shell. In some embodiments, the shell is a multi-layer shell. In some embodiments, the particles are in the interface of a first liquid (major phase) and a second liquid (minor phase), wherein the emulsion is stabilized by the nanoparticles. In some embodiments, the particles encapsulate a polymer. In some embodiments, the polymer is a thermoplastic polymer. In some embodiments, the particles are characterized by a core encapsulating 1% to 40% (w/w) of a thermoplastic polymer.

[069] The present invention, in some embodiments thereof, is directed to an article comprising a substrate in contact with a coating layer, wherein the coating layer comprises a particle described herein or a composition as described herein.

[070] According to some embodiments, the present invention provides an article comprising a substrate, and a plurality of particles comprising a core and a shell, wherein the plurality of particles are in the form of a coating layer on the substrate. In some embodiments, the particles encapsulate a thermoplastic polymer. In some embodiments, the particles are dried on the surface. In some embodiments, the coating comprising particles as described herein is characterized by a hierarchical structure comprising deflated particles.

[071] In some embodiments, the coating layer is a superhydrophobic coating. In some embodiments, the coating layer on the article, results from the emulsion described herein, after applied on a surface and dried. In some embodiments, the superhydrophobicity of the article is obtained by tuning the chemical nature of the particles, amount of polymer used and the shape of the coating layer. In some embodiments, the encapsulated thermoplastic polymer influences the hardness and shape of the coating layer. The structure and properties of the coating layer can be tuned by tuning the amount of polymer used in the emulsion. In some embodiments, the coating maintains its surface roughness and chemical nature after mechanical abrasion. The particle

[072] According to some embodiments, the present invention provides a particle comprising a core and a shell, wherein the particle is characterized by an average diameter between 5 pm and 100 pm. In some embodiments, the particle is characterized by a diameter between 1 pm and 100 pm, 5 pm and 100 pm, 10 pm and 100 pm, 50 pm and 100 pm, 1 pm and 80 pm, 10 pm and 80 pm, 50 pm and 80 pm, 1 pm and 10 pm, 5 pm and 10 pm, 1 pm and 50 pm, 10 pm and 50 pm, 5 pm and 50 pm, or between 1 pm and 5 pm, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[073] In some embodiments, the diameter of the particles described herein, represents an average diameter. In some embodiments, the size of the particles described herein represents an average or median size of a plurality of particles. In some embodiments, the average or the median size of at least e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% of the particles, ranges from: 5 pm to 50 pm, 1 pm to 50 pm, 5 pm to 10 pm, including any range therebetween. In some embodiments, a plurality of the particles has a uniform size. By "uniform" or "homogenous" it is meant to refer to size distribution that varies within a range of less than e.g., ±60%, ±50%, ±40%, ±30%, ±20%, or ±10%, including any value therebetween. Each possibility represents a separate embodiment of the invention.

[074] In some embodiments, the shell comprises functionalized inorganic nanoparticles and is characterized by a thickness between 5 nm and 100 nm, 15 nm and 100 nm, 30 nm and 100 nm, 5 nm and 50 nm, 15 nm and 50 nm, 30 nm and 50 nm, 1 nm and 50 nm, 2 nm and 50 pm, 5 pm and 10 pm, 10 nm and 50 nm, 5 nm and 30 nm, 15 nm and 30 nm, 1 nm and 20 pm, 2 nm and 20 nm, 5 nm and 20 nm, or between 10 nm and 20 nm, including any range therebetween. Each possibility represents a separate embodiment of the invention. In some embodiments, the shell thickness is quantified using scanning electron microscopy. [075] In some embodiments, the particle comprises between 0.01% and 10% (w/w), 0.05% and 10% (w/w), 0.09% and 10% (w/w), 0.1% and 10% (w/w), 0.5% and 10% (w/w), 0.9% and 10% (w/w), 1% and 10% (w/w), 5% and 10% (w/w), 0.01% and 9% (w/w), 0.05% and 9% (w/w), 0.09% and 9% (w/w), 0.1% and 9% (w/w), 0.5% and 9% (w/w), 0.9% and 9% (w/w), 1% and 9% (w/w), 5% and 9% (w/w), 0.01% and 5% (w/w), 0.05% and 5% (w/w), 0.09% and 5% (w/w), 0.1% and 5% (w/w), 0.5% and 5% (w/w), 0.9% and 5% (w/w), or between 1% and 5% (w/w), of the functionalized inorganic nanoparticles, including any range therebetween. Each possibility represents a separate embodiment of the invention. [076] In some embodiments, the shell is a multi-layer shell. In some embodiments, the shell comprises at least two layers. In some embodiments, the shell comprises an inner layer and an outer layer. In some embodiments, the inner layer is facing the core of the particle. In some embodiments, the outer layer is facing the exterior of the particle. In some embodiments, the shell comprises an inner layer of the functionalized inorganic nanoparticles and an outer layer of thermoplastic polymer, wherein the inner layer is positioned between the core and the outer layer.

[077] In some embodiments, functionalized is selected from halogen-functionalized, halocarbon-functionalized, alkyl-functionalized, silane-functionalized, alkoxy silane- functionalized, alkyl silane-functionalized, or any combination thereof.

[078] In some embodiments, functionalized is perfluorooctyltriethoxy silane (FAS) functionalized, tricholoro(octadecyl) silane (OTS), or both.

[079] In some embodiments, functionalized is perfluorooctyltriethoxysilane (FAS) functionalized and tricholoro(octadecyl)silane (OTS) at a ratio between 3:1 and 1:1 (w/w), 2.5:1 and 1:1 (w/w), 2:1 and 1:1 (w/w), 1.5:1 and 1:1 (w/w), or 1.1:1 and 1:1 (w/w), including any range therebetween. Each possibility represents a separate embodiment of the invention.

[080] In some embodiments, functionalized is perfluorooctyltriethoxysilane (FAS) functionalized and tricholoro(octadecyl) silane (OTS) at a ratio of 1:1 (w/w).

[081] In some embodiments, the core comprises at least two layers of the thermoplastic polymer. In some embodiments, the core comprises alternating layers of thermoplastic polymer and inorganic nanoparticles.

[082] In some embodiments, the core encapsulates a particle as described hereinabove. In some embodiments, the core encapsulates a particle comprising a shell functionalized inorganic nanoparticles, wherein the shell encapsulates between 1% and 40% (w/w) of a thermoplastic polymer.

[083] In some embodiments, the inorganic nanoparticles are selected from the group consisting of silica, aluminum oxide, iron oxide, zirconium oxide, titanium oxide, clay, and any combination thereof.

[084] In some embodiments, the functionalized inorganic nanoparticles are selected from fluoro-functionalized silica nanoparticles, chloro -functionalized silica nanoparticles, fluorocarbon-functionalized silica nanoparticles, silane-functionalized silica nanoparticles, or any combination thereof. [085] The term “silica” as used here refers to a structure containing at least the following the elements: silicon and oxygen. Silica may have the fundamental formula of SiC or it may have another structure including Si_xO_y (where x and y can each independently be about 1 to 10). Additional elements including, but not limited to, carbon, nitrogen, sulfur, phosphorus, or ruthenium may also be used. Silica may be a solid particle or it may have pores.

[086] In some embodiments, the nanoparticle characterized by a median particle size of 1 nm to 900 nm. In some embodiments, the nanoparticle is characterized by a median particle size of 2 nm to 600 nm, 2 nm to 550 nm, 2 nm to 520 nm, 2 nm to 500 nm, 2 nm to 480 nm, 2 nm to 450 nm, 2 nm to 400 nm, 2 nm to 350 nm, 2 nm to 300 nm, 2 nm to 250 nm, 2 nm to 200 nm, 2 nm to 150 nm, 2 nm to 100 nm, 5 nm to 600 nm, 10 nm to 600 nm, 15 nm to 600 nm, 20 nm to 600 nm, 40 nm to 600 nm, 50 nm to 600 nm, 100 nm to 600 nm, 5 nm to 500 nm, 10 nm to 500 nm, 15 nm to 500 nm, 20 nm to 500 nm, 40 nm to 600 nm, 50 nm to 500 nm, 100 nm to 500 nm, 5 nm to 400 nm, 10 nm to 400 nm, 15 nm to 400 nm, 20 nm to 400 nm, 40 nm to 400 nm, 50 nm to 400 nm, 100 nm to 400 nm, 5 nm to 50 nm, 5 nm to 40 nm, 2 nm to 50 nm, or 2 nm to 40 nm, including any range therebetween. Each possibility represents a separate embodiment of the invention. In some embodiments, the size of at least 90% of the nanoparticles varies within a range of less than ±25%, ±20%, ±15%, ±19%, ±5%, including any value therebetween. Each possibility represents a separate embodiment of the invention.

[087] Herein throughout, the terms “nanoparticle”, “nano”, “nanosized”, and any grammatical derivative thereof, which are used herein interchangeably, describe a particle featuring a size of at least one dimension thereof (e.g., diameter, length) that ranges from about 1 nanometer to 100 nanometers. Herein throughout, "NP(s)" designates nanoparticle(s).

[088] As used herein the terms "average" or "median" size refer to diameter of the particles. The term "diameter" is art-recognized and is used herein to refer to either of the physical diameter (also termed “dry diameter”) or the hydrodynamic diameter. As used herein, the "hydrodynamic diameter" refers to a size determination for the composition in solution (e.g., aqueous solution) using any technique known in the art, e.g., dynamic light scattering (DLS). In some embodiments, the dry diameter of the particles, as prepared according to some embodiments of the invention, may be evaluated using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) imaging. [089] The particle(s) can be generally shaped as a sphere, incomplete-sphere, particularly the size attached to the substrate, a rod, a cylinder, a ribbon, a sponge, and any other shape, or can be in a form of a cluster of any of these shapes, or can comprise a mixture of one or more shapes.

[090] In some embodiments, the core comprises between 1 % and 40% weight per weight (w/w) of a thermoplastic polymer. In some embodiments, the core comprises between 5% and 40% (w/w), 10% and 40% (w/w), 25% and 40% (w/w), 1% and 30% (w/w), 5% and 30% (w/w), 10% and 30% (w/w), 25% and 30% (w/w), 1% and 10% (w/w), 5% and 10% (w/w), or 1% and 5% (w/w), of a thermoplastic polymer, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[091] In some embodiments, the ratio of the nanoparticles to the polymer is between 1:0.01 and 1:10 (w/w), 1:0.05 and 1:10 (w/w), 1:0.09 and 1:10 (w/w), 1:0.1 and 1:10 (w/w), 1:0.5 and 1:10 (w/w), 1:0.9 and 1:10 (w/w), 1:1 and 1:10 (w/w), 1:2 and 1:10 (w/w), 1:5 and 1:10 (w/w), 1:7 and 1:10 (w/w), 1:0.01 and 1:5 (w/w), 1:0.05 and 1:5 (w/w), 1:0.09 and 1:5 (w/w), 1:0.1 and 1:5 (w/w), 1:0.5 and 1:5 (w/w), 1:0.9 and 1:5 (w/w), 1:1 and 1:5 (w/w), or betweenl:2 and 1:5 (w/w), including any range therebetween. Each possibility represents a separate embodiment of the invention.

