TY  - EJOU
AU  - Liu, Xiaojiang 
AU  - Gu, Zhongze 
AU  - Zhou, Kun 

TI  - 3D Printing of Overhanging Microstructures for Tunable Liquid Wettability
T2  - The International Conference on Computational \& Experimental Engineering and Sciences

PY  - 2024
VL  - 29
IS  - 3
SN  - 1933-2815

AB  - Surfaces with overhanging microstructures play an essential role in surface wettability. Typically, surfaces with tightly-distributed multiply symmetric re-entrant microstructures enable the liquid suspension toward water, oil, and even n-perfluorooctane, whose surface tension is as low as 12.0 mN/m [1-4]. In contrast, surfaces with asymmetric re-entrant microstructures are favorable for unidirectional liquid spreading, where the liquids exhibit a small contact angle on the surfaces [5]. These fantastic wettability behaviors can be attributed to three-dimensional (3D) features of the overhanging microstructures, where the edge effect and Laplace pressure difference are generated on the overhanging microstructures. Based on these re-entrant microstructures, multiple functions have been realized. One typical example is the ultra-wide-angle transport based on asymmetric re-entrant microstructures, which can achieve high transport efficiency and programmable forward/lateral transport paths simultaneously. Herein, the wetting mechanisms behind these overhanging microstructures are discussed, and the intricate microstructures are constructed by 3D/4D printing techniques based on two-photon polymerization (TPP) and digital light processing (DLP). The TPP-based 3D/4D printing enables the manufacturing of 3D parts with sub-micrometer resolution but at a low speed, while the DLP-based 3D/4D printing enables the manufacturing of 3D parts at a relatively high speed but with sub-millimeter resolution. Therefore, the printing technique is carefully selected to fabricate the target surfaces for tunable liquid wettability.
KW  - Overhanging microstructures; re-entrant microstructures; two-photon polymerization; digital light processing; wettability

DO  - 10.32604/icces.2024.011320