Controlled hydrophilic/hydrophobic property of silica films by manipulating the hydrolysis and condensation of tetraethoxysilane

• Published in: Applied surface science Vol. 376; pp. 1 - 9
• Main Authors: Yang, Xin, Zhu, Liqun, Chen, Yichi, Bao, Baiqing, Xu, Jinlong, Zhou, Weiwei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2016
• Subjects: Condensation; Control surfaces; Controlled wettability; Heat treatment; Hydrolysis; Silica film; Silicon dioxide; Sol gel process; Tetraethoxysilane; Topography; Wettability; Hydrolysis; Silica film; Controlled wettability; Tetraethoxysilane; Condensation
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.02.068

•The silica films exhibiting controllable and wide range wettability are prepared.•Hydrophilic and hydrophobic groups on particles are controlled by one step method.•The wettability of films can be changed from hydrophobicity to hydrophilicity.•The change trend of contact angle is indicated by an equation.•The silica film is useful for the wettability change of different materials surface. Controlling surface wettability is an important road to afford the materials with anticipated functional properties, such as anti-fogging, anti-icing and self-cleaning. Manipulating the surface topography and chemical composition is a promising strategy to achieve the expected functional properties. Herein, we concurrently realized the control of surface topography and chemical composition of the film materials via exploiting a simply one step method through the hydrolysis and condensation of tetraethoxysilane (TEOS) to form silica sol-gel films. By adjusting the amount of water, TEOS and basic catalyst, the hydrophilic or hydrophobic chemical groups on the silica particles surface were well controlled. As a result, the sol-gel silica films exhibiting a controllable and wide range contact angles from 7.7±1.5° to 121.6±1.8° were obtained by this simple one-step method. The inorganic nonmetallic, metallic and polymer materials surface could maintain different wettability by the modification of controlled wettability silica films. Furthermore the wettability of silica film could be easily changed from hydrophobicity to superhydrophilicity through a heat-treatment due to the decrease of hydrophobic chemical groups conforming to the time-temperature equivalence principle. Raising temperature and extending holding time were equivalent to chemical bond breaking which result in the wettability change of silica films.