Superhydrophobic polyester-based fabrics modified by barrier discharge plasma and organosilanes Igor Novák a , Marian Valentin a , Zdeno Špitalský, Anton Popelka b , Jozef Šesták c , Igor Krupa d a Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava 45, Slovakia b Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar c VUTCH-CHEMITEX, Rybniky 954, Zilina 01168, Slovakia d QAPCO Polymer Chair, Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar E-mail: Igor.Novak@savba.sk Abstract In this paper, a diffuse coplanar surface barrier discharge plasma at atmospheric pressure has been used to surface modification of polyester/cotton (PESc) fabric, that was subsequently modified by sol-gel process using suitable organofunctional silanes to enhance its hydrophobicity. Modified PESc fabric surfaces were conditioned during the gelling process to obtain the permanent hydrophobicity. The contact angle of water before washing of plasma and sol gel pre-treated PESc fabric was found to be of 154°, and 151° after standardized washings. It was also demonstrated that the process is applicable at the industrial scale. Key words: cotton, fabric, plasma treatment, polyester, sol gel, silanes, hydrophobicity Introduction Polyester/cotton (PESc) fabrics are the most produced fabrics in the textile industry. Their surfaces are rich in polar groups, which make them hydrophilic, but in some special cases, there is a need for hydrophobic surfaces. There are many methods with which to modify the surface of polymeric fabrics, one of which is low-temperature discharge plasma technology. This modification method has become more and more popular because it does not require a large amount of conventional chemicals, benefitting not only the economy but also the environment. Sol-Gel chemistry is relatively low cost process running at low temperature in environmentally friendly solvents which allows a formation of infinity number of different structures (1). It is based on the polycondensation of molecular precursors such as metal alkoxides, consisting of silicon, titanium, zirconium or other metallic elements in their structure (2). Hydrolysis and condensation of these alkoxides lead to the formation of metal oxopolymers. The mild characteristics offered by the sol-gel process allows the introduction of organic molecules inside an inorganic network what also increases a variability of a potential application (3-5). The nanostructures based on sol gel chemistry can be prepared in the form of particles, bulk material, fibers, and, mainly as thin films which can be deposited on the surface of various substrates including plastics and fabrics (6 – 10). From these reason it is clear that those technologies attracted an attention of researchers, textile producers and convertors to design textile materials with enhanced functionality. In this contribution we refer the results on the development of new hydrophobic plasma treatment of polyester/cotton fabrics by barrier discharge plasma and subsequently sol – gel procedure using a combination of alkylsilane and fluorosilane. The fixation of silica deposits on the fabric was insured by diffuse coplanar surface barrier discharge (DCSBD) plasma. The washing fastness test demonstrated a high stability of treated surface. The applied route was successfully tested at semi-industrial scale.