Synthesis and characterization of PMMA/ZnO nanocomposite films

Full text: Zinc oxide (ZnO) is a n-type semiconductor that has a broad band gap energy (3.6 eV) and an excitation energy of approximately 60 meV. Due to its optical and electrical properties it has been widely applied as varistor and gas sensor, field emitter, UV laser, etc. Poly(methyl methacrylate) (PMMA) is an acrylic polymer with good mechanical and interesting optical properties. It is a transparent and conductive polymer and can be widely used in the composite materials production with large applications [1]. PMMA/ZnO nanocomposite films were prepared with different contents of ZnO dispersed in the PMMA matrix. ZnO with an average crystallite size of 25 nm was synthesized by an adapted sol-gel method using water as solvent. The nanocomposite films were characterized by X-Ray Diffraction (XRD), Photoacoustic Absorption Spectroscopy (PAS) and Scanning Electron Microscopy (SEM). XRD diffractograms showed that ZnO crystallites are present in the PMMA/ZnO films. The PAS showed that the PMMA/ZnO nanocomposite films exhibit intense absorption band at about 350 nm characteristics of ZnO nanostructured. SEM images of the films showed that ZnO nanoparticles are uniformly dispersed in the PMMA matrix, however the nanoparticles tend to agglomerate with increases ZnO content. This results showed that this material could be applied as transparent UV-protective coatings or UV-shielding windows [2]. References: [1] H. Chakraborty, A. Sinha, et al. A study on nanoindentation and tribological behavior of multifunctional ZnO/PMMA nanocomposite. Mater. Lett. 93 (2013) 137-140. [2] L. Zhang, F. Li, et al. Synthesis of transparent ZnO/PMMA nanocomposite films through free-radical copolymerization of asymmetric zinc methacrylate acetate and in-situ thermal decomposition. J. Lumin. 131 (2011) 1701-1706. (author)