Design, synthesis, and self-assembly manipulating of polymerized ionic liquids contained imidazolium based on “Jacketing” effect

A series of novel polymerized ionic liquids (PILs) contained imidazolium, poly (2,5-bis{[6-(1-butyl-3′-imidazolium)hexyl] oxy carbonyl}styrene salts) (denoted as P1  X − , X − Br − , BF 4 − , PF 6 − and TFSI − ) were successfully synthesized via radical polymerization. The chemical structures of the monomers and their corresponding PILs were confirmed by 1 H NMR, 13 C NMR, and Fourier transform infrared spectroscopy. Thermogravimetric analysis results showed that these PILs had excellent thermal stability. The phase transitions and liquid-crystalline (LC) behaviors of these polymers were investigated by differential scanning calorimetry, polarized light microscopy (PLM), and wide-angle X-ray diffraction. The combined experimental results showed that all the PILs could form hexagonal columnar (ϕH) LC ordered structures because of the strong interaction between the anions and cations in the side groups except for P1  TFSI − . The conductivities of monomers and PILs were sketchily investigated, and monomers had higher conductivities than those of conprespoding PILs. For comparison, we have synthesized a polymer without counter-anion, but similar to the chemical structure of P1  X − , poly (2, 5-bis{[6-(4-butoxy-4′-oxy phenyl) hexyl] oxycarbonyl} styrene) (denoted as P2). In this case, phenyl took place of imidazolium of side chain, and LC ordered structure did not form. The comparison between P1  X − and P2 suggested that ion played an important role in the constructing of LC ordered structure. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013