CdS nanodots preparation and crystallization in a polymeric colloidal nanoreactor and their characterizations

Abstract

Cadmium sulfide (CdS) nanodots in polymeric colloidal reactors were prepared by seeded inverse emulsion polymerization and then crystallized solvothermally. The cadmium sulfate (CdSO4)-polyacrylamide (PAM) seeds were synthesized by inverse miniemulsion polymerization with CdSO4 solution as a co-stabilizer. The prepared CdSO4-PAM particles were used as polymeric colloidal reactors for the formation of CdS-PAM by feeding the mixed solution of sodium sulfide (Na2S) and acrylamide. The effects of the feeding rate on the size, distribution and morphologies of particles were investigated. The influences of the solvothermal treating temperature and time on the crystallite size were characterized. The CdS was well formed and then crystallized in the PAM colloidal reactors. The crystals growth mechanism was taken under consideration. The crystallite size was calculated by the X-ray diffraction (XRD) data, and their morphologies were observed by transmission electron microscopy (TEM). The small CdS crystals showed a blue-shift on the spectra of ultraviolet visible absorption and fluorescence emission. The small CdS crystals displayed the desired property of photocatalytic degradation.