Electroactive Textile Actuators for Soft Exoskeletons and Wearable Haptics

Conducting polymers like polypyrrole can be electrochemically oxidised and reduced. These redox reactions are accompanied by a flow of counter ions and solvents from the electrolyte into or out of the polymer matrix to maintain charge balance and osmotic pressure resulting in a 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 such conjugated polymers. First a thin layer of PEDOT (poly(3,4-ethylenedioxythiophene)) is applied to make the yarns or fabrics electrically conductive. Next, the yarns/fabrics are coated with the electromechanically active polypyrrole using electro-synthesis. Finally, the yarn/textile actuators are actuated by applying the appropriate redox potentials. To achieve in-air actuation, the yarns/fabrics are coated with ionogels, that function as the ion source/sink to drive the electrochemical reactions. Two ionogel coated yarns are assembled forming the anode/cathode pair of the electrochemical circuit enabling fully integrated, in-air actuation. Using advanced textile processing such yarn actuators are integrated into fabrics using weaving or knitting.These textile actuators can be integrated in garments such as soft exoskeletons and wearable haptic devices. The latest results of our textile actuators will be presented.