Integration of Great Water Repellence and Imaging Performance on a Superhydrophobic PDMS Microlens Array by Femtosecond Laser Microfabrication

Abstract

Microlens arrays (MLAs), as the important optical devices, are easily polluted by the water droplets or power‐like‐contaminates in the air. Endowing the artificial MLAs with anti‐water and self‐cleaning abilities remains great challenge. In this paper, the authors report a novel method for fabricating superhydrophobic polydimethylsiloxane (PDMS) MLAs by the combination of femtosecond laser wet etching and femtosecond laser direct writing methods. The resultant surface is composed of a convex MLA and the surrounding rough micro/nanoscale hierarchical structures. Water droplet on the surface of the as‐prepared MLA shows a contact angle of 162° and can easily roll away when the substrate is slightly tilted 0.5°. In addition to their excellent imaging performance, such ultralow adhesive and ultrahigh superhydrophobicity also endows the as‐prepared MLA with excellent anti‐water ability as well as the self‐cleaning function relative to the normal MLA. The authors believe that the anti‐water and self‐cleaning MLAs will potentially have many important applications in solar cells, medical endoscopes, and other optical systems that are often used in the humid environment or outdoors.