PREPARATION OF SIZE-QUANTIZED CDS AND ZNS PARTICLES IN NANOPHASE REACTORS PROVIDED BY BINARY LIQUIDS ADSORBED AT LAYERED SILICATES

Liquid sorption measurements of hexadecylpyridinium montmorillonite (H DPM) dispersions in ethanol (1)-cyclohexane (2) and methanol (1)-cyclo hexane (2) binary mixtures established the formation of a 0.5- to 5-nm -thick alcohol (1)-rich adsorption layer at the organoclay complex int erfaces. This adsorption layer was used as a nanophase reactor for the in situ generation of size-quantized cadmium sulfide-and zinc sulfide semiconductor particles from cadmium. (or zinc) acetate and equivalen t amounts of H2S. The volumes of the nanophase reactor in ethanol (1)- cyclohexane (2) at 1:2 = 0.05:99.95 were determined, by adsorption exc ess isotherm and X-ray diffraction measurements, to be 0.692 cm(3)/(g of HDPM) and 0.746 cm(3)/(g of HDPM), respectively. Adsorption excess isotherm and X-ray diffraction measurements gave corresponding values of 0.170 cm(3)/(g of HDPM) and 0.231 cm(3)/(g of HDPM) in methanol (1) -cyclohexane (2) at 1:2 = 0.01:99.99. As expected, smaller sized semic onductor particles were generated in the smaller nanophase reactor, pr ovided by the methanol-rich adsorption layer. Further reduction of sem iconductor particles was accomplished by decreasing the concentration of their parent ions in the nanophase reactor. Incorporation of semico nductor nanocrystallites into HDPM manifested themselves in increased viscosity Information on the fractal dimensions of the semiconductor-c lay organocomplex suspensions and that on the radius of gyration of th e nanoparticles has been determined by Small-angle X-ray scattering me asurements. The use of selectively adsorbed polar liquids at the solid binary polar-apolar liquid mixture interfaces as versatile nanophase reactors discussed.