ISSN 2070-2051, Protection of Metals and Physical Chemistry of Surfaces, 2011, Vol. 47, No. 1, pp. 93–101. © Pleiades Publishing, Ltd., 2011. Original Russian Text © S.V. Gnedenkov, S.L. Sinebryukhov, D.V. Mashtalyar, V.M. Buznik, A.M. Emel’yanenko, L.B. Boinovich, 2011, published in Fizikokhimiya Poverkhnosti i Zashchita Materialov, 2011, Vol. 47, No. 1, pp. 86–94. 93 INTRODUCTION The development of high-performance, long-lived, and inexpensive hydrophobic coatings is a topical prob- lem of the present-day materials science. In the majority of cases, the hydrophobic layer is part of multifunctional composite coatings as the outer thin layer on the sup- port surface. Components of the hydrophobic layer can include fluoroorganic compounds, since the presence of fluorocarbon groups generally results in a decrease in the surface energy, the adhesion of liq- uids, and water affinity. Fluoropolymer materials are of interest for the corro- sion protection of metals due to their unique stability against various aggressive media and hydrophobicity. The use of fluoropolymers is a promising technique for obtaining coatings for various applications, including protective coatings and chemically resistant coatings with high service time; furthermore, they feature practi- cally important special properties (hydrophobicity, dura- bility, etc). However, the application of fluoropolymers for this purpose is rather limited due to their low adhesion to metallic surfaces. The adhesion of fluoropolymer materials to the support can be enhanced by applying them to preformed coatings with developed surfaces, in particular onto a layer obtained using the method of plasma electrolytic oxidation (PEO). This method can be used to form different similar ceramic coatings, including durable, corrosion-resistant, electroinsulating, and dec- orative [1]. However, due to the regularities of the pro- cess, in some instances, the obtained coating surfaces are porous, which may reduce their protective properties, particularly the resistance to corrosion. In the series of fluorinated compounds, polytetraflu- oroethylene (PTFE or Teflon) is of special interest because it features a number of unique properties based on its wide application in different braches of science and industry. The values of the contact angle of polytetraflu- oroethylene vary in the range of 98–112° [2]. The appli- cation of thin layers of polytetrafluoroethylene to a rough support surface may impart high hydrophobicity. These surfaces are promising for wide practical applications. The additional treatment of surface layers on titanium alloys by superdispersed polytetrafluoroethylene (UPTFE, Forum ® ) and its low-molecular fractions, which are the products of secondary UPTFE pyrolysis after the PEO process allows one to obtain homogeneous and compact coatings [3]. This surface modification by fluoropolymer materials results in an increase in its hydrophobicity and composition coatings acquire addi- tional protective properties [4, 5]. An important factor in the procedure of PTFE application is obtaining UPTFE according to the method of PTFE waste thermal treat- ment [6]. This enhances the technological, economical, and environmental significance of developments based on using UPTFE and its oligomeric (low-molecular) fractions. The aim of this work was to study the hydrophobic properties of the coatings formed on a titanium surface using the PEO method with further treatment by differ- ent superdispersed polytetrafluoroethylene fractions obtained using the gas-dynamic thermal destruction of Hydrophobic Properties of Composite Fluoropolymer Coatings on Titanium S. V. Gnedenkov a , S. L. Sinebryukhov a , D. V. Mashtalyar a , V. M. Buznik b , A. M. Emel’yanenko c , and L. B. Boinovich c a Institute of Chemistry, Far East Branch of the Russian Academy of Sciences, 100-letiya Vladivostoka prospect 159, 690022 Vladivostok, Russia b Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninskii prospect 49, 119991 Moscow, Russia c Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, GSP-1, 119991 Moscow, Russia e-mail: svg21@hotmail.com Received April 21, 2010 Abstract—The results of studies of the hydrophobicity of composite coatings on titanium formed using the method of plasma electrolytic oxidation (PEO) with further treatment by superdispersed polytetrafluoroeth- ylene and its low-molecular fractions are presented. The chosen regimes of application of fluoropolymer materials of different fractional composition onto oxide coatings allow enhancing significantly hydrophobic surface properties (the contact angle reaches 131°). DOI: 10.1134/S2070205111010047 PHYSICOCHEMICAL PROBLEMS OF MATERIALS PROTECTION