Zinc oxide nanoparticles with surface modified by degradation of capping polymers in situ during microwave synthesis

Surface modified zinc oxide nanoparticles with variable lipophilicity were prepared by the help of microwave-assisted solvothermal synthesis from mechano-chemically prepared precursor. Sodium carbonate and zinc acetate dihydrate were used as starting materials, diethylene glycol was used as a solvent, poly(ethylene glycol) and polyvinyl alcohol were used as surface capping agents. The zinc oxide was obtained during the first three minutes of reaction and its surface was further modified with prolonged time of the reaction due to degradation of polymers used as capping and stabilising agents. Scanning Electron Microscopy was employed for powder morphology evaluation. Inorganic phase structure development was characterized by means of X-ray diffraction. Nanostructured composite materials with crystallite size below 10 nm were obtained with specific surface area varying from 35 to 86 m(2) g(-1) according to Brunauer-Emmett-Teller analysis. The progress of degradation of adsorbed polymer moieties was manifested by the powder colour change. Optical properties as well as the structure of materials were further analysed by Diffuse Reflectance Ultraviolet-visible Spectroscopy and Diffuse Reflectance Infrared Fourier Transform Spectroscopy and correlated with Thermogravimetric observations and Lipophilicity degree analysis. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.