Experimental Research and Theoretical Analysis of Surface Contact Angles of Different Materials

Abstract

Surface properties play an important role in the formation of frost crystals. The smaller the contact angle formed by droplets on the metal wall, the larger the contact area with the cold surface, thus accelerating the freezing process and making frost crystals easier to form. In this paper, the water droplets on the surface of zinc, aluminium, brass and red copper with the same specifications were observed microscopically. The images were binarized by Rising View software. The contact angles of the surfaces of different materials were measured, and the theoretical analysis and calculation were made by geometric method. It is found that the water droplets are spherical coronal on the horizontal surface. With the increase of the inclination angle of the specimen, the water droplets will incline downward, and the contact angle of the surface will be larger in front and smaller in back, and the difference between the two is equal to the inclination angle of the specimen. When the inclination angle exceeds the critical inclination angle, the water droplets will slip and no longer adhere to the metal surface.