Stretchable thermal radiation modulation system via mechanically tunable surface emissivity

1. A thermal radiation modulation system, comprising:

a low emissivity layer comprising a plurality of distributed, strain-dependent cracks, the low emissivity layer comprising a polymer composite layer and a mirror-like metal layer with low emissivity covering a surface of the polymer composite layer;

an elastomer layer bonded to the low emissivity layer opposite to the mirror-like metal layer; and

optionally a stretchable heater, the stretchable heater is attached to the elastomer layer opposite to the low emissivity layer,

wherein a top surface of the low emissivity layer comprising the mirror-like metal layer has a lower emissivity relative to the elastomer layer.

2. The thermal radiation modulation system of claim 1 , comprising the stretchable heater.

3. The thermal radiation modulation system of claim 1 , further comprising an adhesive layer, an additional polymer composite layer, an additional low emissivity mirror-like metal layer, an additional elastomer layer, or a combination thereof.

4. The thermal radiation modulation system of claim 1 , wherein the polymer composite layer comprises a polymer and an inorganic material.

5. The thermal radiation modulation system of claim 4 , wherein the polymer composite layer comprises a 5:0.5 to 1:20 mass ratio of inorganic material:polymer.

6. The thermal radiation modulation system of claim 4 , wherein the polymer is polyvinylalcohol, polyvinyl butyral, polycarbonate, a polyacrylate, poly(ethyl acrylate), poly(methyl acrylate), poly(methyl methacrylate), polystyrene sulfonate, polyacrylic acid, polyethylenimine, polypropylene carbonate, polyvinylpyrrolidone, any non-crosslinked polymer, or a combination thereof.

7. The thermal radiation modulation system of claim 4 , wherein the polymer is polyvinylalcohol.

8. The thermal radiation modulation system of claim 4 , wherein the inorganic material is titanium dioxide; laponite; aluminum oxide; magnesium oxide; zinc oxide; silicon oxide; Palygorskite (attapulgite); iron oxide; calcium oxide; copper oxide; tungsten oxide; montmorillonite; halloysite; kaolinite; Au; Pd; Ag; Al; or a combination thereof.

9. The thermal radiation modulation system of claim 1 , wherein the elastomer layer comprises polyurethane rubber, polyacrylate rubber, acrylic rubber, natural rubber, fluoroelastomer, ethylene-propylene rubber (EPR), ethylene-butene rubber, ethylene-propylene-diene monomer rubber (EPDM), epichlorohydrin rubber, acrylate rubbers, hydrogenated nitrile rubber (HNBR), silicone elastomers, polyether block amides, ethylene vinyl acetate, styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), styrene-(ethylene-butene)-styrene (SEBS), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-ethylene-propylene-diene-styrene (AES), styrene-isoprene-styrene (SIS), styrene-(ethylene-propylene)-styrene (SEPS), methyl methacrylate-butadiene-styrene (MBS), high rubber graft (HRG), polydimethylsiloxane (PDMS), or a combination thereof.

10. The thermal radiation modulation system of claim 1 , wherein the elastomer layer comprises a silicone elastomer.

11. The thermal radiation modulation system of claim 1 , wherein

the elastomer layer has a thickness of about 0.05 to about 5 millimeters thick;

the low emissivity layer has a thickness of about 10 nanometers to 350 micrometer; and

the polymer composite layer has a thickness of about 5 nanometer to about 300 micrometer; and

the mirror-like metal layer has a thickness of about 1 nanometers to about 5 micrometer.

12. The thermal radiation modulation system of claim 1 , wherein the thermal radiation modulation system can be used with an external heat source.

13. An article comprising the thermal radiation modulation system of claim 1 , wherein the article is a motion detection device, a thermal encryption device, a dynamic display, or thermal camouflage.

14. A method of using a thermal radiation modulation system, comprising:

providing a thermal radiation modulation system of claim 1 ;

applying a tensile strain of greater than 0% to less than 200% to the system, wherein the thermal radiation modulation system undergoes a reversible and tunable change in surface thermal radiation level.

15. The method of claim 14 , wherein the application of a strain is conducted in-plane uniaxial strain or out-of-plane bulging strain.

16. A method of making a thermal radiation modulation system, comprising:

providing a polymer composite layer on a substrate, the polymer composite layer comprising a polymer and an inorganic material;

applying a layer of elastomer on a top surface of the polymer composite layer and curing the elastomer to form a composite-elastomer assembly on the substrate;

removing the composite-elastomer assembly from the substrate;

applying a mirror-like metal layer on a surface of first polymer composite layer opposite to the elastomer layer;

optionally attaching a stretchable heater to a surface of the elastomer layer opposite to the polymer composite layer; and

forming a plurality of cracks in the polymer composite layer and mirror-like metal layer to result in a thermal radiation modulation system,

wherein the mirror-like metal layer exhibits low emissivity relative to the elastomer layer.

17. The method of claim 16 , wherein the forming a plurality of cracks comprises pre-stretching the composite-elastomer assembly under strain and releasing the stretch to 0% strain.

18. The method of claim 17 , wherein the pre-stretching is conducted with in-plane uniaxial strain, in-plane biaxial strain, or a two-step in-plane uniaxial strain where the axes are perpendicular to one another.

19. The method of claim 17 , wherein the pre-stretching comprises applying a 50% to 250% uniaxial tensile pre-stretch to the composite-elastomer assembly; and

releasing the pre-stretch to 0% strain.