Electrochemical and electromechanical properties of carbon black/carbon fiber composite polymer actuator with higher performance than single-walled carbon nanotube polymer actuator

The electrochemical and electromechanical properties of poly(vinylidene fluoride-co-hexafluoropropylene) based actuators using carbon black (CB)/vapor grown carbon fiber (VGCF)/ionic liquid (IL) composite gel electrodes formed without ultrasonication were compared with those of actuators using only CB or VGCF. The double-layer capacitance of the CB/VGCF/IL electrodes was larger than that of the CB/IL electrodes and increased with VGCF content. The amount of strain exhibited by the CB/VGCF/IL actuators was also larger than that for the CB/IL actuators, with the highest strain being produced for an actuator with a CB:VGCF ratio of 1:1. This was slightly larger than that for a polymer actuator using single-walled carbon nanotubes (SWCNTs), indicating that the proposed actuators exhibit sufficiently high performance for real-world applications without the need for expensive SWCNTs. Furthermore, the frequency dependence of the displacement response of the CB/VGCF/IL polymer actuators was successfully simulated using an electrochemical kinetic model similar to that for SWCNT-based actuators. The results yielded the strain in the low-frequency limit and the time constant of the response. (C) 2014 Elsevier Ltd. All rights reserved.