[092] As used herein, the term “thermoplastic” refers to a class of polymers that can be softened and melted by the application of heat, and can be processed either in the heat- softened state (e.g. by thermoforming) or in the liquid state (e.g. by extrusion and injection molding). Thermoplastic polymers solidify upon cooling, maintaining their shape.

[093] As used herein throughout, the term “polymer” describes an organic substance composed of a plurality of repeating structural units (backbone units) covalently connected to one another. In some embodiments, the thermoplastic polymer comprises a poly acrylate, polysiloxane, polyethylene, polyisocyanate, polyurethane, fluorinated polymer, perfluorinated polymer, Teflon, Teflon PTFE, polyvinylchloride, polydimethylsiloxane, polystyrene, polytetrafluoroethylene, or any combination thereof.

[094] In some embodiments, the core of the particles is void. In some embodiments, the core of the particles is devoid of a polymer.

[095] In some embodiments, the particle is characterized by a spherical shape, a quasi- spherical shape, a quasi-elliptical sphere, a deflated shape, a concave shape, an irregular shape, or any combination thereof. The composition

[096] According to some embodiments, the present invention provides a composition comprising a particle described hereinabove, a first liquid and a second liquid, wherein the particle is in the interface of the first liquid and the second liquid.

[097] In some embodiments the composition is selected from the group consisting of a dispersion, an emulsion, an oil-in-oil (O/O) emulsion, acetone-in-oil (A/O) emulsion, oil- in-acetone (O/A) emulsion, oil-in-acetone-in-oil (O/A/O) emulsion, acetone-in- oil-acetone (A/O/A) emulsion, and any combination thereof.

[098] In some embodiments, when mixed, a first liquid forms a first phase and a second liquid forms a second phase. In some embodiments, a first liquid is in a major phase and a second liquid is in a minor phase. In some embodiments, a major phase is a continuous phase. In some embodiments, a minor phase is a dispersed phase.

[099] In some embodiments, a composition as described herein is an emulsion. In some embodiments, the emulsion is characterized by a phase inversion.

[0100] In some embodiments, the increase of viscosity of a liquid of a phase, leads to a shift of the phases. In some embodiments, increase of viscosity of a liquid of a phase, leads to a shift of a dispersed phase to a continuous phase. In some embodiments, the increasing viscosity of a phase induces inorganic particle aggregates to change their hydrophobicity behavior resulting in phase inversion.

[0101] In some embodiments, the first liquid comprises a mineral oil, hydrocarbon, fatty acid, mono-, di-, triacylglycerols, vegetable oil, wax, essential oil, aromatic oil, or any combination thereof.

[0102] In some embodiments, the second liquid comprises methyl ethyl ketone (MEK), acetone, n-methyl-2-pyrrolidone (NMP), methylisobutylketone, dichloromethane, or any combination thereof. In some embodiments, the second liquid comprises the thermoplastic polymer. In some embodiments, the second liquid comprises acetone. In some embodiments, the second liquid comprises acetone and the thermoplastic polymer.

[0103] In some embodiments, the composition is selected from the group consisting of an oil-in-oil (O/O) emulsion, acetone-in-oil (A/O) emulsion, oil-in-acetone (O/A) emulsion, oil-in-acetone-in-oil (O/A/O) emulsion, acetone-in- oil-acetone (A/O/A) emulsion, and any combination thereof.

[0104] In some embodiments, the viscosity of a phase increases with the increasing of the amount of polymer. In some embodiments, increasing the polymer concentration leads to a phase inversion. [0105] In some embodiments, the major phase comprises mineral oil, hydrocarbon, fatty acid, mono-, di-, triacylglycerols, vegetable oil, wax, essential oil, aromatic oil, or any combination thereof.

[0106] In some embodiments, the minor phase comprises a solvent insoluble in water. In some embodiments, the minor phase comprises a non-polar organic solvent. In some embodiments, the minor phase comprises methyl ethyl ketone (MEK), acetone, n-methyl- 2-pyrrolidone (NMP), methylisobutylketone, dichloromethane, or any combination thereof. In some embodiments, the major phase comprises a thermoplastic polymer.

[0107] In some embodiments, the major phase is an oil phase. In some embodiments, the minor phase is an oil phase.

[0108] As used herein, the term “oil” refers to any suitable water-immiscible compound. In some embodiments, the oil is an oil that is liquid at room temperature (20° C; 1013 mbar). In embodiments, the oil is selected from the group consisting of essential oils, vegetable oils, mineral oils, organic oils, lipids, and any water-immiscible liquids.

[0109] As used herein, the term “mineral oil” refers to an oil obtained from a mineral source. In some embodiments, mineral oil refers to a liquid by-product of refining crude oil to make gasoline and other petroleum products. A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the range of C-15 to C-40. Mineral oil is available in light and heavy grades. In some embodiments mineral oil refers to a raw and/or purified distillate fraction obtained from a mineral source. In some embodiments, the mineral oil is chemically modified. Mineral oils are well known in the art and are used herein in the same manner as they are commonly used in the art. Such oils are readily available from commercial chemicals suppliers throughout the world. Methods for preparation of mineral oils are well known in the art and it would be will be apparent to those skilled in the art. [0110] Non-limiting examples of a suitable oil according to the present invention include mineral oil, paraffinic oil (based on n-alkanes), naphthenic oil (based on cycloalkanes), hydrocarbon oil (based on hydrocarbons), vegetable oil (oil extracted from seeds, or other parts of fruits), wax, essential oil (based on extracts from plants), and aromatic oil (based on aromatic hydrocarbons and distinct from essential oils). Such oils are well known in the art and it would be will be apparent to those skilled in the art.

[0111] In some embodiments, the ratio of the major phase and the minor phase is 5:1 to 1:1 (w/w), 4:1 to 1:1 (w/w), 3:1 to 1:1 (w/w), or 2:1 to 1:1 (w/w), including any range therebetween. In some embodiments, the ratio of the major phase and the minor phase is 1:1 (w/w). Each possibility represents a separate embodiment of the invention. [0112] In some embodiments, the composition comprises an emulsion, comprising a plurality of particles. In some embodiments, the particles are in the form of droplets.

[0113] In some embodiments, the droplets encapsulate one or more particles as described hereinabove. In some embodiments, the droplet is characterized by an average diameter between 5 pm and 100 pm and comprises a core and a shell, wherein the shell comprises functionalized inorganic nanoparticles as described herein above and the core encapsulates i) a thermoplastic polymer and ii) a particle comprising a core and a shell, wherein a) the particle is characterized by an average diameter between 5 pm and 100 pm; b) the shell comprises functionalized inorganic nanoparticles and is characterized by a thickness between 5 nm and 100 nm; and c) the core comprises between 1% and 40% weight per weight (w/w) of a thermoplastic polymer. In some embodiments, the core further encapsulates a liquid. In some embodiments, the core further encapsulates acetone.

[0114] As used herein, the term “Pickering emulsion” refers to an emulsion that utilizes solid particles as a stabilizer to stabilize droplets of a substance, in a dispersed phase in the form of droplets dispersed throughout a continuous phase.

[0115] As used herein, the term “emulsion” refers to a combination of at least two fluids, where one of the fluids is present in the form of droplets in the other fluid. The term “emulsion” includes microemulsions.

[0116] As used herein, the term “fluid” refers to a substance that tends to flow and to conform to the outline of its container, i.e., a liquid, a gas, a viscoelastic fluid, etc. Typically, fluids are materials that are unable to withstand a static shear stress, and when a shear stress is applied, the fluid experiences a continuing and permanent distortion. The fluid may have any suitable viscosity that permits flow. If two or more fluids are present, each fluid may be independently selected among essentially any fluids (liquids, gases, and the like) by those of ordinary skill in the art, by considering the relationship between the fluids. In some cases, the droplets may be contained within a carrier fluid, e.g., a liquid.

[0117] In some embodiments, the droplets have a diameter of 1 pm to 100 pm, 5 pm to 100 pm, 10 pm to 100 pm, 50 pm to 100 pm, 1 pm to 80 pm, 10 pm to 80 pm, 50 pm to 80 pm, 1 pm to 10 pm, 5 pm to 10 pm, 1 pm to 50 pm, 10 pm to 50 pm, 5 pm to 50 pm, or 1 pm to 5 pm, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0118] As used herein, the term “droplet” refers to an isolated portion of a first fluid that is surrounded by a second fluid. It is to be noted that a droplet is not necessarily spherical; but may assume other shapes as well, for example, depending on the external environment. In some embodiments, the droplet has a minimum cross-sectional dimension that is substantially equal to the largest dimension of the channel perpendicular to fluid flow in which the droplet is located. In some cases, the droplet may be a vesicle, such as a liposome, a colloidosome, or a polymersome. The fluidic droplets may have any shape and/or size. Typically, monodisperse droplets are of substantially the same size. The shape and/or size of the fluidic droplets can be determined, for example, by measuring the average diameter or other characteristic dimension of the droplets. The “average diameter” of a plurality or series of droplets is the arithmetic average of the average diameters of each of the droplets. Those of ordinary skill in the art will be able to determine the average diameter (or other characteristic dimension) of a plurality or series of droplets, for example, using laser light scattering, microscopic examination, or other known techniques. The average diameter of a single droplet, in a non-spherical droplet, is the diameter of a perfect sphere having the same volume as the non-spherical droplet. In some embodiments, the average diameter of a droplet (and/or of a plurality or series of droplets) is, 5 pm to 100 pm, 5 pm to 50 pm, 1 pm to 50 pm, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0119] In some embodiments, the composition comprises an emulsion, comprising a plurality of particles, having a diameter of 5 pm to 100 pm, the particles comprising a shell having a thickness of 5 nm to 100 nm, and comprising inorganic nanoparticles. In some embodiments, the shell has a thickness in the range of 5 nm to 50 nm, 15 nm to 50 nm, 30 nm to 50 nm, 1 nm to 50 nm, 2 nm to 50 pm, 5 pm to 10 pm, 10 nm to 50 nm, 5 nm to 30 nm, 15 nm to 30 nm, 1 nm to 20 pm, 2 nm to 20 nm, 5 nm to 20 nm, or 10 nm to 20 nm, including any range therebetween. Each possibility represents a separate embodiment of the invention. In some embodiments, the shell thickness is quantified using scanning electron microscopy.

