The Influence of New Hydrophobic Silica Nanoparticles on the Surface Properties of the Films Obtained from Bilayer Hybrids

• Published in: Nanomaterials (Basel, Switzerland) Vol. 7; no. 2; p. 47
• Main Authors: Petcu, Cristian, Purcar, Violeta, Spătaru, Cătălin-Ilie, Alexandrescu, Elvira, Şomoghi, Raluca, Trică, Bogdan, Niţu, Sabina Georgiana, Panaitescu, Denis Mihaela, Donescu, Dan, Jecu, Maria-Luiza
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20-02-2017; MDPI
• Subjects: Alkoxysilanes; Bilayers; Coatings; Fourier transforms; Glass; Hybrid structures; Hybrids; Hydrophobicity; Infrared spectroscopy; Nanoparticles; nanostructuration; Nanostructure; organic–inorganic hybrids; Polarity; Roughness; Silica; silica nanoparticles; Silicon dioxide; Sol-gel processes; sol–gel process; Surface properties; Tetramethoxysilane; Thermal stability; trialkylmonoalkoxysilanes; trialkylmonoalkoxysilanes; nanostructuration; organic–inorganic hybrids; silica nanoparticles; sol–gel process
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano7020047

Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol-gel process using hexadecyltrimethoxysilane (C
TMS) and tetramethoxysilane (TMOS) (1:4 molar ratio) as precursors. After coating, silica nanoparticles (SiO₂ NPs) functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC₈MS) were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO₂ NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO₂ NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of hydrophobic SiO₂ NPs showed that the degradation of the alkyl groups takes place in the 200-400 °C range. Bilayer coating with C
TMS/TMOS and SiO₂ NPs modified with alkoxysilane substituted with C₈ alkyl chain (SiO₂ NP-C₈) has micro/nano structure. Hydrophobicity of functionalized SiO₂ NPs-C₈ and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C
TMS/TMOS + SiO₂ NPs-C₈ (145°), compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO₂ NPs is useful for the modification of surface polarity and roughness.