Evaluation of time variation of hydrophobicity of silicone rubber using dynamic contact angle measurement

Dynamic contact angle measurements based on the Wilhelmy method were performed to evaluate the time variation of hydrophobicity of silicone rubber. The technique can determine both advancing and receding contact angles of a plate sample and evaluate the change of hydrophobicity in a short time. By changing the immersing time of silicone rubber into water, some aspects of overturn and/or re-orientation of polar groups at the surface were observed as a change of the contact angle. Also, the contact angle of silicone rubber was compared with that of fluorinated silicone rubber.