Synthesis of mesostructured metal sulfide films using [M(H2O)n](NO3)2:P85 (M = Cd(II) and Zn(II)) liquid crystalline mesophases

Abstract

Transition metal salt-pluronic liquid crystalline (TMS-PLC) mesophases of A-P85, B-P85 and ((1 - x)A + xB)-P85 (where A is [Cd(H2O) 4](NO3)2, B is [Zn(H2O) 6](NO3)2 and P85 is a triblock copolymer, HO(CH2CH2O)26(CH2(CH 3)CHO)40(CH2CH2O)26H) have been used to produce mesostructured metal sulfide films. The TMS-PLC mesophases of A-P85, B-P85 and (A + B)-P85 are well ordered with a salt/P85 mole ratio between 3.0 and 11.0 with a 3D hexagonal structure. The reaction between the mesophases of A-P85, B-P85 and ((1 - x)A + xB)-P85 and H2S gas at room temperature produces mesostructured CdS, ZnS and Cd1-xZn xS films, respectively. The initial salt concentrations in the TMS-PLC phase determine the final Cd(ii) and Zn(ii) ions in the Cd 1-xZnxS crystal structure, where x can be controlled between 0.0 and 1.0. Fresh samples of the mesophase reacted under an H 2S atmosphere are continues films that slowly leach out excess P85 producing P85 rich dendrite domains and aggregates of 50 to 100 nm particles of mesostructured CdS, ZnS or Cd1-xZnxS. However, well homogenized TMS-PLC mesophases produce stable film samples upon H2S reaction.