Switchable liquid repellent and active water harvesting surface

Patent metadata

Field	Value
Publication number	US-2018155239-A1
Application number	US-201715831930-A
Country	US
Kind code	A1
Filing date	Dec 5, 2017
Priority date	Dec 5, 2016
Publication date	Jun 7, 2018
Grant date	—

Abstract

A substrate with a switchable surface has been developed that can rapidly switch its surface character such as between two distinct liquid-repellent modes: (1) a superhydrophobic mode and (2) a slippery mode. Such surfaces have demonstrated adaptive liquid repellency and water harvesting capabilities.

First claim

What is claimed:

1 . A substrate with a switchable surface comprising an array of magnetically responsive hierarchical micropillars and a lubricant layer conformally infused thereon wherein each of the micropillars comprise a magnetically responsive particle and a flexible polymer.

2 . The substrate of claim 1 , wherein the magnetically responsive particle is an iron microsphere.

3 . The substrate of claim 1 , wherein the flexible polymer comprises polydimethylsiloxane.

4 . The substrate of claim 1 , wherein the lubricant comprises a perfluorinated oil, a silicone oil, a polydimethylsiloxane, a hydroxy polydimethylsiloxane or any combination thereof.

5 . The substrate of claim 1 , wherein the hierarchical micropillars comprise nanostructures on the micropillars.

6 . A method of switching the surface character of a substrate which includes an array of magnetically responsive hierarchical micropillars and a lubricant layer conformally infused thereon, the method comprising:
changing an orientation of the array with an external magnetic field. Advantageously, changing the orientation of the array results in switching between superhydrophohic and slippery states. This can occur quickly and repeatedly, which allows maintenance of liquid repellency in fast changing dynamic environmental conditions.

7 . The method of claim 6 , comprising orienting the array predominately perpendicular relative to the substrate.

8 . The method of claim 6 , comprising orienting the array predominately parallel relative to the substrate.

9 . The method of claim 6 , comprising repeatedly changing the orientation of the array.

10 . A water harvesting device comprising a substrate of claim 1 .

11 . A process of fabricating a switchable surface comprising an array of magnetically responsive hierarchical micropillars, the method comprising:
applying a compositing including polymer forming ingredients, a curing agent, and magnetically responsive particles onto a substrate; forming micropillars infused with magnetic nanoparticles by curing the composition in the presence of a magnetic field; forming a textured surface on the micropillars; and silanizating the surface of the hierarchal micropillars and applying a lubricate on t e silanized hierarchal micropillars.

Assignees

• Penn State Res Found

Inventors

• Wong Tak-Sing
• Huang Yu
• Boschitsch Birgitt
• Sun Nan

Classifications

• C08K2201/01

  Magnetic additives · CPC title

• C03C17/32

  with synthetic or natural resins (C03C17/30 takes precedence) · CPC title

• C08K3/08

  Metals · CPC title

• C03C2217/76

  Hydrophobic and oleophobic coatings · CPC title

• C03C17/3405 Primary

  with at least two coatings of organic materials (C03C17/36, C03C17/42 take precedence) · CPC title