Polymer composite with liquid phase metal inclusions
Disclosed herein is a composite comprising an elastomer with an embedded network of liquid metal inclusions. The composite retains similar flexibility to that of an elastomer but exhibits electrical and thermal properties that differ from the properties of a homogeneous elastomer. The composite has applications for wearable devices and other soft matter electronics, among others.
1. A composite consisting of:
an elastic polymer, and
a liquid metal,
wherein the liquid metal is embedded within the elastic polymer to form a network of inclusions,
wherein each inclusion of the network of inclusions has a diameter of about 2-30 μm,
wherein the liquid metal has a melting point within the range of −19 degrees Celsius to 15 degrees Celsius,
wherein the composite has a strain limit of at least 100%.
2. The composite of claim 1 , wherein the elastic polymer is selected from the group consisting of polysiloxane, polydimethylsiloxane, silicone, polyurethane, polyacrylate, natural latex rubber, block copolymer elastomers, styrene ethylene butylene styrene, thermoplastic elastomers, and propylene-ethylene co-polymer.
3. The composite of claim 1 , wherein the liquid metal is selected from the group consisting of eutectic gallium indium and gallium-indium tin.
4. The composite of claim 1 , wherein the liquid metal is a eutectic alloy.
5. The composite of claim 1 , wherein a conductive channel consists of an interconnected series of ruptured inclusions.
6. The composite of claim 5 , wherein the conductive channel has a conductivity of about 1.05×10∧4 S/m.
7. The composite of claim 1 , wherein the network of inclusions is not conductive.
8. The composite of claim 1 , wherein each inclusion of the network of inclusions are separated by at least a portion of the elastic polymer.
9. The composite of claim 1 , wherein a volume loading of the liquid metal is about 10-50%.
10. The composite of claim 1 , wherein the composite has a thermal conductivity of about 9.8 W/m*K at 400% strain.
11. The composite of claim 1 , wherein the inclusions are elongated in a pre-strained direction.
12. A composite consisting of:
an elastic polymer, and
a liquid metal,
wherein the liquid metal is embedded within the elastic polymer to form a non-conductive network of inclusions,
wherein each inclusion of the network of inclusions has a diameter of about 2-30 μm,
wherein the liquid metal is selected from the group consisting of gallium and gallium-based alloys,
wherein the composite has a strain limit of at least 100%.
13. A method of fabricating the composite of claim 1 , comprising:
combining the elastic polymer with the liquid metal,
wherein the volume ratio of the elastic polymer to the liquid metal is 1:1;
mixing the elastic polymer and liquid metal until the liquid metal forms droplets suspending in the elastic polymer; and
curing the elastic polymer.
14. The method of claim 13 , further comprising:
mixing the elastic polymer and liquid metal until the droplets have a diameter of about 2-30 μm.
15. The method of claim 13 , wherein mixing the elastic polymer and liquid metal comprises shear mixing the elastic polymer and liquid metal using a mortar and pestle.
16. The method of claim 13 , wherein mixing the elastic polymer and liquid metal comprises mixing the elastic polymer and liquid metal using sonication.
17. The method of claim 13 , further comprising:
creating a pattern in the composite.
18. The method of claim 17 , wherein the pattern is created by at least one of 3D printing, soft lithography, laser ablation, and stencil lithography.