Received: 10 August 2009, Revised: 2 September 2009, Accepted: 8 September 2009, Published online in Wiley Online Library: 26 October 2009 Novel properties of PES fabrics modified by corona discharge and colloidal TiO 2 nanoparticles Darka Mihailovic ´ a , Zoran S ˇ aponjic ´ b , Marija Radoic ˇic ´ b , Ricardo Molina c , Tamara Radetic ´ d , Petar Jovanc ˇic ´ a , Jovan Nedeljkovic ´ b and Maja Radetic ´ a * The objective of this study was to highlight the potential application of the corona discharge at atmospheric pressure for the surface activation of polyester (PES) fabrics in order to improve the binding efficiency of colloidal TiO 2 nanoparticles. The obtained nanocomposite textile materials provide desirable level of UV protection, self-cleaning properties, and photodegradation activity. The measured UV protection factor (UPF) of fabrics corresponds to UPF rating of 50R, designating the maximum UV protection. Additionally, the total photodegradation of methylene blue in aqueous solution was achieved after 24 hr of UV illumination and this capability was preserved and even improved after four repeated cycles. The results showed that the corona treated PES fabrics loaded with TiO 2 nanoparticles had considerably enhanced the overall efficiency compared to PES fabrics loaded only with TiO 2 nanoparticles. Copyright ß 2009 John Wiley & Sons, Ltd. Keywords: PES fabric; TiO 2 nanoparticles; corona discharge; UV protection; self-cleaning; photodegradation activity INTRODUCTION Although often presented as a novel material, titania crossed a long path from its early applications in chalking of titania-based paints to advanced applications in water and air remediation, manufacturing of sterile, self-cleaning, self-sterilizing, and anti- fogging surfaces, etc. [1] The development of simple routes for synthesis of non-toxic, inexpensive, and highly photoactive titania nanoparticles (TiO 2 NPs) expanded the range of titania commercial applications. [1] Excellent technical and economical results experienced in different sectors of industry were immediately recognized by textile companies. Recently, stimulat- ing efforts to incorporate TiO 2 NPs into the processing of high value added textile materials have been made. Recent studies indicated that UV protection as well as self-cleaning effects can be tailored by depositing TiO 2 NPs onto textile fibers, without changing the bulk properties of the fiber and deteriorating of textile appearance. [2–14] However, the poor binding of hydrophilic colloidal TiO 2 NPs to hydrophobic fibers is a key issue, that can be overcome by plasma modification of the textile surfaces. [15–16] A wide range of plasma chemical reactions can be designed by selecting appropriate operating conditions (gas, gas rate, pressure, power, treatment time) to provide the desirable effects on the textile surfaces. [17] Plasma oxidation and plasma etching induce the activation of the fiber surface, i.e. formation of new polar functional groups (C–O, C – –O, –O–C – – O, –COH, –COOH or –O–O–) facilitating the binding of TiO 2 NPs. [15–16] Previous studies confirmed that treatment of polyester (PES) fabrics by radio-frequency (RF) or microwave (MW) oxygen plasma at low pressure ensures better interaction between the surface of fibers and colloidal TiO 2 NPs. [15–16] Although low- pressure plasma systems provide better stability, uniformity and control of properties, these devices require expensive vacuum systems and complex handling of textile materials. This can be avoided by using the systems operating at atmospheric pressure (corona discharge and dielectric barrier discharge). Plasma-induced functionalities on the PES fiber surface provide enhanced interaction with highly reactive undercoordi- nated surface defect sites of TiO 2 NPs. In fact, for the particles in the nanocrystalline size range, a fraction of the surface atoms with significantly altered coordination environment and electro- chemical properties is large. [18] When diameter of nanocrystalline anatase TiO 2 particles becomes smaller than 20 nm, the surface Ti atoms adjust their coordination environment from octahedral to (wileyonlinelibrary.com) DOI: 10.1002/pat.1568 Research Article * Correspondence to: M. Radetic ´, Textile Engineering Department, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia. E-mail: maja@tmf.bg.ac.rs a D. Mihailovic ´, P. Jovanc ˇic ´, M. Radetic ´ Textile Engineering Department, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia b Z. S ˇ aponjic ´, M. Radoic ˇic ´, J. Nedeljkovic ´ Vinc ˇa Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Serbia c R. Molina Departamento de Nanotecnologı ´a Quı ´mica y Biomolecular, IIQAB-CSIC, 08034 Barcelona, Spain d T. Radetic ´ National Center for Electron Microscopy, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA Contract/grant sponsor: Ministry of Science of Republic of Serbia; contract/ grant numbers: TR 19007; 142066. Polym. Adv. Technol. 2011, 22 703–709 Copyright ß 2009 John Wiley & Sons, Ltd. 703