Actuators with nanofiber mat electrodes: effect of electrode preparation method on actuator performance

Electrospinning (ES) is a technique that can produce nanofiber mats from arbitrary polymers. We prepared actuators consisting of nanofiber mat electrodes and ionic liquid gel using three methods and examined the effect of the preparation method on actuator performance. Experimental variables were the spinning solution concentration of the nanofiber, the coating method of poly(3,4-ethyrenedioxythiophene) (PEDOT), the type of polymer nanofiber, and the electrolyte. The results showed that actuators with nanofiber mat electrodes spun from the lowest spinning solution concentration showed a larger strain against an applied voltage, owing to a larger specific surface area. A higher conductivity and flexibility of the nanofiber mat electrode resulted in a larger strain of the actuator. In addition, when the nanofiber mat was covered with a sufficiently thin PEDOT layer by using vapor-phase polymerization, the resultant actuator became translucent. Furthermore, one of the advantages of the ES method is that it can control fiber alignment. By using the aligned nanofiber mat as an electrode, we prepared two types of actuators with different fiber directions and examined the effect of nanofiber alignment on actuator performance.