[0120] In some embodiments, the particles are in the interface of a first liquid and a second liquid, and the emulsion is stabilized by the inorganic nanoparticles. In some embodiments, the particles are in the interface of a first phase and a second phase, and the emulsion is stabilized by the inorganic nanoparticles. In some embodiments, the particles are in the interface of a major phase and a minor phase, and the emulsion is stabilized by the inorganic nanoparticles.

[0121] In some embodiments, the composition comprises 0.01% to 10% (w/w), 0.05% to 10% (w/w), 0.09% to 10% (w/w), 0.1% to 10% (w/w), 0.5% to 10% (w/w), 0.9% to 10% (w/w), 1% to 10% (w/w), 5% to 10% (w/w), 0.01% to 9% (w/w), 0.05% to 9% (w/w), 0.09% to 9% (w/w), 0.1% to 9% (w/w), 0.5% to 9% (w/w), 0.9% to 9% (w/w), 1% to 9% (w/w), 5% to 9% (w/w), 0.01% to 5% (w/w), 0.05% to 5% (w/w), 0.09% to 5% (w/w), 0.1% to 5% (w/w), 0.5% to 5% (w/w), 0.9% to 5% (w/w), or 1% to 5% (w/w), of the particles, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0122] In some embodiments, the composition comprises 0.01% to 10% (w/w), 0.05% to 10% (w/w), 0.09% to 10% (w/w), 0.1% to 10% (w/w), 0.5% to 10% (w/w), 0.9% to 10% (w/w), 1% to 10% (w/w), 5% to 10% (w/w), 0.01% to 9% (w/w), 0.05% to 9% (w/w), 0.09% to 9% (w/w), 0.1% to 9% (w/w), 0.5% to 9% (w/w), 0.9% to 9% (w/w), 1% to 9% (w/w), 5% to 9% (w/w), 0.01% to 5% (w/w), 0.05% to 5% (w/w), 0.09% to 5% (w/w), 0.1% to 5% (w/w), 0.5% to 5% (w/w), 0.9% to 5% (w/w), or 1% to 5% (w/w), of the functionalized inorganic nanoparticles, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0123] In some embodiments, the major phase comprises a thermoplastic polymer. In some embodiments, the emulsion comprises a thermoplastic polymer dissolved in the major phase. In some embodiments, the minor phase comprises a thermoplastic polymer. In some embodiments, the emulsion comprises a thermoplastic polymer dissolved in the minor phase. In some embodiments, the core of the particles encapsulate a thermoplastic polymer. [0124] In some embodiments, the core of the particles encapsulates 1% to 40% (w/w) of a thermoplastic polymer. In some embodiments, the composition comprises 5% to 40% (w/w), 10% to 40% (w/w), 25% to 40% (w/w), 1% to 30% (w/w), 5% to 30% (w/w), 10% to 30% (w/w), 25% to 30% (w/w), 1% to 10% (w/w), 5% to 10% (w/w), or 1% to 5% (w/w), of a thermoplastic polymer, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0125] In some embodiments, the ratio of the nanoparticles to the thermoplastic polymer is 1:0.01 to 1:10 (w/w), 1:0.05 to 1:10 (w/w), 1:0.09 to 1:10 (w/w), 1:0.1 to 1:10 (w/w), 1:0.5 to 1:10 (w/w), 1:0.9 to 1:10 (w/w), 1:1 to 1:10 (w/w), 1:2 to 1:10 (w/w), 1:5 to 1:10 (w/w), 1:7 to 1:10 (w/w), 1:0.01 to 1:5 (w/w), 1:0.05 to 1:5 (w/w), 1:0.09 to 1:5 (w/w), 1:0.1 to 1:5 (w/w), 1:0.5 to 1:5 (w/w), 1:0.9 to 1:5 (w/w), 1:1 to 1:5 (w/w), or 1:2 to 1:5 (w/w), including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0126] In some embodiments, the composition comprises 1% to 6% (w/w) of the inorganic nanoparticles. In some embodiments, the composition comprises 3 % (w/w) of the inorganic nanoparticles. In some embodiments, a composition comprising 3 % (w/w) of the inorganic nanoparticles and different polymer concentrations, is an A/O composition or O/A composition. In some embodiments, the particles are characterized by a spherical and non-spherical structure. In some embodiments, the obtained structure is due to the weak interaction between silica and polymer at the interface.

[0127] In some embodiments, a composition comprising 5% (w/w) of the inorganic nanoparticles is an A/O/A emulsion. In some embodiments, the particles are characterized by a deflated structure.

[0128] In some embodiments, the shell comprises an inner layer of the functionalized inorganic nanoparticles and an outer layer of thermoplastic polymer, wherein the inner layer is positioned between the core and the outer layer. In some embodiments, the outer layer is in fluid communication with the first phase and the second phase.

[0129] In some embodiments, the composition is for use as: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti-adhesion coating, an anti-fouling coating, a drag reduction coating, an anti-corrosion coating, an anti- wetting coating, an oil- water separation coating, an anti-fogging coating, a chemical resistant coating, or an anti abrasive coating.

The article

[0130] According to some embodiments, the present invention provides an article comprising a substrate in contact with a coating layer, wherein the coating layer comprises (i) a particle described hereinabove or (ii) the composition described hereinabove.

[0131] According to some embodiments, the present invention provides an article comprising(i) a substrate, and (ii) a plurality of particles comprising a core and a shell and having a deflated structure, wherein the plurality of particles are in the form of a coating layer on the substrate.

[0132] In some embodiments, the oil is adsorbed on the surface of the particles. In some embodiments, the shell comprises functionalized inorganic nanoparticles and having a thickness in the range of 5 nm to 100 nm. In some embodiments, the core encapsulates a thermoplastic polymer.

[0133] According to some embodiments, the present invention provides an article comprising the composition of the present invention. In some embodiments, the article comprises the composition and a substrate, wherein the composition is in the form of a coating layer on the substrate. In some embodiments, the composition is in the form of a coating layer in at least a portion of a surface of the substrate. [0134] According to some embodiments, the present invention provides an article comprising the emulsion present invention. In some embodiments, the article comprises the emulsion and a substrate, wherein the emulsion is in the form of a coating layer on the substrate. In some embodiments, the emulsion is in the form of a coating layer in at least a portion of a surface of the substrate. In some embodiments, the emulsion is evaporated resulting in a plurality of particles comprising a core and a shell and having a deflated structure, wherein the plurality of particles are in the form of a coating layer on the substrate. In some embodiments, the particles encapsulate a thermoplastic polymer. In some embodiments, the amount of encapsulated polymer is defined in the emulsion. In some embodiments, the encapsulated polymer is 1% to 40% (w/w), 5% to 40% (w/w), 10% to 40% (w/w), 25% to 40% (w/w), 1% to 30% (w/w), 5% to 30% (w/w), 10% to 30% (w/w), 25% to 30% (w/w), 1% to 10% (w/w), 5% to 10% (w/w), or 1% to 5% (w/w), including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0135] In some embodiments, the evaporation of the emulsion results in droplet deflation. In some embodiments, the evaporation of the acetone from the emulsion results in droplet deflation. In some embodiments, the emulsion is evaporated resulting in a hierarchical coating structure comprising deflated droplets. In some embodiments, the structure comprises nano and micron scale hierarchical porous/structures. In some embodiments, the structure comprises nano and micron scale hierarchical deflated particles. In some embodiments, the particles are concave. In some embodiments, the concave particles are characterized by different morphologies. In some embodiments, the inorganic nanoparticles are adsorbed in the concave particles.

[0136] In some embodiments, the dry particles are characterized by concave porous structures. In some embodiments, the concave porous structures are micronized, nanosized, or both. In some embodiments, the concave porous structures are characterized by a median size ranging from 300 pm to 5 nm, 200 pm to 5 nm, 100 pm to 5 nm, 50 pm to 5 nm, 30 pm to 5 nm, 10 pm to 5 nm, 5 pm to 5 nm, 1 pm to 5 nm, 300 pm to 10 nm, 200 pm to 10 nm, 100 pm to 10 nm, 50 pm to 10 nm, 30 pm to 10 nm, 10 pm to 10 nm, 5 pm to 10 nm, 1 pm to 10 nm, 300 pm to 50 nm, 200 pm to 50 nm, 100 pm to 50 nm, 50 pm to 50 nm, 30 pm to 50 nm, 10 pm to 50 nm, 5 pm to 50 nm, 1 pm to 50 nm, 300 pm to 100 nm, 200 pm to 100 nm, 100 pm to 100 nm, 50 pm to 100 nm, 30 pm to 100 nm, 10 pm to 100 nm, 5 pm to 100 nm, or 1 pm to 100 nm, including any range therebetween. Each possibility represents a separate embodiment of the invention. [0137] In some embodiments, an article comprising a substrate, and an evaporated emulsion as described hereinabove in the form of a coating layer on the substrate is characterized by an improved superhydrophobicity. In some embodiments, the improvement in the superhydrophobicity is due to the deflated particles of coating material. [0138] As used herein, the terms “hierarchically porous” and “hierarchical porosity” refer to the presence of at least two different pore sizes/deflated particle sizes in the coating. The different pores/deflated particles may be arranged, with respect to each other, in any of several different ways. In other embodiments, at least one (or both, or all) of the mesopores pores/deflated particles are arranged in an ordered (i.e., patterned) manner.

[0139] In some embodiments, the substrate is selected from, a polymeric substrate, glass substrate, a metallic substrate, a paper substrate, a carton substrate, a tissue-based substrate, a brick wall, a sponge, a textile, or wood.

[0140] In some embodiments, the inorganic nanoparticles are selected from the group consisting of silica, titanium oxide, clay, and any combination thereof.

[0141] In some embodiments, functionalized is selected from fluoro-functionalized nanoparticles, silane-functionalized nanoparticles, or both.

[0142] Non-limiting examples of silane-functionalized nanoparticles include silane, methyl silane, linear alkyl silane, branched alkyl silane, aromatic silane, fluorinated alkyl silane, and dialkyl silane.

[0143] In some embodiments, the thermoplastic polymer comprises a polyacrylate, polysiloxane, polyethylene, polyisocyanate, polyurethane, fluorinated polymer, perfluorinated polymer, Teflon, Teflon PTFE, polyvinylchloride, polydimethylsiloxane, polystyrene, polytetrafluoroethylene, or any combination thereof.

[0144] In some embodiments, the oil comprises mineral oil, hydrocarbon, fatty acid, mono-, di-, triacylglycerols, vegetable oil, wax, essential oil, aromatic oil, or any combination thereof.

