Aqueous composition and a method of producing durable and extremely efficient water repelling superhydrophobic materials at ambient condition thereof

Patent metadata

Field	Value
Publication number	US-11242468-B2
Application number	US-201816163325-A
Country	US
Kind code	B2
Filing date	Oct 17, 2018
Priority date	Oct 17, 2017
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

The present invention relates to adurable and multifunctional superhydrophobic coating composition and water based fabrication method of producing the durable and multifunctional superhydrophobic coating composition via chemical modification and functionalization of hydrophilic material by silanes under room temperature without any organic solvents. Synthesis of chemically modified cellulose nanofibers or clay in water forms excellent water repelling thin films upon coating over various substrates. The super hydrophobic materials are used as additive for paints, pigments, paper, varnish and, textile and used for various industrial applications such as construction of buildings and other super structures.

First claim

We claim:

1. A superhydrophobic coating composition, said composition comprising hydrophilic material selected from cellulose nanofibers and clays in the range of 0.25 wt %-2.06 wt % and one or more silanes in the range of 0.24 wt %-2.05 wt %, and the remaining being water in the range of 97.7 wt %-99.51 wt %, wherein said hydrophilic material is chemically modified and functionalized using said silanes in aqueous medium and free of any organic solvent.

2. The coating composition as claimed in claim 1 , wherein clays include kaolinite clays.

3. The coating composition as claimed in claim 1 , wherein the silanes include amino silane, fluorosilane and alkyl silane.

4. The coating composition as claimed in claim 3 , wherein the amino silane includes 3-(2-aminoethylamino) propyltrimethoxysilane, the fluorosilane includes 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane and the alkyl silane includes n-octadecylsilane.

5. The coating composition as claimed in claim 3 , wherein the amino silane is used to develop transparent water repellent coating with fluorosilanes, unsaturated molecules including monomeric, polymeric, polar and nonpolar acrylates depending on their solubility and dispersibility in different solvents.

6. A superhydrophobic cellulose nanofiber coating material, comprising a composition including, 0.25 wt % of hydrophilic cellulose nanofiber (CNF), 0.61 wt % of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 0.92 wt % of 3-(2-aminoethylamino) propyltrimethoxysilane and the remaining 98.22 wt % being water, wherein said cellulose nanofiber is chemically modified and functionalized using said silanes in aqueous medium,
wherein when applied to a substrate, the superhydrophobic cellulose nanofiber coating material provides a water contact angle greater than 160°.

7. A superhydrophobic kaolinite clay coating material, comprising a composition including, 1.47 wt % of hydrophilic kaolinite clay, 0.24 wt % of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane/0.36 wt % n-octadecylsilane, 0.49 wt % of 3-(2-aminoethylamino) propyltrimethoxysilane and the remaining 97.68 wt %-97.8 wt % being water, wherein said kaolinite clay is chemically modified and functionalized using said silanes in aqueous medium,
wherein when applied to a substrate, the superhydrophobic coating composition provides a water contact angle greater than 170°.

8. A substrate coated with the composition as claimed in claim 1 , said substrate resists mechanical abrasion.

9. A substrate coated with the composition as claimed in claim 1 , said substrate exhibits thermal stability in the range of −50° C. to 200° C. based on contact angle measurement of ethanol, tetrahydrofuran (THF), dimethylformamide (DMF), toluene and hexane.

10. A substrate coated with the composition as claimed in claim 1 , said substrate exhibits antibacterial and antifungal properties.

11. The coating composition as claimed in claim 1 , wherein when applied to a substrate, the superhydrophobic coating composition adsorbs moisture and CO 2 from air at room temperature.

Assignees

• Indian Institute Of Tech Madras
• Indian Institute Of Tech Madras Itt Madras

Inventors

• Thalappil Pradeep
• Baidya Avijit
• Ganayee Mohd Azhardin
• Jakka Ravindran Swathy

Classifications

• C08B15/05 Primary

  Derivatives containing elements other than carbon, hydrogen, oxygen, halogens or sulfur (esters or phosphorous acids C08B5/00) · CPC title

• C08B15/06

  containing nitrogen {, e.g. carbamates} · CPC title

• C09D5/1681

  Antifouling coatings characterised by surface structure, e.g. for roughness effect giving superhydrophobic coatings or Lotus effect · CPC title

• C09D101/08

  Cellulose derivatives · CPC title

• C08K9/06

  with silicon-containing compounds · CPC title