Crystallization of lead sulfide in the presence of poly(methacrylic acid) or/and cetyltrimethylammonium bromide

PbS crystals with various morphologies, as well as PbS aggregates of crystalline subunits were successfully prepared by an aqueous-phased route employing lead nitrate and thioacetamide (TAA) as the reactants, and poly(methacrylic acid) (PMAA), cetyltrimethylammonium bromide (CTAB) and PMAA-CTAB mixed systems as crystal growth modifiers, respectively. The as-prepared products were characterized with scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was found that PMAA, CTAB and PMAA-CTAB systems show obvious influence on the crystallization of PbS crystals. Diverse polyhedral PbS crystals, spherical and coral-like aggregates of crystalline subunits of PbS could be prepared in the presence of PMAA or/and CTAB. The concentrations of PMAA or/and CTAB were turned out to be the critical factors to determine the final morphology or aggregation model of PbS crystals. The aggregation mechanisms of PbS crystalline subunits were proposed and discussed.