Electroactive polymer manufacturing

Abstract

Described herein are transducers and their fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

1 . A method of fabricating a device comprising an electroactive polymer and multiple electrodes, the method comprising:
 mechanically stretching a polymer to form a pre-strained electroactive polymer, wherein the pre-strained electroactive polymer has an elastic modulus below 100 MPa;   fixing a first portion of the pre-strained electroactive polymer to a solid member;   forming a first electrode on a portion of a first surface of the pre-strained electroactive polymer; and   forming a second electrode on a portion of a second surface of the pre-strained electroactive polymer.   
     
     
         2 . The method of  claim 1  wherein the pre-strained electroactive polymer is elastically pre-strained. 
     
     
         3 . The method of  claim 1  wherein the polymer is one of: a silicone elastomer, PVDF copolymer, or adhesive elastomer. 
     
     
         4 . The method of  claim 1  wherein the first portion of the pre-strained electroactive polymer includes an edge portion of the electroactive polymer. 
     
     
         5 . The method of  claim 1  wherein the pre-strain is applied uniformly over a second portion of the polymer to produce an isotropic pre-strained electroactive polymer. 
     
     
         6 . The method of  claim 1  wherein the pre-strain is applied unequally in different directions for a second portion of the polymer to produce an anisotropic pre-strained electroactive polymer. 
     
     
         7 . The method of  claim 1  wherein the pre-strain includes a strain between about 100 and about 500 percent in each planar direction. 
     
     
         8 . The method of  claim 1  wherein forming first electrode comprises spraying an electrode solution onto the pre-strained polymer using a mask that defines the portion of the first surface. 
     
     
         9 . The method of  claim 1  wherein the electrode solution includes carbon black, a binder and a solvent. 
     
     
         10 . The method of  claim 1  wherein fixing the portion of the pre-strained electroactive polymer to the solid member includes attaching the solid member to the portion using an adhesive. 
     
     
         11 . The method of  claim 1  wherein the solid member includes one of: a rigid plastic or metal or a flexible plastic film or metal film. 
     
     
         12 . A method of fabricating a device comprising an electroactive polymer and multiple electrodes, the method comprising:
 mechanically stretching a polymer to form a pre-strained electroactive polymer, wherein the pre-strained electroactive polymer has an elastic modulus below 100 MPa;   fixing a portion of the pre-strained electroactive polymer to a solid member;   spraying an electrode solution onto a first surface of the electroactive polymer using a first mask that defines a pattern for a first electrode on the first surface of the electroactive polymer; and   spraying the electrode solution onto a second surface of the electroactive polymer using a second mask that defines a pattern for a second electrode on the second surface of the electroactive polymer.   
     
     
         13 . The method of  claim 12  wherein the electrode solution includes a conductive grease and a solvent. 
     
     
         14 . The method of  claim 13  further comprising dissolving the conductive grease in the solvent to form the electrode solution. 
     
     
         15 . The method of  claim 13  wherein the electrode solution also includes an uncured conductive silicone or an uncured elastomer. 
     
     
         16 . The method of  claim 12  wherein fixing the portion of the electroactive polymer to the solid member uses an adhesive. 
     
     
         17 . The method of  claim 12  wherein the mechanical stretch includes a strain greater than about 40 percent in a planar direction of the polymer. 
     
     
         18 . The method of  claim 17  wherein the mechanical stretch includes a strain greater than about 100 percent in a planar direction of the polymer. 
     
     
         19 . The method of  claim 12  wherein the electroactive polymer includes an additive. 
     
     
         20 . The method of  claim 19  wherein the additive improves at least one of polymer dielectric breakdown strength, maximum linear strain, dielectric constant, elastic modulus, response time and actuation voltage.