# US 2014/0193651 A1 · MULTILAYER HYDROGELS WITH pH-RESPONSIVE SWELLING AND SURFACE WETTABILITY > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193651 A1 - Document ID: US20140193651A1 - Status: Published application - Kind: A1 - Application number: 13/798,870 - Filed: 2013-03-13 - Published: 2014-07-10 - Earliest claimed: 2013-01-07 - Assignees: United States as Represented by the Secretary of the Army; The UAB Research Foundation - Applicants: The Uab Research Foundation - Inventors: Eugenia P. Kharlampieva; Veronika Koziovskaya; Yun Wang; Donald Cropek; Imee Arcibal - Web page: https://patentgrep.com/patent/US20140193651A1 ## CPC - C08F 226/06: by a heterocyclic ring containing nitrogen - B05D 7/52: {Two layers} - B05D 7/56: {Three layers or more} - C09D 5/00: Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced {(electrically insulating plastics, resins or waxes H01B3/30)}; Filling pastes - B05D 1/005: {Spin coating} - B05D 1/185: {applying monomolecular layers (B05D1/204 takes precedence)} - B05D 3/107: {Post-treatment of applied coatings} - B05D 5/00: Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures - B05D 5/04: to obtain a surface receptive to ink or other liquid (B05D5/02, {B41M5/52} take precedence) - B05D 5/08: to obtain an anti-friction or anti-adhesive surface (rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30) - B05D 7/50: {Multilayers} - Y10T 428/31859: Next to an aldehyde or ketone condensation product - Y10T 428/31909: Next to second addition polymer from unsaturated monomers - Y10T 428/31928: Ester, halide or nitrile of addition polymer - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A novel type of ultrathin cationic hydrogel coatings are provided that have high, quick and reversible swelling/shrinkage transitions and surface wettability in response to pH changes. The poly(4-vinyl pyridine) (PVP) hydrogel films are produced by selective cross-linking of PVP copolymers in layer-by-layer (LbL) films assembled by spin-assisted method. These multilayer hydrogels exhibit drastic and reversible 10-fold swelling when the pH is changed from neutral to acidic. The swelling amplitude of these coatings is controlled by varying cross-link densities within the films. The pH-responsive hydrogels open new prospects for developing “intelligent” materials with sharp stimuli-triggered responses for applications in sensing, transport regulation, and self-cleaning coatings. ## Claims ### Claim 1 A pH-responsive layered composition comprising at least two spin-assisted layer-by-layer spun copolymer layers, wherein the spun layers have a plurality of cross-linkable side-groups attached thereto, and wherein the spun layered composition when hydrated swells when protonated and has a reduced volume when deprotonated. ### Claim 2 (depends on 1) The pH-responsive layered composition of claim 1, wherein the at least two spin-assisted layer-by-layer spun copolymer layers are cross-linked. ### Claim 3 (depends on 1) The pH-responsive layered composition of claim 1, wherein the at least two spun copolymer layers are comprised of a polyvinylpyridine copolymer. ### Claim 4 (depends on 1) The pH-responsive layered composition of claim 1, wherein the at least two copolymer spun layers consist essentially of copolymers (PVP-NH2-m) of poly(4-vinylpyridine-NH2-1), poly(4-vinylpyridine-NH2-4), or poly(4-vinylpyridine-NH2-7). ### Claim 5 (depends on 2) The pH-responsive layered composition of claim 2, wherein the at least two copolymer spun layers are separated by alternating spun copolymer layers comprising a copolymer comprising poly(methacrylic acid). ### Claim 6 (depends on 1) The pH-responsive layered composition of claim 1, wherein the cross-linkable side-groups are carboxylate groups, cationic amino groups, or a combination thereof. ### Claim 7 (depends on 6) The pH-responsive layered composition of claim 6, wherein the cross-linkable side-groups are cationic amino groups. ### Claim 8 (depends on 1) The pH-responsive layered composition of claim 1, wherein the copolymer spun layers are cross-linked with glutaraldehyde. ### Claim 9 (depends on 1) The pH-responsive layered composition of claim 1, comprising from 2 to about 50 spun layers, wherein each of the spun layers comprises a poly(vinylpyridine-NH2) copolymer or alternates with a spun layer comprising a poly(methacrylic acid) copolymer. ### Claim 10 A pH-responsive spin-assisted layer-by-layer layered composition comprising at least two glutaraldehyde cross-linked spun layers of a copolymer comprising 4-vinylpyridine and having a plurality of amino side-groups attached thereto, and wherein the spun layered composition when hydrated swells when protonated and has a reduced volume when deprotonated. ### Claim 11 (depends on 10) The pH-responsive layered composition according to claim 10, comprising spun layers of a copolymer consisting essentially of 4-vinylpyridine, and wherein the layered composition is substantially dehydrated. ### Claim 12 A method of forming a pH-responsive composition, the method comprising the steps of: (a) generating a polyvinylpyridine copolymer having a plurality of cross-linkable side-groups attached thereto; (b) generating a layer-by-layer composition by spin-assisted deposition of the polyvinylpyridine copolymer on a support material; and (c) cross-linking the spun layers of the layer-by-layer composition, thereby generating a pH-responsive spin-assisted layer-by-layer layered composition comprising at least two cross-linked spun polyvinylpyridine copolymer layers, wherein the spun-layered composition when hydrated reversible swells when protonated. ### Claim 13 (depends on 12) The method according to claim 12, further comprising the steps of: generating a poly(methacrylic acid) copolymer; spin-assisted deposing the poly(methacrylic acid) copolymer on each of the polyvinylpyridine copolymer layers; cross-linking the polyvinylpyridine copolymer layers; and removing poly(methacrylic acid) copolymer layers under acid conditions. ### Claim 14 (depends on 12) The method according to claim 12, wherein the support material is a silicon surface, and wherein the support material is coated with an agent enhancing the attachment of a copolymer layer to the silicon surface. ### Claim 15 (depends on 14) The method according to claim 14, wherein the agent coating the silicon surface is poly(glycidylmethacrylate). ### Claim 16 (depends on 12) The method according to claim 12, wherein the pH-responsive spin-assisted layer-by-layer layered composition consists essentially of cross-linked layers of a poly(vinylpyridine-NH2). ### Claim 17 (depends on 12) The method according to claim 12, further comprising the step of drying the spin-assisted layer-by-layer layered composition. ### Claim 18 (depends on 12) The method according to claim 12, further comprising the step of displacing the composition from the support material.