Recently we proposed a mechanical mover device in a unimorph structure with powder hydrogen storage alloy dispersed.
A silicone rubber sheet with the alloy was piled up on another pure silicone rubber sheet, then mechanical movement was
generated by hydrogen gas absorption and desorption. Because the response of the movement was slow, therefore, in this
research we tested the additive effect of catalyst of Pd-Al<sub>2</sub>O<sub>3</sub> powder into the hydrogen storage alloy powder before
mixing with rubber. The mover device with the catalyst indicated drastically modified responses, such as higher initial
moving rate and also larger displacement. The results suggested the possibility of the device for medical purpose such as
catheter because of a powerful but tender characteristic of the device.
Perfluorosulfonic Acid (PFSA) film, commonly used in the Polymer Electrolyte Fuel Cells (PEFC), indicates
conductance of proton and permeability of H<sub>2</sub>O. In this study a mechanical composite mover device with this PFSA and
hydrogen storage alloy (HSA) thin films was made up for expecting the movement driven by volume change in the
course of hydrogen migration between PFSA and HSA layers. Hydrogen storage alloy, such as LaNi<sub>5</sub> indicates as much
as 25% of volume change in the course of H<sub>2</sub> absorption in gas phase. Using this characteristics, a mechanical mover
device was made of PFSA film of an electrolyte polymer sandwiched by hydrogen storage alloy thin films with Au-Pd
intermediate layers. The mover device was operated by migrating hydrogen ions from the PFSA layer to the HSA layer,
which were generated by electrolysis of H<sub>2</sub>O in a PFSA layer. Electrical potential was given from the outsides lead
wires. All experiments were carried out in the water. We confirmed large interesting movement generated by migration
of hydrogen ion by applying electric potentials.
Hydrogen storage alloy, such as LaNi<sub>5</sub> indicates as much as 25% of volume change in the course of H<sub>2</sub> absorption and desorption. We examined to apply this phenomenon to a mechanical mover device as a driving force controlled by the amount of hydrogen in the alloy. In this study a unimorph structural mover device was tested using HSA thin film deposited on an inert substrate. We confirmed displacements generating drastically large stresses by applying H<sub>2</sub> gas. While the amount of hydrogen in the alloy is a function of H<sub>2</sub> pressure and temperature, we also tried to control the hydrogen amount in the HSA by electric current directly applied through the film in a closed system. We report discussions on results with precise relationship between current and displacement under different temperatures. Displacement can be achieved by the temperature change caused by the electric current placed under ambient H<sub>2</sub> pressure, therefore, the results indicate the possibility of mover devices with simple structure similar to an artificial muscle controlled by electric current. From the results obtained, the test device was expected as an artificial muscle driven by hydrogen sorption reactions, which could be also controlled by electric current.