[0145] In some embodiments, the coating layer is characterized by an average thickness of 10 nm to 400 pm, 25 nm to 400 pm, 50 nm to 400 pm, 100 nm to 400 pm, 250 nm to 400 pm, 500 nm to 400 pm, 900 nm to 400 pm, 1 pm to 400 pm, 10 pm to 400 pm, 50 pm to 400 pm, 100 pm to 400 pm, 250 pm to 400 pm, 10 nm to 100 pm, 25 nm to 100 pm, 50 nm to 100 pm, 100 nm to 100 pm, 250 nm to 100 pm, 500 nm to 100 pm, 900 nm to 100 pm, 1 pm to 100 pm, 10 pm to 100 pm, 50 pm to 100 pm, 10 nm to 10 pm, 25 nm to 10 pm, 50 nm to 10 pm, 100 nm to 10 pm, 250 nm to 10 pm, 500 nm to 10 pm, 900 nm to 10 mih, or 1 mih to 10 mih, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0146] In some embodiments, the coating layer is characterized by a water contact angle (WCA) in the range of 120° to 180°, 130° to 180°, 120° to 168°, 130° to 165°, 130° to 160°, 130° to 150°, or 135° to 165°, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0147] In some embodiments, the article is characterized by a water contact angle of at least 120 °. In some embodiments, the article is characterized by a water contact angle in the range of 100° to 180°, 110° to 180°, 120° to 180°, 130° to 180°, 130° to 168°, 130° to 165°, 130° to 160°, 130° to 150°, or 135° to 165°, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0148] In some embodiments, the article is characterized by a surface contact angle of more than 100°. In some embodiments, the coating layer is characterized by a surface contact angle of more than 105°, 110°, 115°, 120°, 125°, 130°, including any value therebetween. Each possibility represents a separate embodiment of the invention.

[0149] In some embodiments, the coating layer is characterized by a roll-off angle (RA) of less than 10°, less than 9°, less than 8°, less than 7°, less than 6°, or less than 5°, including any value therebetween. In some embodiments, the coating layer is characterized by a RA angle of 10° to 1°, 10° to 3°, 10° to 5°, 9° to 1°, 9° to 3°, 9° to 5°, 8° to 1°, 8° to 3°, or 8° to 5°, including any range therebetween. In some embodiments, the article is characterized by a RA angle of less than 10°, less than 9°, less than 8°, less than 7°, less than 6°, or less than 5°, including any value therebetween. In some embodiments, the article is characterized by a RA angle of 10° to 1°, 10° to 3°, 10° to 5°, 9° to 1°, 9° to 3°, 9° to 5°, 8° to 1°, 8° to 3°, or 8° to 5°, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0150] In some embodiments, the coating layer is stable at a temperature range of -100°C to 1500°C, -50°C to 1500°C, -10°C to 1500°C, 0°C to 1500°C, 10°C to 1500°C, 50°C to 1500°C, 100°C to 1500°C, 500°C to 1500°C, -100°C to 500°C, -50°C to 500°C, -10°C to 500°C, 0°C to 500°C, 10°C to 500°C, 50°C to 500°C, or 100°C to 500°C, including any range therebetween. Each possibility represents a separate embodiment of the invention. [0151] In some embodiments, the coating layer is characterized by a transparency of 30% to 100%, 40% to 100%, 50% to 100%, 60% to 100%, 70% to 100%, 80% to 100%, 30% to 99.9%, 40% to 99.9%, 50% to 99.9%, 60% to 99.9%, 70% to 99.9%, 80% to 99.9%, 30% to 99%, 40% to 99%, 50% to 99%, 60% to 99%, 70% to 99%, 80% to 99%, 30% to 98%, 40% to 98%, 50% to 98%, 60% to 98%, 70% to 98%, 80% to 98%, 30% to 95%, 40% to 95%, 50% to 95%, 60% to 95%, 70% to 95%, 80% to 95%, 30% to 90%, 40% to 90%, 50% to 90%, 60% to 90%, 70% to 90%, or 80% to 90%, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0152] In some embodiments, the article is characterized by a transparency of 30% to 100%, 40% to 100%, 50% to 100%, 60% to 100%, 70% to 100%, 80% to 100%, 30% to 99.9%, 40% to 99.9%, 50% to 99.9%, 60% to 99.9%, 70% to 99.9%, 80% to 99.9%, 30% to 99%, 40% to 99%, 50% to 99%, 60% to 99%, 70% to 99%, 80% to 99%, 30% to 98%, 40% to 98%, 50% to 98%, 60% to 98%, 70% to 98%, 80% to 98%, 30% to 95%, 40% to 95%, 50% to 95%, 60% to 95%, 70% to 95%, 80% to 95%, 30% to 90%, 40% to 90%, 50% to 90%, 60% to 90%, 70% to 90%, or 80% to 90%, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0153] In some embodiments, the coating layer is characterized by a pattern comprising microstmctures and nanostructures.

[0154] In some embodiments, the microstructures have a spherical shape, a quasi- spherical shape, a quasi-elliptical sphere, an irregular shape, or any combination thereof. [0155] In some embodiments, the plurality of particles comprising a core and a shell, form microstmctures having a deflated structure. Reference is made to Figures 3A-D, exemplifying the deflated structures.

[0156] In some embodiments, the diameter of the microstmctures can be compared to the diameter of the corresponding particles of the emulsion described herein. In some embodiments, the diameter of the deflated particles is 0.1% to 10%, 0.2% to 10%, 0.3% to 10%, 0.4% to 10%, 0.5% to 10%, 0.1% to 8%, 0.1% to 5%, or 0.1% to 1%, of the diameter of the corresponding particle in the emulsion, including any range therebetween. In some embodiments, the diameter of the deflated particles is 0.5 pm to 15 pm, 0.9 pm to 15 pm, 1 pm to 15 pm, 2 pm to 15 pm, 2.5 pm to 15 pm, 0.5 pm to 10 pm, 0.9 pm to 10 pm, 1 pm to 10 pm, 2 pm to 10 pm, 2.5 pm to 10 pm, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0157] In some embodiments, the diameter of spherical microstmctures can be compared to the surface area of the quasi-spherical, quasi-elliptical, and irregular shape microstmctures.

[0158] As used herein, the “particle size” for a spherical particle can be defined by its diameter. With irregular and non-spherical particles, described herein, a volume-based particle size can be approximated by the diameter of a sphere that has the same volume as the non-spherical particle. Similarly, an area-based particle size can be approximated by the diameter of the sphere that has the same surface area as the non-spherical particle.

[0159] In some embodiments, the concentration of the polymer in the composition influences the shape of the microstmcture obtained in the coating. In some embodiments, the shape of the microstructure can be controlled by controlling the amount of polymer used in the composition. In some embodiments, the shape of the microstructures can be compared to a shell-like shape. In some embodiments, the shape of the microstmctures can be compared to a deflated ball-like shape.

[0160] In some embodiments, the nanostructures comprise fluorinated silica nanoparticles. In some embodiments, the nanostructures comprise silane functionalized silica nanoparticles. In some embodiments, the nanostructures comprise fluorinated silica nanoparticles and silane functionalized silica nanoparticles.

[0161] In some embodiments, the nanostructures comprise 100 % fluorinated silica nanoparticles. In some embodiments, the nanostructures comprise about 0.1 % fluorinated silica nanoparticles and about 99.9 % silane functionalized silica nanoparticles. In some embodiments, the nanostructures comprise about 0.5 % fluorinated silica nanoparticles and about 99.5 % silane functionalized silica nanoparticles. In some embodiments, the nanostructures comprise about 0.3 % fluorinated silica nanoparticles and about 99.7 % silane functionalized silica nanoparticles.

[0162] In some embodiments, the nanostructures comprise fluorinated silica nanoparticles and tricholoro(octadecyl) silane (OTS). In some embodiments, the nanostructures comprise fluorinated silica nanoparticles and OTS at a ratio between 10:1 and 1:10.

[0163] In some embodiments, the coating layer has at least one characteristic selected from: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti adhesion coating, an anti-fouling coating, a chemical resistant coating, and an anti-abrasive coating.

[0164] In some embodiments, the composition comprises an adhesiveness property to a surface. In some embodiments, the coating layer comprises an adhesiveness property to a surface.

[0165] The terms "hydrophobic surface" and "hydrophobic coating", as used herein refer to a surface or a coating that results in a water droplet forming a surface contact angle exceeding about 90 ⁰ and less than about 150 ⁰ at room temperature (about 18 to about 23 °C.). The terms "superhydrophobic surface" and "superhydrophobic coating" as used herein define surfaces which have a water contact angle above 150° but less than the theoretical maximum contact angle of about 180° at room temperature. In nature, lotus leaves are considered super hydrophobic. Water drops roll off the leaves collecting dirt along the way to give a “self-cleaning” surface. In some embodiments of the invention, the composition, the coating layer, or the article disclosed herein exhibits a contact angle on the surface of at least 130 °, 140 °, 150 °, 160 °, 165 ⁰ with an aqueous liquid, or any value therebetween. [0166] The term "anti-fouling" is referred to as an ability to inhibit (prevent), reduce or retard the growth of organisms, microorganisms and biofilm formation on a substrate's surface.

[0167] In some embodiments, at least one characteristic of the coating layer is maintained after abrasion.

[0168] In some embodiments, the superhydrophobic properties of the coating layer are maintained after abrasion. In some embodiments, the superhydrophobic properties of the coating layer are maintained after 1, 2, 5, 10, 20, 25, 30, 40, 45, 50, 55, 60, or 65 abrasion cycles. In some embodiments, at least 99%, at least 98%, at least 95%, at least 90%, at least 85%, at least 80%, at least 70%, at least 60%, or at least 50% of the superhydrophobic properties of the coating layer are maintained after abrasion. Each possibility represents a separate embodiment of the invention.

[0169] In some embodiments, the self-cleaning properties of the coating layer is maintained after abrasion. In some embodiments, the self-cleaning properties of the coating layer are maintained after 1, 2, 5, 10, 20, 25, 30, 40, 45, 50, 55, 60, or 65 abrasion cycles. Each possibility represents a separate embodiment of the invention. In some embodiments, at least 99%, at least 98%, at least 95%, at least 90%, at least 85%, at least 80%, at least 70%, at least 60%, or at least 50% of the self-cleaning properties of the coating layer is maintained after abrasion. Each possibility represents a separate embodiment of the invention.

[0170] In some embodiments, the coating layer according to the present invention, is stable to climatic changes. In some embodiments, the coating layer is stable to temperature changes, heat, cold, UV radiation and atmospheric corrosive elements. In some embodiments, the characteristics of the coating layer are not affected or altered by climatic changes as described herein. In some embodiments, the article according to the present invention, is stable to climatic changes. In some embodiments, the article is stable to temperature changes, heat, cold, UV radiation and atmospheric corrosive elements. In some embodiments, the characteristics of the article are not affected or altered by climatic changes as described herein. The method

[0171] According to some embodiments, the present invention provides a method for forming the composition described hereinabove comprising a. contacting 0.5% to 10% (w/w) of the functionalized inorganic nanoparticles with the first liquid, thereby forming a mixture; and b. contacting the mixture with the second liquid for a period of time.

