A simple way to achieve superhydrophobicity, controllable water adhesion, anisotropic sliding, and anisotropic wetting based on femtosecond-laser-induced line-patterned surfaces

The superhydrophobicity, controllable water adhesion, anisotropic sliding, and anisotropic wetting, which are four typical aspects of the wettability of solid surfaces, have attracted much interest in fundamental research and practical applications. However, how to use a simple and effective method to realize all those properties is still a huge challenge. Here, we present a method to realize periodic line-patterned polydimethylsiloxane (PDMS) surfaces by a femtosecond laser simply and efficiently. By adjusting the period (D) or average distance of adjacent microgrooves, the as-prepared surfaces can exhibit superhydrophobicity, controllable water adhesion, anisotropic sliding, and anisotropic wetting. We believe that these multifunctional surfaces have enormous potential applications in novel microfluidic devices, microdroplet manipulation, liquid microdroplet directional transfer, and lab-on-chips.