Hydrophobicity and Sliding Behavior of Liquid Droplets on the Fluorinated Latex Films

Abstract

The surface properties of latex films prepared from heptadecafluorodecyl acrylate and 2,2,2-trifluoroethyl methacrylate copolymers were investigated in terms of hydrophobicity and sliding behavior of liquid droplets. The hydrophobicity of fluorinated latex films evaluated from water contact angle was closely related to the chemical composition of the surface. On the other hand, the sliding angle of liquid droplets was not directly proportional to the hydrophobicity or oleophobicity of the latex films in the present study. Although the hydrophobicity of copolymer latex films was significantly enhanced by adding small amount of highly fluorinated heptadecafluorodecyl acrylate, it made water droplets rather difficult to slide down on an inclined surface. The sliding angle of water droplet was quite sensitive to the preparation methods, namely, batch and semicontinuous emulsion polymerizations in contrast to the hydrophobicity. The surface morphology and roughness of the latex films were found to be important to explain the observations.