PHYS 509

For this study a layer-by layer approach was chosen, to produce electromechanical actuators with PEDOT and carbon nanotubes. The PEDOT layers were grown electrochemically on a large square block (2.5 cm x 2.5 cm) of glassy carbon electrode (GCE) from a solution of 0.020 M EDOT (3,4-ethylenedioxythiophene), TBAPF6 (tetrabutylammonium hexafluorophosphate) and 1% water in propylene carbonate. The deposition was carried out at room temperature at 1.5 volts vs. Ag/Ag+ for a specific period of time; a black film of PEDOT coated about two-third area of the GCE block that was inside the solution. The layers of PEDOT and CNTs were evaluated by AFM, Raman Spectroscopy, Electron Microscopy and mechanical testing, which indicated the formation of uniform and crystalline polymeric films with uniform layers of nanotubes in between them.

This structure exhibited improved conductivity and modulus over the control sample. During the actuation testing, the composite samples exhibited less creep during the course of a slow potential sweep experiment and faster responses to potential square waves. The addition of the carbon nanotubes did not significantly alter the magnitude of the response of the polymer. The cyclic voltammetry and in-situ conductivity tests demonstrated that the carbon nanotubes allowed better connectivity near the electrode contacts. The carbon nanotube loading was insufficient to render the polymer conductive at all potentials.