Co-solvent effect on conductivity of composite electrolytes comprising polyethylene oxide and polytetramethylene glycol-based waterborne polyurethane via a mixture design approach

The co-solvent effect of the three solvents, ethylene carbonate (EC), propylene carbonate (PC), and diethylene carbonate (DEC) on the composite electrolytes (CE) consisting of polyethylene oxide (PEO) and polytetramethylene glycol-based waterborne polyurethane [WPU(PTMG)] was investigated by using a mixture design approach. The conductivity data at temperatures of 5, 25, 45 and 65 °C were fitted by employing a forward stepwise regression procedure. Unfortunately, as a result of negligible conductivity of EC at T_m (approximately 40 °C), the test statistics gave values for R_adj² as 0.69 and 0.71 for the regression equations at 5 and 25 °C, respectively. The regression equations at 45 and 65 °C were used to construct contour plots which facilitated the comparison of synergistic/antagonistic effects among the selected solvents. Molecular simulation was also made on the basis of the radius distribution function. The results obtained are used to interpret the results through contour plots and also using the physical properties of the solvents.