Synthesis and Characterization of Zwitterionic Polymers with a Flexible Lateral Chain

In this work we report the synthesis and physical properties (thermal stability, diffraction patterns, and conductivity measurements) of a methacrylate-type polymer with zwitterionic pendant groups. The parent polymer, poly(sulfobutylbetaine of 12-ethyl-3,6,9-trioxa-12-azatetradec-1-y1 2-methylacrylate) (herein labeled PMBS-4) is used to prepare polymer/lithium salt complexes (PMBS-4/LiCl, PMBS-4/Li-triflate, and PMBS-4/LiClO4). The resulting electrolyte polymers show mechanical properties akin to elastic solids. The glass transition temperature is close to 20 C for all specimens, and PMBS-4/LiCl is thermally stable up to 187 C. The conductivity of these materials varies with temperature, following an Arrhenius-like relationship. The conductivity of the solid polymer electrolytes, SPE, follows the order PMBS-4/LiClO4 > PMBS-4/LiCl > PMBS-4/Li-triflate. The ionic conductivity of these materials is clearly affected by the anion of Li salt.