The effects of low molar mass diluents on the microstructure of ionomers
The effect of polar and nonpolar low molar mass diluents on the microstructure of lightly sulfonated polystyrene (SPS) ionomers was studied using electron spin resonance spectroscopy, small-angle x-ray scattering, and dynamic mechanical analysis. Nonpolar diluents primarily affected the hydrocarbon - rich phase, while polar diluents partitioned into the ion-rich regions and disrupted the supramolecular structure. The ionic clusters remained intact, even at elevated temperatures, upon the addition of nonpolar solvents such as dodecane and dioctylphthalate. More polar solvents such as methanol and glycerol swelled the ionic domains and promoted increased mixing of the two phases.