[0172] In some embodiments, contacting comprises high shear mixing, ultrasonication, overhead stirring, homogenizing, or a combination thereof. In some embodiments, a period of time is 1 min to 24 hour, 5 min to 24 hour, 10 min to 24 hour, 30 min to 24 hour, 1 hour to 24 hour, 2 hour to 24 hour, 3 hour to 24 hour, 5 hour to 24 hour, 6 hour to 24 hour, 1 hour to 12 hour, 2 hour to 12 hour, 3 hour to 12 hour, 5 hour to 12 hour, 6 hour to 12 hour, 1 hour to 8 hour, 2 hour to 8 hour, 3 hour to 8 hour, or 5 hour to 8 hour, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0173] In some embodiments, the second liquid comprises 0.5% to 40% (w/w), 0.5% to 30% (w/w), 0.9% to 30% (w/w), 1% to 30% (w/w), 5% to 30% (w/w), 10% to 30% (w/w), 25% to 30% (w/w), 0.5% to 10% (w/w), 0.9% to 10% (w/w), 1% to 10% (w/w), 5% to 10% (w/w), 0.5% to 5% (w/w), 0.9% to 5% (w/w), or 1% to 5% (w/w), of the polymer, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0174] In some embodiments, the ratio of the first liquid and the second liquid is 5:1 to 1:1 (w/w), 4:1 to 1:1 (w/w), 3:1 to 1:1 (w/w), or 2:1 to 1:1 (w/w), including any range therebetween. In some embodiments, the ratio of the first liquid and the second liquid is 1: 1 (w/w). Each possibility represents a separate embodiment of the invention.

[0175] In some embodiments, the first liquid comprises oil. In some embodiments, the second liquid comprises methyl ethyl ketone (MEK), acetone, n-methyl-2-pyrrolidone (NMP), methylisobutylketone, dichloromethane or any combination thereof.

[0176] In some embodiments, the first liquid comprises oil and the second liquid comprises acetone.

[0177] In some embodiments, the ratio of the major phase and the minor phase is 5:1 to 1:1 (w/w), 4:1 to 1:1 (w/w), 3:1 to 1:1 (w/w), or 2:1 to 1:1 (w/w), including any range therebetween. In some embodiments, the ratio of the major phase and the minor phase is 1:1 (w/w). Each possibility represents a separate embodiment of the invention.

[0178] In some embodiments, the major phase comprises oil. In some embodiments, the minor phase comprises methyl ethyl ketone (MEK), acetone, n-methyl-2-pyrrolidone (NMP), methylisobutylketone, dichloromethane or any combination thereof. [0179] According to some embodiments, the present invention provides a method of coating a substrate. In some embodiments, the method comprises the steps of: i) providing a substrate; and ii) contacting the substrate with the composition as described herein, thereby forming a coating layer on the substrate.

[0180] In some embodiments, contacting is selected from the group comprising: spin coating, roll coating, spray coating, kiss coating, air knife coating, anilox coater, flexo coater, gap coating, and dipping.

[0181] According to some embodiments, the present invention provides a method of manufacturing the article described hereinabove, comprising: i) providing the composition described hereinabove; ii) contacting the composition with a substrate, thereby obtaining a coating layer on the substrate; and iii) subjecting the layer to conditions suitable for drying, thereby obtaining the article.

[0182] In some embodiments, the contacting comprises spin coating, roll coating, spray coating, kiss coating, air knife coating, anilox coater, flexo coater, gap coating, and dipping. [0183] In some embodiments, the conditions suitable for drying comprise exposing the layer to any one of air, heat, vacuum, thermal irradiation, microwave irradiation, infra-red irradiation, and UV-visible irradiation, or any combination thereof.

[0184] In some embodiments, the substrates comprising a coating layer are placed in hot air oven. In some embodiments, the substrates comprising a coating layer are placed in a hot air oven at a temperature ranging from 20°C to 180°C, 25 °C to 180°C, 30°C to 180°C, 30°C to 150°C, 30°C to 90°C, 30°C to 80°C, 30°C to 70°C, 30°C to 60°C, 40°C to 180°C, 40°C to 150°C, 40°C to 90°C, 40°C to 80°C, 40°C to 70°C, 40°C to 60°C, 50°C to 180°C, 50°C to 150°C, 50°C to 90°C, 50°C to 80°C, 50°C to 70°C, or 50°C to 60°C, including any range therebetween. Each possibility represents a separate embodiment of the invention. In some embodiments, the substrates comprising a coating layer are placed in hot air oven for a period of time in the rage of 1 hour to 24 hour, 2 hour to 24 hour, 3 hour to 24 hour, 5 hour to 24 hour, 6 hour to 24 hour, 1 hour to 12 hour, 2 hour to 12 hour, 3 hour to 12 hour, 5 hour to 12 hour, 6 hour to 12 hour, 1 hour to 8 hour, 2 hour to 8 hour, 3 hour to 8 hour, or 5 hour to 8 hour, including any range therebetween. Each possibility represents a separate embodiment of the invention.

[0185] In some embodiments, the substrate is selected from the group comprising: a polymeric substrate, glass substrate, a metallic substrate, a paper substrate, a carton substrate, a brick wall, a sponge, a textile, or wood. [0186] In some embodiments, the coated substrate has at least one characteristic selected from: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti adhesion coating, an anti-fouling coating, a drag reduction coating, an anti-corrosion coating, an anti-wetting coating, an oil-water separation coating, an anti-fogging coating, a chemical resistant coating, and an anti-abrasive coating.

[0187] In some embodiments, the coating layer has at least one characteristic selected from: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti adhesion coating, an anti-fouling coating, a drag reduction coating, an anti-corrosion coating, an anti-wetting coating, an oil-water separation coating, an anti-fogging coating, a chemical resistant coating, and an anti-abrasive coating.

General

[0188] As used herein the term “about” refers to ± 10 %.

[0189] The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

[0190] The term “consisting of means “including and limited to”.

[0191] The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

[0192] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.

[0193] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.

[0194] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

[0195] Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. [0196] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

[0197] As used herein the term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts.

[0198] As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition.

[0199] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0200] Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.

EXAMPLES

[0201] Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non-limiting fashion. Materials and methods Miscibility of oil pairs

[0202] Equal volumes (5mL) of an oil and methyl ethyl ketone were placed in a screw- cap glass vial. The mixture was sonicated for 10 min using an ultra- sonication at 25% amplitude. The volume of the two oil phases was separated after few minutes and measured. Synthesis ofF-Si02 nanoparticles (NPs)

[0203] lg Silica NPs was dispersed in 40mL of ethanol by mechanical mixing. 32.64 mmol (1.14g) of NH4OH (28 wt%) was added slowly to the solution. After ten minutes, 2.58 mmol (1.32g) of lH,lH,2H,2H-Perfluorooctyltriethoxysilane (FAS) was added to the solution. The reaction was performed at ambient temperature for 45 min, followed by vigorous stirring (800 rpm). The fluorocarbon functionalized silica particles are collected by four cycles of centrifugation followed by ethanol rinsing. The NPs are then dried in a vacuum oven at 35°C for ca. 3 hours.

Preparation of emulsions

[0204] The emulsions are prepared changing the silica (1, 3, 5 wt%), polymer (5, 10, 30 wt%) and both oil ratio (1-9 mL). 1, 3 and 5 wt% silica dispersed in oil in the presence of 5, 10 and 30 wt% polymer according to MEK volume, are investigated. The silica dispersion was prepared as follows; required mass of particles are placed in the vial followed by addition of the required mass of oil. The mixture was sonicated for lOmin. The required volume (5mL) of MEK and chosen amount of polymer was then added. The mixture was sonicated for 10 min using an ultra- sonication at 25% amplitude.

Preparation of coatings

[0205] The prepared emulsions are applied on the surface (2 X 2 cm, 150 pL) via spin or roll coating method. In order to enable rapid evaporation of emulsions, the surfaces are placed in hot air oven maintained at 60°C for 3+1 hour.

Fourier transform infrared (FTIR) spectroscopy analysis

[0206] The surface modification of the S1O2 nanoparticles was analyzed by elucidating the molecular structure of the covalently attached organosilanes, using Thermo ScientificTM NicoletTM iS50 FTIR spectrometer, equipped with attenuated total reflection (ATR) module (smart iTX - Diamond).

Emulsion characterization

Cryogenic-scanning electron microscopy ( cryo-SEM )

[0207] Cryogenic-scanning electron microscopy analysis was performed on a JSM-7800F Schottky field-emission SEM microscope (Jeol Ltd., Tokyo/Japan), equipped with a cryogenic system (Quorum PP3010, Quorum Technologies Ltd., Laughton/ United Kingdom). Liquid nitrogen was used in all heat exchange units of the cryogenic system. A small droplet of emulsion was placed on the sample holder, between two rivets, quickly frozen in liquid nitrogen for a few seconds and transferred to the preparation chamber where it was fractured (at -140 °C). The revealed fractured surface was sublimed at -90 °C for 10 min to eliminate any presence of condensed ice, and then coated with platinum. The temperature of the sample was kept at -140 °C. Images were acquired with a low electron detector (LED) at an accelerating voltage of 5.0 kV and a working distance of 3.9 mm. Energy-dispersive X-ray spectroscopy (EDX) analysis was performed with a LED detector at an accelerating voltage of 5.0 kV and a working distance of 9.9 mm.

Confocal laser scanning microscopy ( CLSM) analysis

[0208] Image acquisition was done using a Leica SP8 laser scanning microscope (Leica, Wetzlar, Germany), equipped with a solid state laser with 488 nm light , HC PL APO CS 20x/0.75 objective (Leica, Wetzlar, Germany) and Leica Application Suite X software (LASX, Leica, Wetzlar, Germany). Imaging of Nile Red signal was done using a solid state laser with 552 nm light, and the emission was detected in the range of 580-670 nm. Lor the analysis, 5 pL was taken from emulsion and drop-cast on a microscopic slide, equipped with a coverslip. Droplet size distribution wasanalyzed using Liji software by measuring the droplet diameters from confocal microscopy images for each emulsion type. The optical micrographs of each samples was used to determine the droplet size of the emulsions by averaging the diameter of 100 emulsion droplets using the particles analysis tool of Liji software and plotted as a graph with Origin (OriginLab, Northampton, MA). Morphological characterization

[0209] SEM images of fabricated coatings are obtained using a model MIRA3 from TESCAN at a 1 & 5 kV accelerating voltage respectively. In order to prepare samples for SEM analysis, the Pickering emulsion coated surface are deposited onto aluminum sample holder covered with carbon tape. The samples were sputter-coated with a gold-palladium, to reduce charging effects.

