Roughness-dependent hydrophobicity of polydimethylsiloxane grafted titanium thin films

• Published in: Surface & coatings technology Vol. 483; p. 130749
• Main Authors: Foadi, Farnaz, Celik, Nusret, Esidir, Abidin, Onses, Mustafa Serdar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2024
• Subjects: Hydrophobicity; Liquid-like surfaces; Roughness; Titanium thin films; Wetting states; Wetting states; Hydrophobicity; Titanium thin films; Liquid-like surfaces; Roughness
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2024.130749

Understanding the wetting behavior of thin films is essential for advanced coatings applications. This paper studies the roughness dependent hydrophobicity of titanium thin films deposited by radio frequency magnetron sputtering. The grafting of mechanochemically activated polydimethylsiloxane (PDMS) onto a titanium thin film is achieved by benefiting from the self-formation of an oxide layer during the sputter-coating process. PDMS grafting results in a liquid-like hydrophobic layer with a nanoscopic (<3 nm) thickness, which makes it possible to investigate the roughness dependent wetting behavior of titanium films. In addition to the structural characterization, atomic force microscopy imaging was used to derive different morphological parameters. Correlating static and dynamic water contact angle measurements with these morphological parameters enabled identification of different wetting states. The findings of this study contribute to the design and fabrication of stochastically structured hydrophobic surfaces with a stable wetting state that is needed in practical applications. •Mechanochemical grafting of PDMS results in hydrophobic modification of titanium thin films.•Self-formation of an oxide layer during sputter-coating enables grafting of PDMS.•The wettability of hydrophobic thin films with random roughness during temporal roughness evolution is presented.•The Laplace pressure and energy of the system showed the tendency towards the stable wetting state.•Understanding of roughness-dependent hydrophobicity is critical for applications.