A Speek/PES Blend Polymer Matrix for PEMFC Application: Exploring Physico-Chemical and Structural Properties through a Theoretical Approach

In proton exchange membrane fuel cells, the substitution of hydrated Nafion ® for lower cost materials is compulsory. In this work, a material based on a two commercial polyarylenes blend, with chemical modification, has been developed. The dynamic properties of the material were evaluated, and correlated to microscopic morphology and physico-chemical properties. The material showed thermal resistance above 200 °C, and featured conductivities in the order of 10 -2 S cm -1 , measured at up to 90 °C. In order to obtain better microscopic phase separation, between the conducting polymer (sPEEK) and the structural polymer (PES), certain solvent mixtures were evaluated, based on polarity character. The NMP/DMSO (0,3/0,7 %(v/v)) solvent mixture formed the film with the best properties, under hydrated conditions. Microscopic phase separation was approached by theoretical calculation of solubility parameters as compared to experimental data. This is an unusual and promising approach, as well as modification of materials structure through solvent manipulation, which is a more practical and unexpensive procedure than synthesis of new polymer structures.