Supramolecular hydrogels of polyaniline-poly(styrene sulfonate) prepared in concentrated solutions

Polyaniline-poly(styrene sulfonate) (PAn-PSS) hydrogels have been synthesized via supramolecular self-assembly between positively-charged PAn chains and negatively-charged PSS chains. Phase diagram is plotted to systematically investigate the gelation conditions for the PAn-PSS system. A hierarchical porous microstructure consisting of oriented 1D nanofibers is observed in the hydrogels, and the phase structure, molecular structure and crystal structure are also characterized. Based on the investigation of a unique transformation of the hydrogels to colloidal particles in alkaline solutions, the electrostatic interaction is proposed to be the origin force for the gelation of the materials. Additionally, in comparison with conventional PAn-PSS colloids, as-prepared PAn-PSS hydrogels are demonstrated to possess improved capacitance performance, such as higher energy density, higher power density and better electrochemical stability. The present study gives valuable hints for achieving controlled fabrication of supramolecular materials with designed structures and outstanding properties.