Study on the creation of fine periodic structure on V-shaped groove with short-pulsed laser

Functional surface creation technologies have gar-nered increasing attention over the years. These technologies can provide various functions to a material by establishing a fine structure on the material surface and responding to the needs of industrial products with distinguished functions or high values. In addi-tion, by creating a “composite fine structure,” which is composed of two kinds of structures with different scales, the enhancement of functions and emergence of new functionalities can be expected. Hence, our study combined a micrometer-scale V-shaped groove structure using an ultra-precision cutting and nanometer-scale ultra-fine periodic structure (LIPSS) using a short-pulsed laser. Then, we clarified the creation principle and studied the functionality of the struc-ture, specifically, its wettability. As a result, it was found that optical behavior inside the V-shaped groove changed; therefore, the composite structure changed depending on the groove angle, laser polarization di-rection, and number of times of irradiation. In addi-tion, it was found that the water wettability changed depending on the type of formed micro-nano composite structures. Moreover, the wettability could be con-trolled by depending on how the structure is used.