Carbon Nanotube Film Electrode and an Electroactive Device Fabricated with the Carbon Nanotube Film Electrode and a Method for Making Same

Abstract

A single wall carbon nanotube (SWCNT) film electrode (FE), all-organic electroactive device systems fabricated with the SWNT-FE, and methods for making same. The SWCNT can be replaced by multi-wall carbon nanotubes or few wall carbon nanotubes. The SWCNT film can be obtained by filtering SWCNT solution onto the surface of an anodized alumina membrane. A freestanding flexible SWCNT film can be collected by breaking up this brittle membrane. The conductivity of this SWCNT film can advantageously be higher than 280 S/cm. The EAP actuator layered with the SWNT-FE shows a higher electric field-induced strain than an EAP layered with metal electrodes because the flexible SWNT-FE relieves the restraint of the displacement of the polymeric active layer as compared to the metal electrode. In addition, if thin enough, the SWNT-FE is transparent in the visible light range, thus making it suitable for use in actuators used in optical devices.

1 - 4 . (canceled) 
     
     
         5 . A method for making an electrically conductive nanotube film, comprising the steps of:
 dispersing conductive nanotubes in a solvent under sonication;   providing a breakable porous membrane;   filtering said nanotube-containing solution onto a porous membrane;   forming a nanotube film on said membrane; and   delaminating said nanotube film from said porous membrane by breaking away said porous membrane.   
     
     
         6 . The method of  claim 5 , wherein said conductive nanotubes comprise at least one of:
 single-walled carbon nanotubes;   multi-walled carbon nanotubes;   few walled carbon nanotubes;   boron nanotubes;   boron carbon nitride nantotubes, and   boron nitride nanotubes.   
     
     
         7 . The method of  claim 5 , wherein said solvent is N,N-Dimethylacetamide. 
     
     
         8 . The method of  claim 5 , wherein said porous membrane is anodized alumina. 
     
     
         9 . The method of  claim 5 , wherein said step of forming a nanotube film on said membrane comprises the step of removing said solvent. 
     
     
         10 . The method of  claim 5 , further comprising the step of configuring the thickness of said nanotube film to achieve at least one of a desired film compliance, transparency and conductivity. 
     
     
         11 . The method of  claim 10 , wherein said step of configuring the thickness of said nanotube film comprises pressing said nanotube film. 
     
     
         12 . The method of  claim 5  wherein higher mechanical properties are achieved by utilizing acid-treated single walled nanotubes and post-sintering at above 350° C. 
     
     
         13 . An electrically conductive nanotube film prepared by the process of  claim 5 . 
     
     
         14 . A film electrode consisting of an electrically conductive nanotube film comprising a plurality of interpenetrated nanotubes, wherein the thickness of the film is configured to achieve a desired compliance required for a specific application. 
     
     
         15 . The film electrode of  claim 14 , wherein the desired compliance is the same as, or similar to, the compliance of an active layer to be used with said electrode. 
     
     
         16 . The film electrode of  claim 14 , wherein said film thickness is determined by adjusting the concentration and quantity of said interpenetrated carbon nanotubes so as to achieve a desired density 
     
     
         17 . The film electrode of  claim 14 , wherein said plurality of interpenetrated nanotubes comprise at least one of:
 single-walled carbon nanotubes;   multi-walled carbon nanotubes;   few walled carbon nanotubes;   boron nanotubes;   boron carbon nitride nanotubes, and   boron nitride nanotubes.   
     
     
         18 . The film electrode of  claim 14 , wherein said film is configured to have a conductivity of about 280 S/cm. 
     
     
         19 . The film electrode of  claim 14 , wherein said electrode is capable of operating in applications of up to about 400° C. 
     
     
         20 . The film electrode of  claim 14  wherein said thickness ranges from about several tens of nanometers to about several hundreds of micrometers. 
     
     
         21 . An electroactive device fabricated with a nanotube film electrode, comprising:
 at least one nanotube film electrode; and   at least one active layer;   wherein each of said at least one nanotube film electrode has a compliance substantially matching the compliance of said at least one active layer.   
     
     
         22 . The electroactive device of  claim 21 , wherein said active layer comprises an electroactive polymer. 
     
     
         23 . The electroactive device of  claim 21 , wherein the compliance of said at least one nanotube film electrode is controlled at least in part by its density. 
     
     
         24 . The electroactive device of  claim 21 , wherein said device is capable of functioning in high temperature applications of at least up to 220° C. 
     
     
         25 . The electroactive device of  claim 21 , wherein said nanotube film electrodes have enhanced electroactive performance in comparison with conventional electroactive devices fabricated with metal electrodes. 
     
     
         26 . The electroactive device of  claim 21 , wherein said at least one nanotube film electrode is fabricated by the method of claim  1 . 
     
     
         27 . A method for making an electroactive device having a nanotube film electrode, comprising the steps of:
 providing at least one nanotube film electrode;   providing at least one active layer;   placing said at least one nanotube film electrode in contact with said at least one active layer;   applying sufficient pressure to said at least one nanotube film electrode and said at least one active layer so as to produce an electroactive device having a substantially uniform compliance throughout.   
     
     
         28 . The method of  claim 27 , comprising the step of heating said at least one nanotube film electrode and said at least one active layer prior to applying pressure. 
     
     
         29 . The method of  claim 27 , wherein said sufficient pressure ranges between about 600 to 6000 psi. 
     
     
         30 . The method of  claim 27 , wherein said step of applying sufficient pressure comprises utilizing silicone elastomer plates on press plates. 
     
     
         31 . The method of  claim 27 , where said active layer comprises an electroactive polymer. 
     
     
         32 . The method of  claim 27 , where said at least one nanotube film electrode is made by the method of claim  1 .