Physical gelation of organic solvents by low molecular weight gelators and preparation of organogel electrolytes

Three low molecular weight gelators, i.e., N-carbobenzyloxy-L-isoleucylaminooctadecane, N-carbobenzyloxy-L-valyl-L-valylaminooctadecane, and 1,12-bis(N-carbobenzyloxy-L-valyl)diaminododecane, were chosen and organogel electrolytes were prepared by physical gelation of polar solvents containing supporting electrolytes. gamma-Butyrolactone (gamma-BL), propylene carbonate (PC), and 3-methoxypropionitrile (3-MPN) were used as polar solvents. The supporting electrolytes used were LiClO4, LiBF4, and (CF3SO2)(2)NLi. The gel strength of the prepared organogel electrolytes markedly increased with increasing concentration of gelator, whereas the ionic conductivity decreased very slightly with increasing concentration. The ionic conductivity of organogel electrolytes increased in order 3-MPN < PC < gamma-BL, while the order with respect to supporting electrolytes was (CF3SO2)(2)NLi < LiBF4 < LiClO4. Arrhenius plots of ionic conductivities of organogel electrolytes indicated that the behavior of supporting electrolytes in the organogels is essentially similar to that in the isotropic solution.