Electrically Driven Polymer Gel Finger Working in the Air

Using ionic polymer gel that demonstrated an electric field-associated bending mo tion in aqueous solutions, an electrically driven polymer gel finger has been constructed. The material used for the finger was a hybrid gel of a cylindrical poly(vinyl alcohol)-poly(sodium acrylate) composite gel (PVA-PAA gel) rod and PVA gel film containing sodium carbonate as a skin. The working gel finger has been designed by equipping the PVA gel film of the hybrid gel with two platinum wires as electrodes. When a dc voltage was applied, the finger bent smoothly toward the positive electrode at a relatively high speed in the air. The bending of the finger occurred through a differential swelling of the PVA-PAA gel in the hybrid gel. A prototype of a microrobot hand with two gel fingers has also been designed. The hand grasped or released a piece of paper in response to electric signals.