Recently, we developed hot-pressing method to enhance the actuating force of ionic polymer-metal composite(IPMC)
by increasing the thickness of IPMC membrane and proved it to be effective in the previous research. In the present
work, water-uptake and mechanical properties of the hot-pressed Nafion membrane were measured and compared with
those of bare Nafion. We observed slight change of mechanical properties with respect to the increase of laminated
Nafion films and assumed the property change of the hot-pressed Nafion is due to the interlayers between laminated
Nafion films. Then we applied classical laminated plate theory assuming the existence of interlayer in the hot-pressed
Nafion and the analytic results agreed well with the experimental results.
On purpose to overcome the limit of conventional ionic polymer-metal composites (IPMC) using the commercial ionic membranes, novel IPMCs with radiation-grafted ion-exchange membranes were prepared. Poly(vinylidenefluoride-<i>co</i>-hexafluoropropylene) (PVDF-<i>co</i>-HFP) and poly(ethylene-<i>co</i>-tetrafluoroethylene) (ETFE) were radiation-grafted with styrene, and then sulfonated. The properties of the membranes were modulated by controlling the amount of polystyrene sulfonic acid (PSSA) groups in the membranes. The amount of PSSA groups were tuned by controlling the total absorbed dose of γ-ray. The membranes were characterized by measuring the water-uptake, the ion-exchange capacity, and the ion conductivity. The performance of the IPMCs using these membranes were analyzed with laser displacement meter. They exhibited much larger bending displacement in comparison with Nafion-based IPMC. With increasing the amount of PSSA groups, the maximum displacement and the bending speed were remarkably increased. The results made sure that the property of ion-exchange membrane was the key element affecting the actuation performance of IPMC.