Cation driven actuation for free standing PEDOT films prepared from propylene carbonate electrolytes containing TBACF3SO3

Free standing PEDOT [poly(3,4-ethylenedioxythiophene)] films (with surface conductivities of 200–400 S cm−1) were generated in tetrabutylammonium trifluromethanesulfonate (TBACF3SO3) electrolytes by potentiostatic (EP 1.05 V vs. Ag wire) electropolymerisation in propylene carbonate (at −27 °C) and methyl benzoate (at −4 °C). Films obtained in the TBACF3SO3 electrolytes showed a length increase of 2–3% during scans to negative potentials under isotonic (constant load 1.35 MPa) and stress of 0.3 MPa under isometric (constant length) conditions. Cation movement occurred due to immobilisation of CF3SO3− anions during electropolymerisation. The system showed good stability and low creep during square wave electrochemical cycling in the potential range from 0.0 to 1.0 V. The surface morphology (SEM) of the PEDOT films showed that the polymer structure is dependent upon the solvent used during the polymerisation process.