Electrochemically Driven Yarn and Textile Actuators

Abstract

Conjugated polymers such as polypyrrole can be electrochemically oxidised and reduced. These redox reactions are accompanied by a flow of counter ions and solvent from the electrolyte into or out of the polymer matrix in order to maintain charge balance and osmotic pressure, resulting in an electrochemically induced volume change of the conjugated polymer. This volume change can be exploited to fabricate electrochemically driven actuators in various formats from bending bilayer microactuators to macroscopic textile actuators. Yarn and textile actuators are fabricated by coating commercially yarns and fabrics with the conjugated polymers. First a thin layer of PEDOT (poly(3,4-ethylenedioxythiophene)) is applied to make the yarns or fabrics electrically conductive. Thereafter the yarns/fabrics are coated with electromechanically active polypyrrole using electrochemical synthesis. Next the yarn or textile actuators can be actuated by applying the appropriate redox potentials. In order to achieve in-air actuation, the yarns or fabrics will be coated with novel ionogels (gelled semi-solid electrolytes), that function as the ion source/sink to drive the electrochemical reactions. Two of such ionogel coated yarns will be assembled forming the anode/cathode pair of the electrochemical circuit. Using advanced textile manufacturing such yarn actuators can be integrated into fabrics using knitting or weaving. The latest results of our textile actuators both operating in liquid electrolytes as in-air will be presented.Fig. 1 A textile actuator with 4 inlay-knitted, in-air operating yarn actuators. Figure 1