Conventional chemically oxidative polymerization with gradually added oxidant procedure primarily produces the agglomerated products ofpoly(m-phenylenediamine)(PmPD) due to secondary growth. This research developed a simple route to improve the conventional polymerization by just adjusting temperature to synthesize poly(m-phenylenediamine) nano-particles without catalyst or template. Morphology, molecular structure and properties of the polymer were investigated. Results showed that temperature of synthesis has a significant influence in PmPD m...