Proton conduction and methanol transport through sulfonated poly(styrene-b-ethylene/butylene-b-styrene)/clay nanocomposite

Abstract

Sulfonated poly(styrene-b-ethylene/butylene-b-styrene)(S-SEBS)/clay composite membranes incorporating various types of clay were prepared to reduce the methanol permeability in a direct methanol fuel cell(DMFC). The dispersion of clay into the polymer matrix was confirmed by TEM. The water uptake and state were measured by DSC to understand the effect of the incorporation of clay types on the membrane hydrophilicity. These results showed a strong relationship between the proton conductivity and hydrophilicity of the clay. The thermal stability of the composite membrane was examined and the water evaporation rate at 100 A degrees C was varied by the total amount of absorbed water. The highest proton conductivity and the lowest methanol permeability were obtained with the S-SEBS-Na+ membrane; these properties were affected by the hydrophilicity, interlayer spacing and dispersibility of clay.