Composite membranes and methods of making and use thereof

Patent metadata

Field	Value
Publication number	US-2018345227-A1
Application number	US-201815995677-A
Country	US
Kind code	A1
Filing date	Jun 1, 2018
Priority date	Jun 1, 2017
Publication date	Dec 6, 2018
Grant date	—

Abstract

Disclosed herein are composite membranes comprising an omniphobic substrate having a reentrant structure. The omniphobic substrate comprises a plurality of pores, the plurality of pores forming the reentrant structure. The omniphobic substrate further comprises a surface, the surface being coated with a dual functional layer that is hydrophilic in air and oleophobic under water, such that the composite membrane has a top portion and a bottom portion, the top portion comprising the coated surface of the omniphobic substrate, such that the top portion of the composite membrane is hydrophilic in air and oleophobic under water and the bottom portion of the composite membrane is omniphobic. The composite membrane can be antiwetting and/or antifouling in the presence of a hydrophobic contaminant, an amphiphilic contaminant, or a combination thereof. The composite membranes can be used for membrane distillation of a contaminated brine solution.

First claim

What is claimed is:

1 . A composite membrane comprising
an omniphobic substrate having a reentrant structure, wherein
the omniphobic substrate comprises a plurality of pores, the plurality of pores forming the reentrant structure; and
the omniphobic substrate has a surface, the surface being coated with a dual functional layer that is hydrophilic in air and oleophobic under water,
such that:
the composite membrane has a top portion and a bottom portion, the top portion comprising the coated surface of the omniphobic substrate,
such that:
the top portion of the composite membrane is hydrophilic in air and oleophobic under water, and
the bottom portion of the composite membrane is omniphobic.

2 . The composite membrane of claim 1 , wherein the omniphobic substrate comprises a plurality of polymer fibers.

3 . The composite membrane of claim 2 , wherein the plurality of polymer fibers comprise a hydrophobic polymer.

4 . The composite membrane of claim 2 , wherein the plurality of polymer fibers comprise polypropylene, poly(vinylidene fluoride-co-hexafluoropropylene), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, or a combination thereof.

5 . The composite membrane of claim 1 , wherein the reentrant structure of the omniphobic substrate comprises a hierarchical reentrant structure.

6 . The composite membrane of claim 5 , wherein the omniphobic substrate comprises a plurality of polymer fibers coated with a plurality of particles having an average particle size of from 10 nm to 1000 nm.

7 . The composite membrane of claim 6 , wherein the plurality of particles comprise a plurality of polystyrene particles, a plurality of silicon dioxide particles, a plurality of titanium dioxide particles, a plurality of ceramic particles, or a combination thereof.

8 . The composite membrane of claim 6 , wherein the plurality of particles further comprise a low surface energy material comprising a fluoroalkylsilane.

9 . The composite membrane of claim 6 , wherein the plurality of polymer fibers have a first surface charge and the plurality of particles have a second surface charge, such that the plurality of particles are attached to the plurality of fibers by electrostatic attraction between the first surface charge and the second surface charge.

10 . The composite membrane of claim 1 , wherein the dual functional layer comprises a surface roughness component and a hydrophilic component.

11 . The composite membrane of claim 10 , wherein the surface roughness component comprises a plurality of particles having an average particle size of from 10 nm to 1000 nm and wherein the plurality of particles comprise a plurality of polystyrene particles, a plurality of silicon dioxide particles, a plurality of titanium dioxide particles, a plurality of ceramic particles, or a combination thereof.

12 . The composite membrane of claim 10 , wherein the hydrophilic component comprises a hydrophilic polymer.

13 . The composite membrane of claim 10 , wherein the hydrophilic component comprises chitosan, cellulose, derivatives thereof, or combinations thereof.

14 . The composite membrane of claim 10 , wherein the dual functional layer further comprises a low surface energy material comprising a fluorinated compound.

15 . A method of making the composite membrane of claim 1 , the method comprising depositing the dual functional layer on the surface of the omniphobic substrate.

16 . The method of claim 15 , further comprising forming the omniphobic substrate.

17 . The method of claim 15 , wherein the omniphobic substrate comprises a plurality of polymer fibers and the omniphobic substrate is formed by electrospinning.

18 . A method of use of the composite membrane of claim 1 for membrane distillation of a contaminated brine solution, wherein the contaminated brine solution comprises a hydrophobic contaminant, an amphiphilic contaminant, or a combination thereof.

19 . The method of claim 18 , wherein the composite membrane is antiwetting and antifouling.

20 . The method of claim 18 , wherein the composite membrane exhibits a salt rejection of 99% or more over the course of the distillation.

Assignees

• Univ Vanderbilt

Inventors

• Lin Shihong
• Wang Zhangxin
• Huang Yu-Xi

Classifications

• B01D2325/02

  Details relating to pores or porosity of the membranes · CPC title

• B01D2323/04

  Hydrophobization · CPC title

• B01D2325/26

  Electrical properties · CPC title

• B01D2325/40

  Fibre reinforced membranes · CPC title

• B01D69/12 Primary

  Composite membranes; Ultra-thin membranes · CPC title