An ionic polymer-metal composite actuator based on PSMI-incorporated PVDF with chemical stability and performance durability

Abstract

To develop artificial muscles with improved performance, a novel ionic polymer-metal composite (IPMC) actuator was developed by employing the newly-synthesized ionic networking film of poly (styrene-alt-maleimide) (PSMI)- incorporated poly (vinylidene fluoride) (PVDF). Scanning electron microscope and transmission electron microscopy revealed that much smaller and more uniform nano-sized platinum particles were formed on the surfaces of the film as well as within its polymer matrix after the electroless-plating process. Fourier transform infrared results suggested that no hydrolysis occurred for the as-prepared film actuator before and after the exposure to the elevated PH solutions at 25°C for 48h. The new actuator showed much larger tip displacement than that of a Nafion-based counterpart under the applied electrical stimulus, and overcame the back relaxation of the traditional IPMC actuator under the constant voltage. The current actuator was operated over 6.5h at high-frequency sinusoidal excitation, and its tip displacement was still comparable to that of the referenced Nafion actuator when the test was terminated. The excellent electromechanical performance is due to the inherent large ionic-exchange capacity and the unique hydrophilic nano-channels of the ionic networking film. Furthermore, the working principle of the developed IPMC actuator is thought to be based on a combination of piezoelectricity and ionic transport. The film of PSMI-incorporated PVDF has some advantages over the most widely-used Nafion-based one by diversifying niche applications in biomimetic motion, and the present study is believed to open a new avenue for the design and fabrication of the electro-active polymer film with unique functional properties.