Microporous PVDF ionic membranes for actuator applications prepared with imidazole-based poly(ionic) liquid as a pore forming material

The microporous poly(vinylidene fluoride) (PVDF) membranes were prepared by phase inversion process using poly(1-ethyl-3-vinylimidazolium tetrafluorborate) (PIL) as a pore-forming agent. The membranes were activated by soaking in room temperature ionic liquids (EMImBF4 and BMImBF4) as a liquid electrolyte. The influence of PIL content on morphology and structure, electrolyte uptake of porous membranes and ionic conductivity of the activated membranes were investigated. The properties of the PVDF microporous membranes, such as crystallinity and porosity were characterized. The membrane with the maximum porosity demonstrates the highest electrical properties. The electrolyte uptake of EMImBF4 is 210 wt.% and the ionic conductivity is 9.2 mS/cm. Actuators with carbon nanotube bucky gel electrodes based on obtained membranes were prepared. The influence of ionic liquid and actuator thickness on electromechanical properties was discussed. The actuators with BMImBF4 as a electrolyte demonstrated high blocking force up to 9.5 mN. (paper)