Abstract: A temperature-responsive hydrophilic-hydrophobic conversion surface has a surface property that is hydrophobic at a low temperature and is converted to be hydrophilic when the temperature rises. Accordingly, by applying the conversion surface to the fins of a heat exchanger, frost formation can be delayed in a low temperature environment due to the hydrophobicity, and remaining meltwater can be easily dried due to the conversion of the surface from hydrophobic to hydrophilic when the temperature is raised for defrosting. Therefore, the surface property of the fins of a heat exchanger is automatically converted according to the temperature and exhibits only favorable advantages at respective temperatures, so that heat transfer performance and power efficiency of the heat exchange can be effectively improved.

Abstract: A method of manufacturing hydrophilic stainless steel includes polishing the surface of the stainless steel in one direction; and immersing the polished stainless steel in an acidic solution to form an oxide film.