表面活性剂与PTFE涂层结构对润湿性的影响

Wetting of surfactant solutions on superhydrophobic PTFE surface

以粗糙的超疏水聚四氟乙烯(PTFE)涂层为基体,研究表面活性剂的加入对溶液在粗糙PT-FE涂层表面润湿性的影响.利用粗糙PTFE涂层表面Cassie方程计算和原子力显微镜(AFM)对表面活性剂分子在涂层表面的形貌进行表征.结果表明,在低表面张力范围内表面活性剂溶液不能润湿粗糙的超疏水PTFE涂层,而具有相似表面张力的有机溶剂可以润湿涂层表面.表面活性剂溶液与粗糙PTFE涂层表面接触时的空气分率始终维持在0.5以上,溶液不能完全进入PTFE粗糙结构,这点是导致低表面张力的表面活性剂溶液在粗糙PTFE涂层上不能润湿的原因.

Wetting of different surfactant solutions on superhydrophobic PTFE coating was studied. The superhydrophobic PTFE surface was prepared by spray coating. Surfactant solutions were used to test the wettability of the superhydrophobic PTFE coating by contact angle measurement. The result was compared with those of the organisms. AFM was used to characterize the adsorption phenomenon of the surfactants. The result indicates that the wetting of surfactant solutions on superhydrophobic PTFE coating is heteroge- neous. For the organisms, when the surface tension is low, it is homogeneous wetting. This can be ex- plained by the adsorption of the surfactant which hinders the surfactants solutions to fill the surface structure and to decrease the air fraction.