Wetting analysis

[0210] To study the surface wettability, static water CAs and RAs was measured at room temperature using a drop shape analyser (DSA 100 Kruss). 5pL water (AR Grade) droplets dispensed on the coatings surface and side view images of them are captured. Lor measuring, water RAs, the stage was tilted followed by deposition of 5pL water droplets onto the surface. RAs are recorded as a stage tilt angle at which all the water droplets stared roll away from the coating surface.

EXAMPLE 1

Superhydrophobic coating based on emulsion templating of 0/0 Pickering emulsion

[0211] Polyacrylate/PVC (Rowaakryl M-33697) was dissolved in MEK (Methyl ethyl ketone) at different concentrations (5, 10, 30 wt%). Subsequently, F-SiCh (Fluoro functionalized silica) nanoparticles are dispersed in Oil at different concentrations (1, 3, 5 wt%) by ultrasonication. The resulting MEK polymer solutions are mixed with the Oil dispersions, by second ultrasonication at different ratios to form stable 0/0 Pickering emulsions.

[0212] The F-S1O2 are prepared by surface functionalization of commercial pristine silica nanoparticles (Evonik, Germany). The successful covalent immobilization of fluorosilane molecules onto the silica NPs was confirmed by FTIR (Figure 2). The peak at 1040 cm^-1 is due to asymmetric stretching vibration of Si-O-Si bonds in silica nanoparticles. Another small peak appearing at 795 cm ¹ is associated with the bending mode of Si-O-Si bonds. In addition, peak at 430 cm ¹ is associated with Si-O-Si bond for the rocking vibration. After functionalized with fluorosilane, a peak at 900 cm ¹ assigned to C-H bonds. The existence of C-F bonds in the form of CF, CF2 or CF3 can be confirmed by peaks located at 644, 730, 957 and 1241cm ¹. The peak at 1176 cm ¹ represents the Si-O-C bond, which confirms that the fluorosilane molecule was attached to the silica NPs.

[0213] Table 1 depicts the different emulsion compositions prepared and characterized. The emulsions at MEK/oil phase ratio of 1:1 have shown significant stability for approximately 60 days, and therefore were further investigated in this study.

Table 1. The different Pickering emulsion compositions prepared in the study.

EXAMPLE 2

Wettability and surface wetting characterization

[0214] The stable emulsions are directly applied on Polypropylene (PP) and Polycarbonate (PC) surfaces via drop casting method, and dried in an oven for three hours at 150 °C to form nanocomposite coatings on top of the polymeric substrates. The wetting characteristic of the resulting coatings was studied by characterization of their static water contact angle.

[0215] The behavior of superhydrophobicity results from a combination of hierarchical nano and micron scale roughness along with a hydrophobic nature of the surface. The main parameter that defines the durability of the superhydrophobic surface, is its abrasion resistance, i.e., the ability to maintain the property of superhydrophobicity upon introduction of abrasion on the coated surface. During abrasion, both the topography and the chemical nature of the surface might be altered, leading to elimination of the superhydrophobic property. Therefore, there is a great motivation to develop superhydrophobic surfaces which will maintain their surface roughness and chemical nature after mechanical abrasion to form durable superhydrophobic coatings. Additional important parameters which represent the durability of the superhydrophobic surface are resistance to chemicals and harsh environmental conditions. The abrasion resistance of the coatings that were applied on PP and PC surfaces has been studied by finger wipe test (a rubber glove was used as an abradant; while abradant moves, the sample stays stationary). EXAMPLE 3

Effect of surface micro-nano structure & surface chemistry on superhydrophobic behavior

[0216] In this study, fluorocarbon functionalized silica nanoparticles attributed for the lower surface energy. The functional groups (-CF2, -CF3) could reduce the adhesive interaction, inevitably prevent the liquid droplets penetrate into the micro structure and provide the surface with superhydrophobicity. The deflated seashell to deflate rugby ball micro-nano structure may be obtained according to change in polymer concentration as seen above. The effect of surface micro-nano structure and surface chemistry may enhance superhydrophobic behavior of emulsion applied polymeric surfaces. The deflated structure may assist to entrap air and thus reduce the contact area between droplet and coated surface.

EXAMPLE 4

Chemical stability and Durability

[0217] Micro/nanoscale structure plays important role for superhydrophobic properties in coatings. However, low durability and ease of damage decreases the application of superhydrophobic coatings. Adhesives were implemented to bind coating to the substrate to improve robustness of coating. Nevertheless, if the adhesive and coating are individually applied on the polymer substrate, the coating process becomes complicated and affects the competence of large-scale production. Here, the polymer acts as adhesive, and the oil enhances the robustness of the resulting superhydrophobic coating and simplifies the coating process.

EXAMPLE 5

Superhydrophobic coating based on emulsion templating of O/O Pickering emulsion

[0218] Polyacrylate/PVC was dissolved in MEK (Methyl ethyl ketone) at different concentrations (5, 10, 30 wt%). Subsequently, F-SiCh (FAS) and

Tricholoro(octadecyl) silane (OTS ; CAS number 112-04-9) nanoparticles at a 1 : 1 ratio were dispersed in mineral oil (3 wt%) by ultrasonic ation. The resulting MEK polymer solutions are mixed with the Oil dispersions, by second ultrasonication at different ratios to form stable O/O Pickering emulsions. [0219] Figures 4A-F show confocal microscopy analysis of samples prepared as described herein. Figures 5-7 provide SEM images of the emulsions of the invention incorporating 5wt%, 10wt% and 30wt% polymer, respectively, coated on polypropylene (PP) surfaces. [0220] Figures 8A-C and Figures 9A-B present wettability properties of the emulsions described herein incorporating 5wt%, 10wt% and 30wt% polymer, when coated on a PP surface. The described emulsions incorporating 5% - 30% of the thermoplastic polymer within the core, acted as superhydrophobic coating.

EXAMPLE 6

Emulsions stabilized by multi-functional particles

[0221] The type of emulsions stabilized by multi-functional particles at different oil volume fractions are shown in Table 2.

Table 2. Summary of emulsions stabilized by multi-functional particles at different oil volume fractions and polymer (P).

O -

Acetone; P - Polymer; A/O - acetone-in-oil; O/A - oil-in-acetone;

O/A/O - oil-in-acetone-in-oil; A/O/A - acetone-in- oil-acetone.

EXAMPLE 7

Conditions for phase inversion

[0222] At the volume fractions _</_acc at 0.5, simple acetone/mineral oil (A/O) emulsion were formed (with particle concentration of 3wt %), if the particles were wetted by acetone first. Conversely, with _{< Cc} at 0.3, A/O, mineral oil/acetone/mineral oil (O/A/O) multiple emulsion formed whereas, _{< Cc} at < 0.3 no emulsion formation was observed for all concentration range of particles.

[0223] Multiple emulsion droplets were observed as the particle concentration was increased. For example, ^_ace at 0.5, mixing an acetone dispersion of particles with mineral oil formed mineral oil-in-acetone (O/A), acetone-in-mineral oil-in- acetone (A/O/A), O/A, A/O and O/A/O emulsions at particle concentrations of 4, and 5 wt%, respectively. The multiple droplets tended to be spherical in shape and larger in size than the simple A/O or O/A droplets.

EXAMPLE 8

Effect of initial location of particle

[0224] The type of emulsion formed at intermediate drop volume fractions (also called the ambivalent region) showed a dependency on the type the liquid initially used to wet the particles and the mixing power.

[0225] For example, the particles wetted by acetone initially, at volume fractions ^_ace 0.5, form a simple A/O emulsion. In contrast, multiple emulsion of O/A, A/O/A were formed in particles wetted by oil initially at 3 and 4wt% particle concentration (Figures 10G-I). With higher silica concentration, the emulsion resulted in jammed structure (Figure 101). An initial oil dispersion of the particles, increases the particle hydrophobicity due to the hydrophobic carbon like behavior. At higher concentrations of silica, a three- dimensional network of flocks spread all through the sample volume and the suspension can be considered gel-like. The viscosity of the particle concentration showed a dependency on two factors - particle hydrophobicity and liquid polarity. Hence, when partially hydrophobic particles were in a nonpolar liquid like mineral oil, an emulsion was formed as a result of gel like behavior due to particle -particle interactions on the adjacent particles forming aggregates.

EXAMPLE 9

Impact of polymer concentration

[0226] While increasing the polymer concentration in the emulsion, a phase inversion behavior was observed (Figures 10D-F). In an equal volume fraction of acetone and mineral oil, and at 30wt % of polymer concentration, an O/A emulsion was formed in 3, 4 and 5 wt % silica concentration. [0227] The increase in viscosity of a phase, influenced its shift from dispersed to continuous phase. In addition, phases with large density differences also showed increased tendency to undergo phase inversion. The increasing viscosity of the phase induced silica aggregates to change their hydrophobicity behavior resulting in phase inversion.

[0228] The excess of polymer molecules present in acetone phase were expected to be adsorb at oil in acetone interfaces. This behavior resulted in polymer particles adsorbed as a dense layer around the oil droplets. Such dense layer exhibited a viscoelastic behavior and the interaction between the polymer and particles at the interface may facilitate aggregation or increase the hydrophobicity of particles rendering phase inversion.

[0229] Increasing the polymer concentration from 5, 10, to 30 wt % at 4 wt % silica, with equal volume of oils based emulsion, phase inversion behavior was observed (Figure 10K). At 5% and 10% polymer concentration A/O, O/A/O and O/A, A/O/A multiple emulsions were formed. At 30wt % polymer concentration simple inverse O/A emulsion was formed.

EXAMPLE 10

Effect of particle concentration on multiple emulsion formation

[0230] The distribution of drop size in simple and multiple emulsions revealed further information about the conditions leading to multiple drop formation. Figure 10J shows the data for emulsions stabilized by particles initially wet by acetone or oil. At low concentrations of particles (3 wt %), simple A/O emulsions were formed. With the increase in polymer concentration (30wt %), O/A emulsion was obtained and the mean drop size decreased with the increasing of particle concentration (Figure 10J triangle line). At higher concentrations of particles (4, 5wt %) multiple emulsions were obtained. As particle concentration increases, the number of encapsulated drops, and hence size of the globules (oil or acetone) increased. There was little evidence of excess particles located in either the bulk acetone or oil phases over the particle concentration range studied (3 < P < 5wt %). This indicates that, most particles were attached to interfaces. Therefore, the size of oil globules or acetone globules increased with particle concentration (Figure 10J square line). The uniformity of drop size distribution increased, indicating oil or acetone globules are increasingly polydisperse. The increase in globules size with particle concentration suggests that, coalescence dominates fragmentation during mixing. In this emulsification regime, coalescence process is not limited by particle coverage on globule surfaces. Hence, polydispersity is likely due to the increasing number of small acetone or oil droplets being encapsulated in the oil or acetone globules respectively. In contrast, multiple emulsion formed as particles wetted by oil initially, droplets size decreased as particle concentration increased (Figure 10J circle line).

