Giant Bending Strain of Reversible Motion of Uni-Morph Soft Mover Composites Driven by Hydrogen Storage Alloy Powders Dispersed in Polyurethane Sheet

Abstract

In order to generate the bending motion operated by pressure change in hydrogen gas, soft uni-morph composites were prepared, in which composites dispersed with not only driving particles of LaNi₅ hydrogen storage alloy with Pd-Al₂O₃ catalyst powders to get high responsiveness, were piled up on a simple polyurethane sheet. Since the highest values of irreversible bending strain at the first hydrogenation (ε¹) under 0.3 MPa H₂ gas and the maximum irreversible bending strain during hydrogenation cycles (ε^m) were remarkably obtained at the 35 vol% of LaNi₅ powders dispersed in polyurethane composites, the bending strain of reversible motion was detected from the first to the 8th hydrogenation (ε_r¹ and ε_r⁸) under 0.2 MPa H₂ gas. The bending strain of reversible motion of polyurethane composites sheet is more than 2000 ppm, which was approximately equal to that of silicone rubber composites and is extremely larger than that (300 ppm) of ABS resin composites. Responsiveness (dε⁄dt) of cyclic motion of elastic deformed mover composites, which were constructed with 35 vol%LaNi₅ dispersed powder and matrix of polyurethane or silicone rubber, were more than 10 times higher than that of ABS composite.