Stimuli-responsive polymer composites

Patent metadata

Field	Value
Publication number	US-10072129-B2
Application number	US-201414766612-A
Country	US
Kind code	B2
Filing date	Feb 7, 2014
Priority date	Feb 8, 2013
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A polymer composite is provided that includes a plurality of heat-absorbing nanomaterials, a plurality of thermally-expanding microspheres, and an elastomeric matrix. In the polymer composite, the heat-absorbing nanomaterials and the thermally-expanding microspheres are dispersed within the elastomeric matrix such that the thermally-expanding microspheres expand and stretch the matrix upon exposure to a thermal stimulus. Methods of forming a thermally-expanding polymer composite are also provided and include the steps of dispersing a plurality of heat-absorbing nanomaterials in an evaporative solvent; combining the dispersion with an amount of an elastomeric material to create a mixture; adding an amount of thermally-expanding microspheres to the mixture; and polymerizing the mixture. Circuits including resistors comprised of the polymer composites are further provided.

First claim

What is claimed is:

1. A circuit, comprising a resistor including a plurality of carbon nanotubes, a plurality of thermally-expanding microspheres comprised of an acrylic copolymer shell encapsulating a liquid isobutane core, and an elastomeric matrix, the heat-absorbing nanomaterials and the thermally-expanding microspheres dispersed within the elastomeric matrix such that the thermally-expanding microspheres expand and stretch the matrix upon exposure to a thermal stimulus sufficient to raise the temperature of the thermally-expanding microspheres to about 100° C. to about 200° C. and for an amount of time sufficient to vaporize the liquid isobutane core.

2. The circuit of claim 1 , wherein the resistor comprises a first resistor and a second resistor, the first resistor including a greater weight percentage of heat-absorbing nanomaterials than the second resistor.

3. The circuit of claim 1 , wherein the carbon nanotubes are single-walled carbon nanotubes.

4. The circuit of claim 1 , wherein the acrylic copolymer shell comprises poly(vinylidene chloride-co-acrylonitrile-co-methyl methacrylate).

5. The circuit of claim 1 , wherein the thermally-expanding microspheres have a diameter of about 5 μm to about 10 μm prior to exposure to the thermal stimulus and a diameter of about 10 μm to about 20 μm subsequent to exposure to the thermal stimulus.

6. The circuit of claim 1 , wherein the elastomeric matrix is comprised of polydimethylsiloxane.

Assignees

• Univ Louisville Res Found Inc

Inventors

• Loomis James
• Panchapakesan Balaji

Classifications

• H05K1/0283

  Stretchable printed circuits · CPC title

• H05K1/028

  Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence) · CPC title

• C08J2333/20

  Homopolymers or copolymers of acrylonitrile (C08J2355/02 takes precedence) · CPC title

• C08K9/10

  Encapsulated ingredients · CPC title

• C08K7/24

  inorganic · CPC title