EXAMPLE 11

Catastrophic phase inversion

[0231] The confocal images shown in Figures 11D-F illustrate how a versatile multi functional silica can form single and multiple emulsions depending on the internal volume fraction of acetone. At the volume fraction of acetone c|)ace - 0.3, stable A/O, O/A/O multiple emulsion were formed at all silica concentrations. At 5wt% silica concentration spherical droplets were formed, distorted droplets were observed at 3 & 4 wt% silica concentration (Figures 11D-F). At the volume fraction of acetone ([acc - 0.4 (Figure 11A- C), stable A/O emulsion was obtained in 3wt% silica concentration. Inversely, A/O, O/A/O multiple emulsion were formed at 4 & 5wt% silica concentrations. At the volume fraction of acetone c|)ace - 0.5, stable A/O emulsion formed in 3wt % silica concentration. The catastrophic phase inversion phenomenon was observed in 4wt% and 5wt% silica concentrations. Inverse O/A, A/O/A multiple emulsions were obtained.

EXAMPLE 12

Function of particles hydrophobicity

[0232] In the present study, emulsions with varying degree of hydrophobic silica (fully functionalized fluoro silica (100%) and multi-functional silica (70:30 and 50:50) were stabilized using same conditions. Interestingly, 100% and 70:30 silica based emulsions were stabilized as O/A and 50:50 based silica stabilized emulsion as A/O (Figure 11G-I). This behavior is due to the hydrophobicity of the particles. The more hydrophobic nature of silica particles disperse freely in acetone and not in mineral oil. This is an evidence of bi-wettable behavior of the multi-functional (50:50) particles. The presence of the alkyl chain functional groups helps the particles to disperse in mineral oil readily.

EXAMPLE 13 Anisotropic microstructures

[0233] Interestingly, with the polymer and/or silica concentration increase, the inventors observed elongated emulsion droplets in confocal microscopy. Complete merging of two emulsion droplets can be halted in the intermediary stage, provided the Laplace pressure is counteracted by the rheological resistance in emulsion. The obtained arrested coalescence structure resembles a stable doublet that is a snapshot of an intermediate state of the coalescence process.

[0234] From confocal and Cryo-SEM microscopy analysis of emulsion, the inventors observed that, the shapes of larger coalescence drops mirrors the intermediate stage of coalescence process. It indicated that, coalescence was arrested before fusion into spherical shape. Interestingly, same anisotropic structures were observed in SEM analysis after the surface coated with the emulsion was dried. This revealed the formation of stable arrested coalescence droplet. The formation of structures similar to fish, dumbbell, oval were observed. In this study, arrested coalescence behavior was noticed with increase in silica or higher polymer concentration. For instance, in 3wt% silica concentration, at higher polymer concentration (30wt%) arrested coalescence was observed. Formation of arrested coalescence is due to jamming of particles at oil-water interface and droplet micro structure balance between interfacial driving force and elastic reaction force. As indicated in the results, when polymer increases in dispersed phase, the increase in viscoelastic behavior of droplets initiates coalescence and balance between the interfacial energy and elastic reaction force to form stable arrested doublets. On other hand, with increase in silica concentration, the droplet surface to volume ratio increases as particle coverage increases on droplet surface during fusion process. Formation of stable anisotropic shapes is based on the capability of jammed particles to tolerate unequal stress along oil-water interface.

EXAMPLE 14

Morphology of the multiple emulsion droplets

[0235] The nanostructure of the Pickering emulsions was characterized via direct imaging using high-resolution Cryo-SEM (Figures 13A-F). This method enabled the direct observation of the emulsion structure by ultrafast cooling of vitrified cryo-SEM specimens. In order to investigate the interface structure, the acetone phase was evaporated via sublimation resulting in exposure of the interface. The multiple emulsions that formed in the ambivalent region consist of large, (mostly) spherical globules of oil that contained spherical droplets of acetone or vice versa. The external and internal surfaces of the multiple drops were coated with particles, as shown in Figures 13A-F. As the particle concentration increases, the number of encapsulated drops and hence the size of the globules increases. There was little evidence of excess particles located in either the bulk acetone or mineral oil phases over the particle concentration range studied (< 3wt %). This indicates that most of the particles are attached to the interfaces. [0236] The multifunctional particles formed rough, dense layers of closely packed particles at the (outer) acetone-in-oil interfaces of the multiple droplets, as shown in Figure 13E. The particles attached to the (inner) acetone-in-oil interfaces were strongly flocculated, as shown in Figure 13C. Some of the regions of the inner interfaces were thickly coated with flocks that were connected together across the surface. Other regions were less densely coated, but there were no particle-free regions. The images at low magnification showed sublimation of acetone in fractured sample, thus, making it possible to see the presence of a meshed or tangled network of polymers in the inner side of the droplets (Figure 13A). In figure 13C, it can be observed the dense layer formed by polymer particles at the interface. This observation confirms the inventors preceding discussion on phase inversion owing to increase in polymer concentration.

EXAMPLE 15

Mechanism of double emulsion formation

[0237] The designed FAS-OTS modified multi-functional silica shown here provide a unique feature that stabilizes multiple emulsion droplets. Although moderate hydrophobic (lipophilic) OTS (Cl 8 carbon) block was dispersed in both mineral oil and acetone, OTS modified silica was expected to be preferentially wetted by oil phase that allows the migration of the particles from the initial oil phase to the acetone-oil interface, stabilizing both the outer O/A (oil/acetone) and inner A/O (acetone/oil) droplets, as schematically described in Figure 14. In addition, FAS was chosen as a hydrophobic block because it disperses in acetone rather than mineral oil. The high dispersibility of the FAS chain in the acetone phase could facilitate the extension of the OTS chain to outer oil phase in order to shield the FAS blocks interaction with oil phase. As a result, the more extended conformation of FAS in the acetone phase significantly enhances the stability of outer O/A (oil/acetone) emulsion through the steric repulsion mechanism. Similarly, in the inner acetone droplets, the extension of the OTS chain to the oil phase was also facilitated as the FAS block was shielded from interactions with acetone. This shielding effect leads to a more extended conformation of OTS in the oil phase and allows the efficient stabilization of the inner acetone droplets. The current designed particles thereby differ greatly from typical Janus like particles stabilized emulsions where single component particles or surfactants generally do not stabilize multiple emulsion droplets. Another important feature of using FAS-OTS modified multi-functional silica particles to stabilize the multiple emulsions is that both FAS and OTS blocks are soluble in acetone. In contrast to the typical surfactants, no reverse micelles are formed in the middle acetone phase. This striking difference can account for the longer shelf life of the current formulated emulsion because there is no well dispersion of the particles in the oil phase and interfaces, which eventually prevents the rupture of oil membrane and loss of the internal droplets.

EXAMPLE 16

Structural characterization of double emulsion

[0238] The morphologies of surfaces coated with O/O, double (O/O/O) Pickering emulsion were assessed by scanning electron microscopy (SEM). Multi-functional particles coated craters and deflated structure were observed, after evaporation of acetone from emulsion as shown in Figures 15A-R. Comparing the change in droplet average diameter of emulsion before (optical microscopy) and after cured (SEM), the average droplet diameter change was analyzed. Figure 16, shows the change in droplet diameter in optical microscopy and SEM.

[0239] To understand the formation of spherical and deflated structure after evaporation of acetone. This observation led to the curiosity to identify how the droplets spherical morphology changed into deflated structure.

[0240] Results from the present study and pervious reports indicate that, droplet deflation governed by the interaction between the adsorbed silica particles and polymer at interface. Various structures such as spherical and deflated were obtained with varying silica and polymer concentrations. In lower silica content-based emulsion (1:1 system) with varying polymer concentration, A/O or O/A (acetone/oil, or oil/acetone) were formed with spherical and non- spherical structure due to the weak interaction between silica and polymer at the interface. In higher silica (5wt %), content based multiple emulsions (A/O/A) formed deflated structures duo to the strong interaction between the particle polymers at the interface. In mineral oil: acetone (6:4) based system spherical structures were formed. [0241] Interestingly, inverse emulsions (mineral oil/acetone), and formation of porous structure after solvent evaporation were observed while increasing the polymer concentration in the system as shown in Figures 12A-I.

[0242] In the evaporation process, since acetone was evaporated prior to mineral oil, the droplets became increasingly concentrated and gradually transformed into concentrated emulsions. Further evaporating acetone and mineral oil could form the porous structure. The pores resulted from a loss of the oil phase. Even though the production of pore throats was a relatively complex process, it was believed that the pore throats formed at the contact regions of neighboring droplets.

[0243] The increase of polymer molecules present in the acetone phase were expected to adsorb at acetone in oil interfaces. This behavior resulted of polymer particles adsorbed as a dense layer around the oil droplets as seen in the Cryo-SEM images. Such dense layer exhibited a viscoelastic behavior helping to form a jammed template that could be directly converted in to porous structure upon drying.

[0244] While drying the applied emulsion, the oil droplets came in close contact with each other as the acetone evaporates, as emulsion compresses, the oil droplets start to deform into hexagons. As the acetone evaporates, the film separating the droplets becomes thinner and thinner, coalescence occurs and the excess particles and polymer in the acetone are trapped at the droplet surface. The polymer formed a shell around the oil droplets, so once full coverage is achieved, the remaining polymer created a viscoelastic network in the continuous phase. The increase in polymer concentration contributed in two factors to form this structure: the reduced acetone evaporation and the formation of a tighter polymer network. The entrapment of acetone into the polymer network resulted in reduced acetone evaporation. Simultaneously, interaction between the particles and polymer matrix increased forming tighter polymer network between the droplets.

[0245] As per earlier discussion, anisotropic structures of arrested coalescence droplets were assessed in SEM analysis. The structures look akin to coffee bean, neuron, fish, pumpkin, oval, peanut, dumbbell (Figures 17A-C). This observation confirms the formation of stable arrested coalescence. Triplet arrested coalescences is addition of the third droplet to the arrested droplet doublets. In this study, the inventors observed the formation of triplet arrested coalescence as a similar to a Neuron structure (figure 17C).

