Thermodynamic study of polymer electrolyte membrane preparation by non-solvent induced phase separation

Abstract

The composition of both the polymer solution and the non-solvent determines the resulted membrane morphology during membrane preparation through non-solvent induced phase separation (NIPS) method. In the porous polymer electrolyte membranes (PEMs), a specified porosity and uniform pore membranes are required; therefore prediction of membrane morphology is essential. The Dimensional parameter of thermodynamic was determined to find the diffusional rate between DMAc solvent and Water nonsolvent during the membranes preparation. The influences of the addition of nano-clay as filler and polyvinylpyrrolidone (PVP) addition as pore-forming agent on the thermodynamic parameter were investigated. The resulted nanocomposites were characterized by measuring their porosity and electrolyte uptake as well as by a scanning electron microscopy. The composition of non-solvent required to induce phase separation of the casting solution was determined by cloud point experiment. By adding the content of additives the binodal line shifts to polymer/solvent axis, moreover MG reduces and DSBC raises and the thermodynamic parameter increased. It was obtained that the solubility parameters (Δi/j) between solvent-additive are ΔDMAc/nano-clay = 0.787 (MPa0.5), ΔPVP/DMAc = 5.536 (MPa0.5), and The Interaction parameters (χ) are χDMAc/nano-clay = 1.661 (MPa0.5), χDMAc/PVP = 1.449 (MPa0.5).