Polymer nanocomposite containing CdS-ZnS core-shell particles: Optical properties and morphology

Composites of nanosized CdS-ZnS core-shell particles well dispersed in polycetyl- p-vinylbenzyldimethylammonium chloride (PCVDAC) were fabricated and their optical properties and morphology were studied. The core-shell particles of less than 10 nm in size were prepared with the reverse micellar solutions formed by a polymerizable anionic surfactant, CVDAC, and a direct thermal radical polymerization of the micellar solution led to the nanocomposite containing well-dispersed core-shell particles. The shell was inferred from small angle x-ray scattering to be around a monolayer thick. This monolayer coating, however, was enough to produce an appreciable enhancement in photoluminescence for the ZnS-coated CdS system (wider band gap material on narrower band gap material), and a degradation in photoluminescence for the CdS-coated ZnS system. However, a complete coverage of the CdS core with ZnS was required to realize the photoluminescence enhancement for the ZnS-coated CdS system. The polymer domains in the composite were found to be composed of lamellar stacks due to the comb-like structure of PCVDAC. The interlamellar distance was 3.9 nm with smectic liquid crystalline texture observed under polarized optical microscope. The core-shell particles were believed to locate at the grain boundary of the liquid crystalline domains. (C) 2003 American Institute of Physics.