Imidazolium Ionic Liquids: Design, Synthesis And Application In PVA Based Polyelectrolyte Membranes

Ionic liquids(ILs) are composed of asymmetric organic cations and inorganic or organic anions. Compared with traditional solvents, ILs have relatively good ionic conductivities, low melting points and wide liquid ranges, which provides a new idea for prepation of conductivity materials. Ionic liquids were introduced into specific gel system,and new polyelectrolyte membranes were prepared. The electrolyte membranes have ion transpot, low phase transition temperature, heat stability, special polar environment and mechanical strength, etc. The research is helpful for improving the weakened ion transport problems of the functional materials, under the extreme condition of low temperature or high temperature.In this paper, two kinds of ionic liquids were synthesized using 1,2-dimethylimidazole,haloalkane, and halogen eater as reactants, which were three alklies imidazolium ILs[AMMIM][PF6] and ILs with ester group [EMMIM][PF6]. By cyclic voltammetry(CV)method, the electrochemical windows of [AMMIM][PF6] and [EMMIM][PF6] were analysed. [AMMIM][PF6] and [EMMIM][PF6] were characterized by FTIR, 1H NMR and their thermal stabilities were studied by TG. In addion, Electrical properties of ionic liquid-water dinary system had been investigated in detail. The results indicate that[AMMIM][PF6] and [EMMIM][PF6] have a good electrical conductivity, high electrochemical stability and thermal stability. Their electrical conductivities are above103μS·cm-1 and electrochemical windows are above 5V. Especially, it is mentioned that the ionic liquid-water dinary system can obey Arrhenius type behavior at a low concentration range.Furthermore, [AMMIM][PF6] and [EMMIM][PF6] ionic liquids were introducted into PVA based electrolyte membranes, respectively. novel PVA based electrolyte membranes were prepared successful and their electrical conductivities were above 10-5m S·cm-1. This suggests that introduction of ionic liquids contributes to improve the thermal stability,conductivity, and amorphous region fomation of PVA based electrolyte membranes. The results show that [EMMIM][PF6] can improve better the conductivities of PVA based Polyelectrolyte membranes than [AMMIM][PF6]. To sum up, this paper can provides a new idea for preparation of the new functional conductive materials.