Polymerized organic-inorganic synthesis of nanocrystalline zinc oxide

Zinc oxide (ZnO) nanobeads were synthesized by aqueous polymer thermolysis method in air. The precursor powders were prepared using different polymers of varied molecular weights. The influence of annealing temperature from 300 to 1000 degrees C on thermal properties of polymer Gel precursors and ZnO nanoparticles is investigated systematically using thermogravimetric analysis (TGA). The nature and structure of different polymers and their affinity towards the solvent seem to be responsible for the formation of ZnO and their surface morphology. X-ray diffraction studies of the synthesized ZnO show polycrystalline hexagonal zincite syn structure. The composition and microstructural features of polycrystalline samples of zinc oxide were studied by IFTIR, SEM and TEM. Infrared spectra reveal the formation of zinc oxide and the removal of organic matter at higher temperature. The as prepared samples, synthesized by poly-vinyl alcohol (PVA) of molecular weight 14,000 and 125,000 were decomposed by heating in air. resulting in the formation of spherical and cuboid shapes of ZnO. The results are compared with those of poly-vinyl pyrrolidone (PVP) capped ZnO. The smallest grain size was found in presence of PVP. The role of polymer interactions in the synthesis for obtaining well-dispersed crystallites has also been demonstrated. (c) 2007 Elsevier B.V. All rights reserved.