Synthesis and characterization of composites of DBSA-doped polyaniline and polystyrene-based ionomers

The synthesis of composites of n-dodecylbenzene sulfonate-doped polyaniline (PANI-DBSA) and poly(styrene-metal acrylate) ionomers is presented. The ionomers of lithium, sodium and potassium were prepared by emulsion polymerization at different styrene-to-metal acrylate weight ratios. The composites made with the potassium ionomer exhibit the largest conductivity due to the higher content of acid groups that allows stronger interactions with the PANI chains compared to the Na and Li ionomers. IR spectroscopy suggests that hydrogen bonding interactions take place between PANI-DBSA chains and that amine salt groups form by chemical reactions between the amine groups of PANI and the acid groups of the ionomer. X-ray diffraction reveals that the ionomer affects the structural ordering of PANI-DBSA. All the PANI-DBSA-ionomer composites show higher thermal stability than the PANI-DBSA material. SEM shows a characteristic agglomerate morphology in all the composites. The composite showing the highest electrical conductivity was mixed with poly(n-butyl methacrylate) (PBMA) by extrusion and the films obtained have higher electrical conductivity than that of films of the same system without ionomer.