Uniformly shaped poly(p-phenylenediamine) microparticles:: Shape-controlled synthesis and their potential application for the removal of lead ions from water

A novel method for the shape-controlled synthesis of uniformly-shaped poly(p-phenylenediamine) (PpPD) microparticles with different morphologies under ambient condition has been developed using HAuCl4 as an oxidant and poly(N-vinylpyrrolidone) (PVP) as a surfactant. The results demonstrate that the morphologies of these microparticles can be varied from symmetrical spindle-like to diamond-like, centrosymmetric leaf-like, and parallelogram-like by tuning the concentration of reactants and their molar ratios. The length of these microparticles varies from 6 to 8 mu m while the width can be tuned from 2 to 4 mu m. The results demonstrate that PVP as a surfactant only plays a role in controlling the morphology of the polymer particles but has no influence on the polymer structures. UV-Vis absorption spectroscopy shows the formation of a complex between polymer ligands and lead ions by detection of new absorption peaks. Even though the as-prepared PpPD microparticles are only partly soluble, they still show an adsorptive affinity for lead ions.