1. Superoleophobic and Superhydrophobic Surfaces from Microtextured ZnO-Based Surfaces on Si Substrate
- Author
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Zhi Wen Li, Qiang Zhang, Tao Li, and Chang Song Liu
- Subjects
Materials science ,Mechanical Engineering ,Diethylene glycol ,Nanotechnology ,Hexadecane ,Surface energy ,Oil drop experiment ,Contact angle ,Surface tension ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,General Materials Science ,Lotus effect ,Wetting - Abstract
Theoretical calculations suggest that creating superoleophobic surfaces would require a surface energy lower than that of any known materials. In the present work, we demonstrate micronanostructured ZnO-based surfaces displaying apparent contact angles (CA) greater than 150, even with hexadecane (surface tension l = 27.5 mN/m). The specific ZnO microtextures were fabricated by a chemical solution method, and fluoroalkylsilane (FAS) was then used to tune the surface wettability. The combination of ZnO microtextures and FAS modification resulted in a superoleophobicity with CA for hexadecane was 154.6 (161.9 for diethylene glycol (l = 45.2 mN/m). This apparent superoleophobic behavior was induced on intrinsically oleophilic materials mainly by topography (i.e. the specific ZnO microtextures), which form a composite surface of air and solid with oil drop sitting partially on air. Such special wetting state is a metastable Cassie state. The results are expected to promote the study on self-cleaning applications, especially in the condition with oil contaminations.
- Published
- 2010