High performance polymer actuator based on carbon nanotube-ionic liquid gel: Effect of ionic liquid

In this study, we investigated a dependence of anionic species of ionic liquids (ILs) (IL: perfluoroalkyltrifluoroborate anions ([CnF2n+1BF3]− (n = 0, 1, 2) and bis(perfluoroalkylsulfonyl)imide anions ([(CmF2m+1SO2)(CnF2n+1SO2)N]− (m, n = 0, 1, 2)) on electrochemical and electromechanical properties. 1-Ethyl-3-methylimidazolium (EMI+) was selected as a cation for ILs. 1-Ethyl-3-methylimidazolium trifluoromethyltrifluoroborate (EMI[CF3BF3]), 1-ethyl-3-methylimidazolium pentafluoroethyltrifluoroborate (EMI[CF3CF2BF3]), 1-ethyl-3-methylimidazolium fluorosulfonyl(trifluoromethylsulfonyl)imide (EMI[FTA]) and 1-ethyl-3-methylimidazolium pentafluoroethylsulfonyl(trifluoromethylsulfonyl)imide (EMI[C1C2]) were synthesized according to the literatures. The generated strains of the bucky-gel electrodes of the actuators containing EMI[CF3BF3] (in the high frequency range: 10–0.5 Hz) and EMI[CF3CF2BF3] (in the high frequency range of 1–0.5 Hz) are larger than that containing EMI[BF4] (that is to say the quick response). For low frequencies (0.1–0.005 Hz), the generated strain containing EMI[CF3CF2BF3] was larger than those containing other ILs (EMI[CnF2n+1BF3] (n = 0, 1) and EMI[(CmF2m+1SO2)(CnF2n+1SO2)N] (m, n = 0, 1, 2)). The Youngʹs modulus of actuators containing EMI[CF3BF3] and EMI[CF3CF2BF3] were 145 and 110 MPa, respectively. The melting points of EMI[CF3BF3] and EMI[CF3CF2BF3] are lower than that of EMI[BF4]. ore, trifluoromethyltrifluoroborate ([CF3BF3]−) and pentafluoroethyltrifluoroborate ([CF3CF2BF3]−) anions performed much better as the actuator using the polymer-supported bucky-gel electrode containing the IL. These results are considered to be the actuator enough to apply actual applications (e.g. tactile display).