Experimental Study on Long-Term Characteristics of Water Repellency in Microcavity Structures

In recent years, research on Micro/Nano fabrication for controlling surface characteristics by forming fine patterns on a substrate has been actively conducted. In particular, the process of producing a functional film using nanoimprint lithography is a technique capable of economically and effectively producing a nano/micro structure. The manufactured functional film can be used in various fields such as antibiofouling, anti-icing, or liquid repellent surfaces. In order to utilize the water-repellent film in real life, it is not vulnerable to moisture and thus required to check the long-term characteristics of water repellency.<br/>In this study, a water-repellent surface fabricated by nanoimprint lithography was immersed into water for 100 days to check the long-term characteristic of wetting properties. The test surfaces were printed using acrylate-based photosensitive polymer with various microstructures. It has 4 types of materials and 4 types of structures, and a total of 16 types of specimens are immersed in sterilized distilled water. The contact angle is measured every 5 days to analyze the decreasing tendency of the contact angle. Then, the surface of the pattern is checked using a microscope to observe whether the pattern is deformed due to deposition or swelling.<br/>In this study, there was a case where the pattern was deformed as the time immersed in water. And in this case, it was found that the contact angle decreased. Also, the degree of pattern deformation differed depending on the material.<br/>Acknowledgement: This work was supported by Korea Institute of Energy Technology Evaluation and Planning(KETEP) grant funded by the Korea government(MOTIE)(20214000000480, Development of R&D engineers for combined cycle power plant technologies)