Superoleophobic and Superhydrophobic Surfaces from Microtextured ZnO-Based Surfaces on Si Substrate

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.

• Periodical: Key Engineering Materials (Volumes 434-435)
• Pages: 538-541
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.434-435.538
• Online since: March 2010
• Authors: Chang Song Liu, Qiang Zhang, Tao Li, Zhi Wen Li
• Keywords: Lotus Effect, Metastable Cassie State, Self-Cleaning, Superoleophobic

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