[0246] Results from the present study and pervious reports indicate that, droplet deflation is governed by the interaction between the adsorbed silica particles and polymer at interface. Various deflated structures were obtained with varying polymer concentrations. This phenomenon invariably suggested strong interaction between the polymer and multi functional silica nanoparticles at the interfacial area. These results led to the curiosity to identify the silica particles polymer interaction at the interface. EXAMPLE 17

Interaction between the polymer and particles at the interface

[0247] The Cryo-SEM analysis (Figures 18A-B) was used to identify any interaction between the particle and polymer at the interface. This result confirms that droplet deflation is directed by interaction between multi-functional silica particles and polymer at interface. Hence, this observation consistently suggested that interaction between particles and polymer at interface led to the formation of different morphology of droplet structures after evaporation of the acetone. These deflated structures of coating material enhances the superhydrophobic behavior of the surface. In addition, micro/nano structured surface texture (depicted here by deflated structures) and multifunctional-SiC adsorbed on these structures supports to trap a thin air layer that reduces attractive interactions between the solid surface and the liquid.

EXAMPLE 18

Wettability behavior of coated surfaces

[0248] The stable emulsions were directly applied on polypropylene (PP) surfaces via spin coating method, have been dried in an oven for 4+1 hours at 90°C to form nanocomposite coatings on top of the polymeric substrates. The wetting characteristic of the resulting coatings have been studied by characterization of their static water contact angle (WCA). Figures 19A-F depicts the WCA and the roll off (RA) angles of the different studied systems. From the observation of WCA and RA analysis, all 21 samples showing superhydrophobicity (WCA 145°±2° to 155°±2°, RA < 10). The behavior of superhydrophobicity results from a combination of hierarchical nano and micron scale roughness along with a hydrophobic nature of the surface.

[0249] To identify the most promising possibilities of mechanically robust and durable superhydrophobic coatings, the samples were further examined to primary abrasion test (Finger wipe test). Figures 19A-F depict the results of WCA and RA values of the different coatings after finger wipe test. After four-time finger wipe abrasion on each surfaces, 13 coatings persisted their superhydrophobic behavior and remaining two lost their superhydrophobic nature and became hydrophobic surfaces. This was clearly visible by change in the WCA 155°±2° to 136°±6° and RA > 20°. The 13 samples were further examined for 8-cycle finger wipe. Out of 13 samples, only six samples retained their superhydrophobic behavior and remaining lost their superhydrophobic nature. This was clearly identified by change in the WCA 142°±2° to 128°±4° and RA > 30°. Table 3 represents the list of the successful emulsions after 8- cycle finger wipe test.

Table 3. List of the successful emulsions after abrasion (eight times finger wipe) test.

EXAMPLE 19

Effect of micro-nano structure and surface chemistry on superhydrophobic behavior

[0250] In this study, fluorocarbon, hydrocarbon multi-functionalized silica nanoparticles were used. The functional groups (-CF2, -CF3,-CH2, -CH3) could reduce the adhesive interaction, inevitably prevent the liquid droplets to penetrate into the micro structure and provide the surface with superhydrophobicity. The deflated micro-nano structures were achieved according to change in polymer concentration and silica content (type of emulsion). The synergistic effect of surface micro-nano structures and surface chemistry enhanced superhydrophobic behavior of the emulsions applied on polymeric surfaces. Additionally, the deflated structure assisted to entrap air and thus reduce the contact area between droplet and coated surface. In the present process, structures similar to a concave structure were obtained from emulsion template and the diameter of the concave can be controlled by altering silica and polymer concentration. For example, in acetone/oil/acetone double emulsion template, the inventors achieved the concave along with deflated structure. The micro-nano hierarchical structures obtained in the present study could be applied to fabrication of superhydrophobic surface owing to their geometrical structure. Figures 20A- L show images of water droplets on a) smooth surface b) emulsion structure and c) deflate double emulsion (concave along with spherical/deflated) structure. Figure 20F presents the WCA of uncoated polypropylene surface, Figure 20G presents the WCA of emulsion- coated polypropylene surface with deflated spherical structure, and Figure 20H presents the WCA of emulsion-coated polypropylene surface with deflated concave along with spherical structure.

[0251] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0252] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

1. A particle comprising a core and a shell, wherein: a. said particle is characterized by an average diameter between 5 pm and 100 pm; b. said shell comprises functionalized inorganic nanoparticles and is characterized by a thickness between 5 nm and 100 nm; and c. said core comprises between 1% and 40% weight per weight (w/w) of a thermoplastic polymer.

2. The particle of claim 1, comprising between 1% and 10% (w/w) of said functionalized inorganic nanoparticles.

3. The particle of any one of claims 1 or 2, wherein the ratio of said nanoparticles to said thermoplastic polymer is between 1:0.01 and 1:10 (w/w).

4. The particle of any one of claims 1 to 3, wherein said shell comprises an outer layer of said thermoplastic polymer.

5. The particle of any one of claims 1 to 4, wherein said functionalized is selected from halogen-functionalized, halocarbon-functionalized, alkyl-functionalized, silane- functionalized, alkoxy silane-functionalized, or any combination thereof.

6. The particle of any one of claims 1 to 5, wherein said functionalized is perfluorooctyltriethoxy silane (FAS) functionalized, tricholoro(octadecyl) silane (OTS), or both.

7. The particle of any one of claims 1 to 6, wherein said functionalized is perfluorooctyltriethoxy silane (FAS) functionalized and tricholoro(octadecyl) silane (OTS) at a ratio between 3:1 and 1:1 (w/w).

8. The particle of any one of claims 1 to 7, wherein said inorganic nanoparticles are selected from the group consisting of silica, aluminum oxide, iron oxide, zirconium oxide, titanium oxide, clay, and any combination thereof.

9. The particle of any one of claims 1 to 8, wherein said core comprises at least two layers of said thermoplastic polymer.

10. The particle of any one of claims 1 to 9, wherein said thermoplastic polymer comprises a polyacrylate, polysiloxane, polyethylene, polyisocyanate, polyurethane, fluorinated polymer, perfluorinated polymer, Teflon, Teflon PTFE, polyvinylchloride, polydimethylsiloxane, polystyrene, polytetrafluoroethylene, or any combination thereof.

11. The particle of any one of claims 1 to 10, characterized by a spherical shape, a quasi- spherical shape, a quasi-elliptical sphere, a deflated shape, a concave shape, an irregular shape, or any combination thereof.

12. A composition comprising the particle of any one of claims 1 to 11, a first liquid and a second liquid, wherein said particle is in the interface of said first liquid and said second liquid.

13. The composition of claim 12, wherein the ratio of said first liquid and said second liquid is between 5:1 and 1:1 (w/w).

14. The composition of any one of claims 12 or 13, wherein said composition is a dispersion or an emulsion.

15. The composition of any one of claims 12 to 14, wherein said first liquid comprises a mineral oil, hydrocarbon, fatty acid, mono-, di-, triacylglycerols, vegetable oil, wax, essential oil, aromatic oil, or any combination thereof.

16. The composition of any one of claims 12 to 15, wherein said second liquid comprises methyl ethyl ketone (MEK), acetone, n-methyl-2-pyrrolidone (NMP), methylisobutylketone, dichloromethane, or any combination thereof.

17. The composition of any one of claims 12 to 16, wherein said second liquid comprises said thermoplastic polymer.

18. The composition of any one of claims 12 to 17, wherein said second liquid comprises acetone.

19. The composition of claim 18, wherein said composition is selected from the group consisting of an oil-in-oil (O/O) emulsion, acetone-in-oil (A/O) emulsion, oil-in- acetone (O/A) emulsion, oil-in-acetone-in-oil (O/A/O) emulsion, acetone-in- oil- acetone (A/O/A) emulsion, and any combination thereof.

20. An article comprising: a substrate in contact with a coating layer, wherein said coating layer comprises (i) a particle of any one of claims 1 to 11 or (ii) the composition of any one of claims 12 to 19.

21. The article of claim 20, wherein said coating comprises a plurality of dry particles bound to said substrate.

22. The article of any one of claims 20 or 21, wherein said dry particles are devoid of said first liquid and said second liquid.

23. The article of any one of claims 20 to 22, wherein said dry particles are characterized by concave porous structures.

24. The article of any one of claims 20 to 23, wherein said coating layer is characterized by an average thickness between 10 nm and 400 pm.

25. The article of any one of claims 20 to 24, wherein said coating layer is characterized by a water contact angle (WCA) in the range of 120° to 180°.

26. The article of any one of claims 20 to 25, wherein said coating layer is characterized by a roll-off (RA) angle of less than 10°.

27. The article of any one of claims 20 to 26, wherein said coating layer is stable at a temperature range of -100°C to 1500°C.

28. The article of any one of claims 20 to 27, wherein said coating layer is characterized by a transparency of 30% to 100%.

29. A method for forming the composition of any one of claims 12 to 19, comprising: a. contacting 0.5% to 10% (w/w) of said functionalized inorganic nanoparticles with said first liquid, thereby forming a mixture; and b. contacting said mixture with said second liquid for a period of time.

30. The method of claim 29, wherein said contacting comprises high shear mixing, ultrasonication, overhead stirring, homogenizing, or a combination thereof.

31. The method of any one of claims 29 or 30, wherein said second liquid comprises 0.5% to 40% (w/w) of a thermoplastic polymer.

32. The method of any one of claims 29 to 31, wherein the ratio of said first liquid and said second liquid is 5:1 to 1:1 (w/w).

33. A method of manufacturing the article of any one of claims 20 to 28, comprising: i) providing the composition of any one of claims 12 to 19; ii) contacting said composition with a substrate, thereby obtaining a coating layer on said substrate; and iii) subjecting said layer to conditions suitable for drying, thereby obtaining said article.

34. The method of claim 33, wherein said contacting comprises spin coating, roll coating, spray coating, kiss coating, air knife coating, anilox coater, flexo coater, gap coating, and dipping.

35. The method of any one of claims 33 or 34, wherein said substrate is selected from the group comprising: a polymeric substrate, glass substrate, a metallic substrate, a paper substrate, a carton substrate, a tissue-based substrate, a brick wall, a sponge, a textile, or wood.

36. The method of any one of claims 33 to 35, wherein said conditions suitable for drying comprise exposing said layer to any one of air, heat, vacuum, thermal irradiation, microwave irradiation, infra-red irradiation, and UV- visible irradiation, or any combination thereof.

37. The method of any one of claims 33 to 36, wherein said coating layer has at least one characteristic selected from: a superhydrophobic coating, a self-cleaning coating, an anti-icing coating, an anti-adhesion coating, an anti-fouling coating, a drag reduction coating, an anti-corrosion coating, an anti-wetting coating, an oil-water separation coating, an anti-fogging coating, a chemical resistant coating, and an anti-abrasive coating.