基于动态接触角的硅橡胶憎水性表征方法的研究

当硅橡胶受到侵蚀和染污时,由于表面变得粗糙和溶质沉淀,导致接触角测量存在滞后效应,为了更合理表征硅橡胶的憎水性,将动态接触角方法用于硅橡胶憎水性的表征。该方法对材料表面通过注水/抽水的方式获得前进角/后退角。对洁净、浸泡、电晕和表面染污后的室温硫化硅橡胶涂层样本分别使用静态接触角方法、动态接触角方法进行测量。结果发现,浸泡、染污、电晕后的样本两种方法所得结果差别较大,静态接触角测量随机性较大且易受拍照时延的影响,对表面憎水性的表征能力不够,后退角能很好地表征材料的憎水性,后退角越小,则材料表面越容易被浸润。文中同时对浸泡、电晕、染污前后表面的粗糙度增加、溶质沉淀原因进行了分析,理论上解释了接触角测量的滞后效应。笔者的研究对硅橡胶及高分子材料的憎水性研究具有一定参考价值。

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.