Highly transparent and thermally stable superhydrophobic coatings from the deposition of silica aerogels

• Published in: Applied surface science Vol. 273; pp. 776 - 786
• Main Authors: Lin, Jinbin, Chen, Hongling, Fei, Ting, Liu, Chang, Zhang, Jinlong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2013; Elsevier
• Subjects: Coating; Coatings; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fourier transforms; Heat treatment; Moisture resistance; Optimization; Physics; Silica aerogel; Sol gel process; Superhydrophobic; Thermal stability; Transparent; X-ray photoelectron spectroscopy; Moisture resistance; Silica aerogel; Superhydrophobic; Coating; Transparent; Inorganic compounds; Silicon oxides
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.02.134

Transparent superhydrophobic coatings, having high water contact angle (>160°), low sliding angle (<5°) and high transparency (transmittance closes to 90%), were prepared by using poly(methylhydrosiloxane) (PMHS) and tetraethoxysilane (TEOS) as precursors based on a simple sol–gel process. The high volume-fraction porosity structure and low surface energy are responsible for the superhydrophobicity of coating in this paper. •Transparent superhydrophobic coatings were prepared by a simple sol–gel method.•High SSA and low surface energy built the superhydrophobicity of coating.•Appropriate surface area (SSA) achieves superior superhydrophobicity coating.•The nanocoating could switch from superhydrophobic to superhydrophilic by heating. Transparent superhydrophobic coatings, having high water contact angle (>160°) and low sliding angle (<5°), were prepared by using poly(methylhydrosiloxane) (PMHS) and tetraethoxysilane (TEOS) as precursors based on a simple sol–gel process. The influence of different mass ratios of PMHS to TEOS on the transparency and superhydrophobicity of resulting coatings was investigated herein to get the optimum performance coating. The structure, composition and morphology of optimum performance coating were characterized by various technologies including Fourier transform infrared (FT-IR) spectroscopy, thermal analysis, BET, 29Si CP MAS NMR, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The optimum performance coating exhibits superhydrophobicity (CA, 164.7° and SA, 2.7°), a high transparency (transmittance closes to 90%) and a good thermal stability (up to 400°C). Note that the optimum coating directly from sol–gel process exhibits poor moisture resistance. The low surface energy and high volume-fraction porosity structure are responsible for the superhydrophobicity, transparency and thermal stability of the as-prepared coating, while the poor moisture is attributed to the untreated hydroxyl groups on the surface of coating. The moisture resistance of coating can be improved by further treated by cetyltrimethoxylsilane (CTMS), and the coating could switch from superhydrophobic (164.7°) to superhydrophilic (0°) after heat-treating at 600°C.