Morphology, Dielectric and Thermal Properties of Poly(sulfobutylbetaine)/Montmorillonite (PMBS-4/MMT) Nanocomposites as Solid Polymer Electrolytes

Polymeric electrolyte composites based on polymer poly(sulfobutyl-betaines) (PMBS-4) and 1%, 3% and 5% montmorillonite (MMT) modified with organic ions, dodecyldimethyl(3-sulfo-propyl) ammonium hydroxide (C12SB) were synthesized. The structural modification and electrochemical properties of samples were investigated to understand the effects of organic MMT in a polymer matrix on ionic conductivity. The modification of the clay with organic ions resulted in a larger d-spacing which makes easier the penetration of PMBS-4 into the interlayer galleries. The values of T-g obtained from differential scanning calorimetry are 18 degrees C, 20 degrees C, 20 degrees C and 27 degrees C for PMBS-4, PMBS-4/C12SB-MMT 1%, PMBS-4/C12SB-MMT 3% and PMBS-4/C12SB-MMT 5% respectively. Since PMBS-4 and PMBS/C12SB-MMT were examined in the absence of Li salt, the conductivity of samples was attributed to the motion of dipoles in chains of zwitterionic PMBS-4. The increase in conductivity with increasing temperature was explained as a local structural relaxation and segmental motion of polymer. The values of sigma, at 25 degrees C, for: PMBS-4, PMBS-4/C12SB-MMT 1%, PMBS-4/C12SB-MMT 3% and PMBS-4/C12SB-MMT 5% were 6.2 x 10(-6) S/cm, 1.2 x 10(-6) S/cm, 1.7 x 10(-6) S/cm and 9.1 x 10(-6) S/cm respectively.