Conducting polymer actuator based on chemically deposited polypyrrole andpolyurethane-based solid polymer electrolyte working in air

Abstract

Conducting polymers (CPs), such as polypyrrole, polythiophene, and polyaniline, areunique in that they have switchable properties due to their two or more mechanically stableoxidation states. Thus, their films or coatings can be easily switched by the application of asmall voltage and current to change their volume during electrochemical redox processes.In particular, polypyrrole (PPy) has been studied most extensively because ofits high electrical conductivity and good environmental stability under ambientconditions. In this work, we have studied a new CP actuator, fully polymeric,assembled with two PPy film electrodes and a solid polymer electrolyte (SPE),polyurethane/Mg(ClO4)2. Polyurethanes (PUs) were synthesized from4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and three typesof polyol: poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), andPPG-block-PEG-block-PPG (PPG-co-PEG). The chemical polymerization of PPy byimmersion in Py monomer aqueous solution and oxidant aqueous solution is anadequate method to prepare PU/PPy composite film as an actuator. To findthe proper thickness of the PPy coating layer for actuation, we measured thedisplacements of the actuators according to the thickness of the PPy coating layer. Thedisplacement of all actuators is discussed in connection with the properties ofthe SPE and PPy. All the results obtained in this work show the feasibility ofelectrochemomechanical devices based on PPy and SPE film being able to work inair.