Rolled electroactive polymers

Abstract

The invention describes electroactive polymer devices in both rolled and unrolled configurations. The invention also describes employment of these devices in a wide array of applications and methods for their fabrication. An electroactive polymer device converts between electrical and mechanical energy; and, in one embodiment includes a rolled electroactive polymer and one or more electrodes to provide the mechanical/electrical energy conversion. In one embodiment, the electroactive polymer has a non-uniform surface on which an electrode having a non-uniform shape is disposed.

1 . An electroactive polymer transducer comprising:
 an electroactive polymer having an elastic modulus below 100 Mpa, the electroactive polymer having a non-uniform first surface; and   a first electrode having a non-uniform shape conformably disposed on the first surface of the electroactive polymer.   
     
     
         2 . The electroactive polymer transducer of  claim 1 , wherein the first surface of the electroactive polymer comprises a series of troughs and crests, and the non-uniform shape of first electrode comprises a series of troughs and crests. 
     
     
         3 . The electroactive polymer transducer of  claim 2 , wherein the troughs and crests of the electrode substantially conform to the troughs and crests on the first surface of the electroactive polymer. 
     
     
         4 . The electroactive polymer transducer of  claim 2 , wherein the electroactive polymer has a non-uniform second surface, and the electroactive polymer transducer further comprises a second electrode having a non-uniform shape conformably disposed on the second surface of the electroactive polymer. 
     
     
         5 . The electroactive polymer transducer of  claim 2 , wherein the troughs and crests of the first surface decrease in depth and height respectively when the electroactive polymer transducer is actuated, such that the first electrode strains less than the electroactive polymer when the electroactive polymer transducer is actuated. 
     
     
         6 . The electroactive polymer transducer of  claim 4 , wherein the first surface is opposite to the second surface, and the electroactive polymer actuates linearly when a voltage is applied across the first and second electrodes such that the troughs and crests of the first and second surfaces decrease in depth and height respectively and increase in length. 
     
     
         7 . The electroactive polymer transducer of  claim 2 , wherein troughs and crests of the first surface align perpendicularly to a direction of actuation of the transducer. 
     
     
         8 . A polymer roll transducer comprising:
 an electroactive polymer roll having a plurality of layers of an electroactive polymer having an elastic modulus below 100 Mpa in a rolled configuration, wherein the electroactive polymer has an electrode having a non-uniform shape disposed thereon.   
     
     
         9 . The transducer of  claim 8 , further comprising an end cap to secure the electroactive polymer roll in its rolled configuration. 
     
     
         10 . The transducer of  claim 8 , wherein the non-uniform shape of the electrode comprises a textured shape. 
     
     
         11 . The transducer of  claim 8 , wherein the non-uniform shape of the electrode comprises troughs having a width and a depth substantially less than a thickness of the electroactive polymer. 
     
     
         12 . The transducer of  claim 8 , wherein the non-uniform shape of the electrode comprises crests having a width and a height substantially less than a thickness of the polymer. 
     
     
         13 . The transducer of  claim 8 , wherein the non-uniform surface of the electrode comprises a roughened surface. 
     
     
         14 . The transducer of  claim 8 , further comprising a second electrode having a non-uniform shape. 
     
     
         15 . The transducer of  claim 8 , wherein the electroactive polymer has a non-uniform surface corresponding to the non-uniform shape of the electrode, such that the electrode is conformably disposed on the non-uniform surface. 
     
     
         16 . The transducer of  claim 14 , wherein the electroactive polymer has a non-uniform first surface corresponding to the non-uniform shape of the electrode and the electroactive polymer has a non-uniform second surface corresponding to the non-uniform shape of the second electrode, such that the electrode is conformably disposed on the non-uniform first surface and the second electrode is conformably disposed on the non-uniform second surface. 
     
     
         17 . The transducer of  claim 16 , wherein the polymer roll transducer actuates linearly by deflecting axially along its cylindrical axis in response to a voltage being applied across the first and second electrodes. 
     
     
         18 . The transducer of  claim 17 , wherein the non-uniform shape of the electrode and the second electrode comprises troughs and crests, such that the troughs and crests of the decrease in height and depth upon actuation of the polymer roll transducer. 
     
     
         19 . A method for fabricating an electroactive polymer transducer, the method comprising:
 disposing an electrode having a non-uniform shape on an electroactive polymer having an elastic modulus below 100 Mpa; and   creating an electroactive polymer roll by rolling the electroactive polymer such that the electroactive polymer roll has a plurality of layers of the electroactive polymer.   
     
     
         20 . The method of  claim 19 , further comprising securing the electroactive polymer roll to maintain its rolled configuration. 
     
     
         21 . The method of  claim 20 , wherein securing the electroactive polymer roll comprises attaching an end cap to at least one end of the electroactive polymer roll. 
     
     
         22 . The method of  claim 19 , wherein the non-uniform shape of the electrode comprises troughs and crests having a depth and height respectively that is substantially smaller than a thickness of the electroactive polymer. 
     
     
         23 . The method of  claim 19 , wherein creating the electroactive polymer roll comprises rolling the electroactive polymer about at least one of a support member, a mechanical linkage, an end cap, a base or combinations thereof. 
     
     
         24 . The method of  claim 20 , wherein attaching the end cap secures the electroactive polymer roll in its rolled configuration such that actuation of the electroactive polymer transducer results in linear actuation of the transducer. 
     
     
         25 . The method of  claim 19 , wherein the electroactive polymer has a non-uniform first surface, and wherein disposing the electrode having the non-uniform shape on the electroactive polymer comprises conformably disposing the electrode having the non-uniform shape on the non-uniform first surface.