Efficient fabrication of tilt micro/nanopillars on polypropylene surface with robust superhydrophobicity for directional water droplet rebound

Yu Du; Ting Wu; Xiao-Long Li; Wei-Long Zhou; Chao Ding; You-Qiang Yang; Jin-Gang Wei; Xiang Lu; Heng Xie; Jin-Ping Qu

doi:10.1016/j.isci.2022.105107

Efficient fabrication of tilt micro/nanopillars on polypropylene surface with robust superhydrophobicity for directional water droplet rebound

iScience. 2022 Sep 10;25(10):105107. doi: 10.1016/j.isci.2022.105107. eCollection 2022 Oct 21.

Authors

Yu Du^{1

2

3}, Ting Wu^{1

2

3}, Xiao-Long Li^{1

2

3}, Wei-Long Zhou^{1

2

3}, Chao Ding⁴, You-Qiang Yang⁴, Jin-Gang Wei⁴, Xiang Lu^{1

2

3}, Heng Xie^{1

2

3}, Jin-Ping Qu^{1

2

3}

Affiliations

¹ Key Laboratory of Material Chemistry for Energy Conversion and Storage (Huazhong University of Science and Technology), Ministry of Education, Huazhong University of Science & Technology, Wuhan 430074, PR China.
² Hubei Key Laboratory of Material Chemistry and Service Failure and Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Huazhong University of Science & Technology, Wuhan 430074, PR China.
³ School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China.
⁴ Kingfa Science and Technology Co., LTD., Guangzhou, Guangdong 510663, China.

Abstract

The directional rebound and transport of water droplets plays an important role in microfluidic devices, anti-fogging, and water harvesting. Herein, an extrusion compression molding and directional stretch demolding method was used to prepare a polypropylene (PP) surface with tilt micro/nanopillars with a contact angle of 157 ± 3°. The rolling angle is the highest (9 ± 4°) when the direction of rotation is opposite the tilt direction of the micro/nanopillars, showing excellent water repellency and anisotropy of the surface. Compared with the position of the first collision of the water droplet, the position of the second collision shifted ∼1.5 mm along the tilt direction of the micro/nanopillars, driven by the surface tension component during the collision. The directional rebound behavior is controlled by the droplet energy and the tilt angle. The micro/nanopillars demonstrate excellent self-cleaning property and mechanical durability, which shows the possibility of their practical engineering applications.

Keywords: Nanomaterials; Surface science; Surface treatment.