Switchable liquid repellent and active water harvesting surface

Patent metadata

Field	Value
Publication number	US-10730789-B2
Application number	US-201715831930-A
Country	US
Kind code	B2
Filing date	Dec 5, 2017
Priority date	Dec 5, 2016
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

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 micropillars, each of the micropillars including a flexible polymer and a magnetically responsive particle; and
a lubricant layer conformally infused onto the micropillars,
wherein the micropillars have a first orientation predominately upright relative to the surface corresponding to a superhydrophobic state of the switchable surface and a second orientation angled relative to the first orientation corresponding to a slippery state of the switchable surface.

2. The substrate according to claim 1 , wherein the magnetically responsive micropillars are hierarchical micropillars having self-assembling nanoparticles forming a textured surface on the micropillars.

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

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

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

6. A method of switching a surface character of a substrate with a switchable surface, the method comprising the step of:
providing a substrate with a switchable surface, including:
an array of magnetically responsive micropillars, each of the micropillars including a flexible polymer and a magnetically responsive particle; and
a lubricant layer conformally infused onto the micropillars,
wherein the array of micropillars has a first orientation predominately upright relative to the surface corresponding to a superhydrophobic state of the switchable surface and a second orientation angled relative to the first orientation corresponding to a slippery state of the switchable surface; and

applying an external magnetic field to the substrate, thereby changing the orientation of the array between the first and second orientations and causing the switching of the surface between the superhydrophobic and slippery states.

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

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

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

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

11. The method according to claim 6 , further comprising the step of restoring the superhydrophobic state by first switching the surface to the slippery state to remove pinned water droplets.

Assignees

• Penn State Res Found

Inventors

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

Classifications

• C03C17/42 Primary

  at least one coating of an organic material and at least one non-metal coating · CPC title

• C09D5/1675

  Polyorganosiloxane-containing compositions · CPC title

• C03C2217/48

  having a specific function · CPC title

• C09D5/1681

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

• C03C2218/322

  Oxidation · CPC title