Increasing hydrophobicity of sol–gel hard coatings by chemical and morphological modifications
| Autor: | Andrew Mcintosh Soutar, Xianting Zeng, Linda Y. L. Wu |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Materials science
Surfaces and Interfaces General Chemistry Surface finish engineering.material Condensed Matter Physics Microstructure Surfaces Coatings and Films Contact angle Coating Particle-size distribution Materials Chemistry engineering Surface roughness Lotus effect Composite material Sol-gel |
| Zdroj: | Surface and Coatings Technology. 198:420-424 |
| ISSN: | 0257-8972 |
| DOI: | 10.1016/j.surfcoat.2004.10.050 |
| Popis: | Sol–gel technology enables us to make scratch resistant hard coatings on plastic or non-ferrous metal substrates for industrial applications. Increasing hydrophobicity without decreasing the mechanical properties of these coatings is a challenge. We study the influence of chemical and morphological modifications on the hydrophobicity of a silica based sol–gel hard coating. To modify the chemical properties of the coating, a long side-chain alkyltrialkoxysilane is incorporated into the coating solution. To modify the surface morphology of the coating, a silica filler with selected particle size distribution is added. Varying the silica content resulted in different surface roughness and different morphology distributions. We observed a gradual increase in water contact angle with increasing roughness, and a rapid increase when the morphology changed to a lotus-leaf-like structure. We propose a new roughness parameter, the peak-to-valley ratio, to characterize morphologies with high hydrophobicity. This paper describes a single-step modification process that produces a material with microstructure and hydrophobic properties analogous to those of the lotus leaf while maintaining the coating hardness necessary for industrial applications. |
| Databáze: | OpenAIRE |
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