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

Polymeric electrolyte composites based on polymer poly(sulfobutylbetaines) (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 Tg obtained from differential scanning calorimetry are 18 °C, 20 °C, 20 °C and 27 °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 σ, at 25 °C, for: PMBS‐4, PMBS‐4/C12SB‐MMT 1%, PMBS‐4/C12SB‐MMT 3% and PMBS‐4/C12SB‐MMT 5% were 6.2 × 10−6 S/cm, 1.2 × 10−6 S/cm, 1.7 × 10−6 S/cm and 9.1 × 10−6 S/cm respectively.