Gels of ionic liquid [C4mim]PF6 formed by self-assembly of gelators and their electrochemical properties

Three types of gelators, bis(4-octanoylaminophenyl) ether (BODE), bis(4-octanoylaminophenyl) methane (BODM) and 2,4′-bis(octanureido) toluene (BOUT) were utilized as gelators for the gelation of ionic liquid 1-butyl-3-menthyl-imidazolium hexafluorophosphate ([C4mim]PF6). The mean minimum gelator concentrations (MGCs) for the [C4mim]PF6 were found to be less than 2 wt%. The polarized optical microscopy image of [C4mim]PF6 gels reveals the formation of spherical crystallites resulting from the fibrillar aggregates of the gelators. The cyclic voltammograms of the [C4mim]PF6 gels indicate a good electrochemical stability over the range from −3.0 to 3.0 V. The impedance spectra of the [C4mim]PF6 gels show good linear relationships between ion conductivity and temperature, indicating that the temperature dependence of the conductivity follows the classical Arrhenius equation.