疏水/超疏水Ti合金表面液滴的运动特性

Dynamic Characteristics of drop moving on hydrophobic/superhydrophobic Ti alloy surface

摘要:

采用激光加工技术在Ti6Al4V合金表面构建点阵微结构，利用自组装分子膜技术在微结构表面沉积低表面能物质，制备疏水/超疏水表面。采用自制测试系统测试液滴在试样表面的静态接触角和滚动角，用高速摄像机拍摄液滴滴落到试样表面的运动过程。结果表明，经激光加工和低表面能修饰构建的Ti6Al4V疏水/超疏水表面，其表面静态接触角随点阵间隔的增大而减小；液滴静态接触角与液滴滴落高度相关，同一表面上的液滴静态接触角由最后一次滴落高度决定。液滴滴落到水平试样表面的铺展系数由试样表面粗糙度和静态接触角决定，表面粗糙度和静态接触角越大，液滴铺展系数越小；液滴在倾斜表面的铺展系数随倾斜角度的增大而减小，跳跃距离随倾斜角度的增大而增大。液滴在倾斜表面的滴落运动受液滴滴落高度、试样表面滚动角和倾斜角度的影响。

Abstract:

Dotted matrix structures on Ti6Al4V surfaces with different spacing were manufactured by laser technology. The low surface energy materials were deposited on above Ti6Al4V substrates by self-assembled technique in order to prepare hydrophobic/superhydrophobic surfaces. The static contact angle and roll angle of all specimens were measured by self designed measuring system. The moving process of drop dripping was recorded by high speed camera system. The results indicate that the hydrophobic/superhydrophobic surfaces can be gained by dotted matrix structure manufacturing and self-assembled technique, and the contact angle decreases with the spacing of dotted matrix increasing. The static contact angle is relevant to the height of drop dripping, and depends on the drop volume and the last dripping height. The spreading coefficient of drop on the horizontal surface is determined by the roughness and static contact angle, the bigger the roughness and static contact angle is, the smaller the spreading coefficient. With the increase of slope angle, the spreading coefficient decreases and the jump distance increases. The movement of drop dripping on slope surfaces is greatly influenced by the dripping height, roll angel and slope angle.