Investigation into the Output Force Characteristics of an Electric Actuator Based on Sodium Alginate and Polyvinyl Alcohol
Weikun Jia, Lan Wang, Haisheng Shu, Yan Xu, Gang Zhao, Fujian Fang, Yu Fu
Abstract
Research works on electric actuators made of sodium alginate have shown that the application of electric actuators in engineering has always been restricted by their small output force and stability in the process of actuation. Given the above problems, the sodium alginate-based electric actuator was improved by doping polyvinyl alcohol. First, the sodium alginate–polyvinyl alcohol actuating membrane was prepared through freeze-drying, and a three-layer structure electric actuator (SPEA) was constructed. Second, the actuation performance, mechanical and electrochemical properties, water retention rate, and tremor features of SPEA with different mass fractions of polyvinyl alcohol were studied. The results show that SPEA had optimal comprehensive performance when the mass fraction of polyvinyl alcohol was 1.0 wt %. The stable output force reached 3.459 mN at a voltage of 5 V, which was 1.64 times as high as that of SPEA without adding polyvinyl alcohol, the modulus of elasticity was 0.34 MPa, and the tensile strain reached 41.79%. Its specific capacitance was 1.4 times as high as that of SPEA without adding polyvinyl alcohol; with improved water retention performance, the internal space of SPEA was characterized by a staggering three-dimensional pore structure. In the end, the SPEA with a mass fraction of polyvinyl alcohol at 1 wt % and the electric actuator made from pure sodium alginate were tested at a stable voltage. Based on the results, the output force of SPEA was improved with its tremor being effectively suppressed.