Polymer electrolyte actuator with gold electrodes

A pefluorinated cation-exchange membrane plated with noble metals was found to bend with electric stimuli in water or a saline solution. The bent to anode is almost proportional to the applied voltage around 1.5 V, which is low enough to avoid electrolysis of water. The response is as quick as muscle. Composite of preflurocarboxylic acid and electrodes gave larger displacement than that of perfluorosulfonic acid. Cold electrodes were deposited on the polymer electrolyte with large surface area by repeated plating, and showed larger displacement without gas evolution than platinum electrodes. Alkyl ammonium cation in the composite gave slower but larger displacement than alkali metal cations. The displacement of the strip of actuator in typical dimension of 0.2 mm thick and 10 mm long is more than 5 mm without gas evolution. A tubular actuator with four electrodes was fabricated with the newly developed components and bent more than 90 degree in 2 cm length to all directions.