Study of Silicone Rubber Hydrophobicity Representation Method Using Dynamic Contact Angle

Because of coarseness and solute deposition of surface,contact angle measurement of contaminated and eroded silicone rubber has hysteresis phenomenon.Dynamic contact angle method could be used to represent the hydrophobicity of silicone rubber better.The method obtained advancing contact angle and receding contact angle by injection and extraction deionized water on the surface respectively.The hydrophobicity of clean,immersed,corona and contaminated RTV(Room Temperature Vulcanization) silicone rubber coatings were measured by static contact angle method and dynamic contact angle method respectively.The result indicates that the difference between the advancing contact angle and the receding contact angle of the immersed,corona and contaminated samples is large.The measurement result of static contact angle of those samples has randomness,and easy to be influenced by delay time,so it can not reflect the surface hydrophobicity effectively,but the receding contact can reflect the surface hydrophobicity very well.The small receding angle indicates easy infiltration of the surface.In the meantime,the paper analyzed the reason of hysteresis of various samples′contact angle measurement.The study of the paper has some meaning for hydrophobicity study of silicone rubber and polymer materials.