Wettability and Droplet Directional Spread Investigation of Crescent Array Surface Inspired by Slippery Zone of Nepenthes. Issue 1 (23rd November 2021)

• Record Type: Journal Article
• Authors: Jing, Xian; Si, Wenfang; Sun, Jie; Zhou, Jiakang; Lin, Jieqiong; Yu, Baojun; Lu, Mingming
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-11-23
• Subjects: anisotropic wetting -- bionic Nepenthes -- droplet directional spread -- two‐photon polymerization -- wetting surfaces; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202101231
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: In this report, the surface topography of crescent array in the Nepenthes slippery zone is measured and bionic fabricated by two‐photon polymerization (TPP) technology. A subregion outside‐in scanning method (SOSM) is proposed to solve the photoresist converge and large area surface positioning problem existing in bionic crescent array surface (BCAS) fabrication. The geometric parameters of BCAS, including area fraction, height, offset, and outer–inner radius ratio, are systematically investigated to reveal their effects on the hydrophobic performance. Perfluorinated polyether oil and fluorocarbon solvent were used to increase the hydrophobicity and homogeneity of bionic surface. The contact angles of BCASs coated with and without the solution are measured. The maximum contact angle can reach to 152.1°. What's more, considering the anisotropy of BCAS, anisotropic wetting research is conducted. Offset and outer–inner radius ratio are found to have obvious effects on the contact angle differences between convexity and concavity directions. The maximum contact angle difference can reach to 5.1°. Spreading and pinning phenomenon caused by droplet anisotropic wetting are observed and explained. This work is expected to provide references for the BCAS to be applied in super‐hydrophobic and droplets motion fields. Abstract : Bionic crescent array surface (BCAS) inspired by the slippery zone of Nepenthes pitcher is fabricated by two‐photon polymerization. The influence of geometric parameters on the wettability of BCAS is revealed. Most importantly, anisotropic wetting on BCAS is observed and explained theoretically. The unidirectional spreading capacity of BCAS is verified, which is expected to be applied in droplets motion fields.