In this work, we use TiO 2 nanoparticles with average particle size 30nm and polystyrene for production nanocomposite thin films. After polystyrene was dissolved in toluene, then TiO 2 nanoparticles was added to the solution with different percentage. The obtained solutions were coated on quartz substrate using spin coater. The effect of argon RF plasma (13.6MHz, with treatment time 30-120s) on the optical properties, crystallinity, and the surface energy of PS-TiO 2 nanocomposite has been investigated. Some characterization techniques viz., X-ray diffraction analysis (XRD), UV-visible spectroscopy and contact angle measurement were used to study the induced changes on the properties of the treated PS-TiO 2 nanocomposite. Crystalinity and optical properties remained unchanged at the same conditions. Moreover, the surface energy of treated sample varied comparing to the respective untreated samples. © 2011 Elsevier B.V.