Ultra-stable aqueous foams containing highly hydrophobic particles and hydrophilic polymers and their derivated functional materials

Patent metadata

Field	Value
Publication number	US-2021108044-A1
Application number	US-202017026896-A
Country	US
Kind code	A1
Filing date	Sep 21, 2020
Priority date	Oct 9, 2019
Publication date	Apr 15, 2021
Grant date	—

Abstract

Ultra-stable aqueous foam comprises hydrophobic silica particles residing within bubbles in an aqueous solution of a hydrophilic polymer, a protein, or aqueous dispersible colloidal particles. The combination of the hydrophobic and hydrophilic components stabilizes the foam interfaces to result in long term stability of the foam. The foams can be crosslinked to stable monolithic foams and used for structural foams, coatings, and thermal insulating for construction.

First claim

We claim:

1 . An ultra-stable aqueous foam, comprising one or more hydrophobic particles residing within bubbles in an aqueous solution of one or more hydrophilic polymers, one or more proteins, or one or more aqueous dispersible colloidal particles.

2 . The ultra-stable aqueous foam according to claim 1 , wherein the ratio of the hydrophobic particles to the hydrophilic polymer, the protein, or the aqueous dispersible colloidal particles is 3:4 to 20:1 and wherein the concentration of the hydrophilic polymer, the protein, or the aqueous dispersible colloidal particles is 0.1 to 10 wt. %.

3 . The ultra-stable aqueous foam according to claim 1 , wherein the hydrophobic particles are polydimethylsiloxane functionalized silica, perfluorinated alkyl functionalized silica, or alkylated silica particles, and the hydrophobic polymeric particles are PTFE or PVDF particles.

4 . The ultra-stable aqueous foam according to claim 1 , wherein the hydrophilic polymer is polyvinyl alcohol (PVA), poly(ethyleneglycol) (PEG), polyvinylpyrrolidone (PVP), or methyl cellulose.

5 . The ultra-stable aqueous foam according to claim 1 , wherein the protein is bovine serum albumin (BSA).

6 . The ultra-stable aqueous foam according to claim 1 , wherein the aqueous dispersible colloidal particles are poly(N-isopropyl acrylamide) (PNIPAM)-based microgels or cross-linked zein protein.

7 . The ultra-stable aqueous foam according to claim 1 , further comprising a cross-linker.

8 . The ultra-stable aqueous foam according to claim 7 , wherein the cross-linker is glutaraldehyde.

9 . The ultra-stable aqueous foam according to claim 1 , further comprising a multiplicity of second particles or small molecular additives.

10 . The ultra-stable aqueous foam according to claim 1 , where the second particles are hydrophilic silica particle or ethyl cellulose powder, and the small molecular additives are inorganic salts or melamine.

11 . A porous monolith, comprising the ultra-stable aqueous foam according to claim 1 , the ultra-stable aqueous foam is crosslinked.

12 . A method of preparing the ultra-stable aqueous foam according to claim 1 , comprising:
providing an aqueous solution of a hydrophilic polymer or a protein; or providing an aqueous dispersion of aqueous dispersible colloidal particles; providing a multiplicity of hydrophobic particles; adding the hydrophobic silica particles to the solution or the aqueous dispersion to form a mixture; and agitating the mixture to form the ultra-stable aqueous foam.

13 . The method according to claim 12 , wherein the hydrophilic polymer, the protein, or the aqueous dispersible colloidal particles is at 0.1 to 10 wt. %.

14 . The method according to claim 12 , wherein the hydrophilic polymer is polyvinyl alcohol (PVA), poly(ethyleneglycol) (PEG), polyvinylpyrrolidone (PVP), or methyl cellulose.

15 . The method according to claim 12 , wherein the protein is bovine serum albumin (BSA).

16 . The method according to claim 12 , wherein the aqueous dispersible colloidal particles are poly(N-isopropyl acrylamide) (PNIPAM)-based microgels or cross-linked zein protein.

17 . The method according to claim 12 , wherein the hydrophobic silica particles are polydimethylsiloxane, or perfluorinated alkyl functionalized silica particles, or alkylated silica particles.

18 . The method according to claim 12 , wherein agitating is shaking, stirring, homogenizing, or high shear mixing.

Assignees

• Univ Hong Kong Chinese

Inventors

• Ngai To
• Sheng Yifeng
• Lin Kuan Ting

Classifications

• C08K9/06

  with silicon-containing compounds · CPC title

• C08K2201/011

  Nanostructured additives · CPC title

• C08K3/36

  Silica · CPC title

• A62D1/0071

  Foams · CPC title

• C08J9/30 Primary

  by mixing gases into liquid compositions or plastisols, e.g. frothing with air · CPC title