Electro-chemo-mechanical deformation properties of polypyrrole/dodecylbenzenesulfate linear actuators in aqueous and organic electrolyte

Abstract

The immobilization of dodecylbenzenesulfonate (DBS⁻) in polypyrrole (PPy) during electropolymerization is typically expected to lead to cation-driven activity and actuation properties, at least in actuation electrolyte. Here, the complete reversal of the behavior is demonstrated, as the solvent is changed from aqueous to organic while maintaining the same electrolyte – bis(trifluoromethane)sulfonimide lithium salt. Isotonic and isometric electro-chemo-mechanical deformation (ECMD) measurements under cyclic voltammetric and square wave potential measurements yielded strain and stress values in ranges of 9–10% and 0.7–1 MPa, respectively, independent of the solvent. The morphology of PPy/DBS films also changed with the solvent exchange, while elemental analysis confirmed that fluorine atoms from the TFSI⁻ anions can be found only in the PPy/DBS films operated in organic solvent.