Open AccessUnderwater superoleophobic and anti-oil microlens array prepared by combing femtosecond laser wet etching and direct writing techniques
Author(s) -
Minjing Li,
Qing Yang,
Jiale Yong,
Jie Liang,
Fang Yao,
Hao Bian,
Xun Hou
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.035903
Subject(s) - microlens , materials science , femtosecond , underwater , laser , optics , nanotechnology , etching (microfabrication) , wetting , contact angle , optoelectronics , composite material , lens (geology) , layer (electronics) , oceanography , physics , geology
As an important micro-optical device, microlens array (MLA) also has broad applications in aqueous environment apart from atmosphere, such as bioscience research, ocean exploration, and microfluidic systems. However, the surface of the normal MLA is easily polluted by oil contaminations when the MLA is practically applied in a water medium, leading to the loss of its optical imaging ability. Herein, we fabricated a functional MLA with underwater anti-oil and self-cleaning abilities by combining the femtosecond laser wet etching (FLWE) and the femtosecond laser direct writing (FLDW) techniques. The as-prepared close-packed MLA is composed of 10000 single microlenses with the aperture diameter of 50 µm. The surface of each microlens is further textured with micro/nanoparticles. Clear and uniform images could be captured by using the resultant MLA in water, demonstrating great underwater imaging ability. The modulation transfer function value is larger than 0.6 at 55 lp/mm. In addition, the micro/nanostructures endow the as-fabricated MLA surface with underwater superoleophobicity and oil-repellent performance. Various oils can be repelled by the resultant MLA in water. Underwater 1,2-dichloroethane oil droplet on the textured MLA has a contact angle of 158.0 ± 0.5° and a sliding angle of 2.0 ± 0.2°. The underwater superoleophobic MLA also has good mechanical durability. The anti-oil and self-cleaning functions will broaden the applications of the MLA in ocean exploration, bioscience research, microfluidic system, and many underwater MLA-based systems.