Fabrication of shaped voids
In some examples, a method includes forming a material layer on a substrate, partially polymerizing a component of the material layer, to form fluid-filled droplets within a partially polymerized matrix, deforming the material layer to form anisotropic fluid-filled droplets, and further polymerizing the partially polymerized matrix to form an anisotropic voided polymer, including anisotropic voids in a polymer matrix. The anisotropic voids may include anisotropic nanovoids. Example methods may further include depositing electrodes on the anisotropic voided polymer so that at least a portion of the anisotropic voided polymer is located between the electrodes. Examples may include forming electroactive elements including an anisotropic nanovoided polymer, and devices (such as sensors and/or actuators) including electroactive elements.
1. A method, comprising:
forming a material layer on a substrate, the material layer comprising fluid-filled voids within a partially polymerized matrix;
deforming the material layer to form anisotropic voids within the partially polymerized matrix; and
polymerizing the material layer to form an anisotropic voided polymer comprising the anisotropic voids within a polymer matrix;
wherein forming the material layer on the substrate comprises:
forming a layer on the substrate, the layer comprising the fluid-filled voids within a medium, the medium comprising a polymerizable component; and
partially polymerizing the polymerizable component to form the material layer.
2. The method of claim 1 , further comprising removing a liquid from the anisotropic voided polymer to produce gas-filled anisotropic voids within the anisotropic voided polymer.
3. The method of claim 1 , wherein deforming the material layer comprises stretching the material layer.
4. The method of claim 1 , wherein deforming the material layer comprises stretching the substrate.
5. The method of claim 4 , wherein stretching the substrate comprises stretching the substrate using one or more rollers.
6. The method of claim 4 , wherein stretching the substrate comprises stretching the substrate in two orthogonal directions.
7. The method of claim 1 , wherein deforming the material layer comprises compressing the material layer along at least one direction.
8. The method of claim 1 , wherein deforming the material layer comprises applying an electric field or magnetic field to the material layer.
9. The method of claim 1 , wherein deforming the material layer comprises removing a fluid component from the fluid-filled voids,
wherein removing the fluid component from the fluid-filled voids induces a partial collapse of the fluid-filled voids.
10. The method of claim 1 , further comprising removing the anisotropic voided polymer from the substrate.
11. The method of claim 1 , further comprising depositing electrodes on the anisotropic voided polymer so that at least a portion of the anisotropic voided polymer is located between the electrodes.
12. The method of claim 1 , further comprising forming an electroactive device using the anisotropic voided polymer,
wherein the electroactive device is a sensor or an actuator.
13. The method of claim 1 , wherein the polymer matrix is an electroactive polymer matrix.
14. The method of claim 1 , wherein the polymer matrix comprises at least one of a silicone polymer, or an acrylate polymer.
15. The method of claim 1 , wherein the partially polymerized matrix comprises at least one polymer having a degree of polymerization between 20% and 80%.
16. The method of claim 1 , wherein the partially polymerized matrix comprises at least one polymer having a degree of polymerization between 30% and 70%.