World Journal of Nano Science and Engineering, 2013, 3, 93-99 http://dx.doi.org/10.4236/wjnse.2013.33013 Published Online September 2013 (http://www.scirp.org/journal/wjnse) Evaluation of Energy Band Gap, Thermal Conductivity, Phase Transition Temperature and Elastic Response of PS/CdS Semiconducting Optical Nanocomposite Vishal Mathur 1,2* , Kuldeep S. Rathore 2 , Kananbala Sharma 2 1 Department of Physics, S. S. Jain Subodh P.G. College, Jaipur, India 2 Semiconductor and Polymer Science Laboratory, Department of Physics, University of Rajasthan, Jaipur, India Email: * wishalmathur@yahoo.co.in Received July 4, 2013; revised August 5, 2013; accepted August 12, 2013 Copyright © 2013 Vishal Mathur et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Thick film of Polystyrene (PS)/CdS semiconducting optical nanocomposite has been synthesized by dispersing nano- filler particles of CdS in PS matrix. The nanostructure of the CdS particles has been ascertained through X-ray Diffrac- tion (XRD) and Transmission Electron Microscopy (TEM). Small angle x-ray scattering analysis has been performed in order to ascertain nanocomposite character of the PS/CdS sample. Scanning Electron Microscopy (SEM) analyses of these samples have been carried out to establish the surface morphology. Optical Absorption Spectroscopy is used to measure the energy band gap of PS/CdS nanocomposite by using Tauc relation whereas Transient Plane Source Tech- nique is used for the determination of thermal conductivity of the prepared samples. The phase transition temperature and elastic response of the prepared samples have been ascertained through Dynamic Mechanical Analyzer (DMA). This study reveals that the thermal conductivity, Young’s modulus and the toughness of the material are greatly influ- enced by the existence of interfacial energetic interaction between dispersed CdS nanofiller particles and matrix of PS. Keywords: Polymer Nanocomposite; SAXS Analysis; Energy Band Gap; Phase Transition Temperature; Thermal Transport Property; Elastic Properties 1. Introduction Polymer nanocomposites are of great industrial and sci- entific interest, since they offer the potential for tailoring on a new scale. The thermal, mechanical and optical pro- perties of nanofilled polymers are exciting areas of re- search. This is particularly true because of the possibility of creating composites with unique combinations of functionalities, such as thermally conducting composites with good mechanical properties that are optically clear. Such properties can be realized because nanoparticles, with diameters distinctly below the Rayleigh scattering limit, still display their solid-state physical properties when embedded in transparent matrices. Optical com- posites have been defined as composites consisting of optically active nanoparticles embedded in a transparent host material, often a polymer [1]. Among various nanofillers used so far to prepare nanocomposites, semiconducting nanoparticles have at- tracted much attention because of their characteristic properties resulting from the “quantum size effect” which are significantly different from those of the correspond- ing bulk materials [2]. Many studies have been focused on cadmium sulfide (CdS) because of its high photosen- sitivity and potential application in photo-conducting cells and in devices for applications in solar cells and photo-detectors. An important field of interest for semiconductor nano- particles is their incorporation within polymers. In fact, inorganic-organic nanocomposite-based devices can be easily processed with consequent control over different electro-optical properties. Efforts have been made in the recent years to study various properties of CdS-polymer nanocomposites. Marzia Pentimalli et al. [3] reported a solid state nuclear magnetic resonance study on the thermolytic synthesis of CdS nanoparticles in a polysty- rene matrix. The study demonstrated that the annealing under vacuum produced very good quality CdS/PS nano- composites with a low content of undesired impurities. Li Chen et al. [4] reported controllable synthesis of CdS nanocrystal-polymer transparent hybrids by using poly * Corresponding author. Copyright © 2013 SciRes. WJNSE