Effect of upper contact line on sliding behavior of water droplet on superhydrophobic surface  

作　　者：YANG ChangWei HAO PengFei HE Feng 

机构地区：[1]School of Aerospace, Tsinghua Universtiy, Beijing, 100084, China

出　　处：《Chinese Science Bulletin》2009年第5期727-731,共5页

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 10672089 and 10872106)

摘　　要：With a low surface energy, high apparent contact angle(>150°) and low sliding angle(<5°), superhy- drophobic surface has recently been attracting a great deal of attention. The true factor determining the sliding angle still remains unclear. In this paper, various superhydrophobic silicon surfaces with pillars are fabricated by photolithography and hydrophobized with octadecyltrichlorosilane (OTS). Relations between sliding angles and micro-structured surfaces are being investigated in detail with 10 mg water droplets in C-B state and mixed state. Experimental pictures and data show that the sliding angle is independent of pillar heights from 20 to 80 μm, increasing the space between pillars causes decrease in sliding angle, and increasing the side lengths of pillars causes increase in sliding angle. Moreover, the sliding angle is irrelevant to the state of interfacial contact area of water-solid and lower contact line. It is concluded that the sliding angle of water droplet on the micro-structured surface is merely deter-mined by the upper contact line.With a low surface energy, high apparent contact angle（〉150°） and low sliding angle（〈5°）, superhydrophobic surface has recently been attracting a great deal of attention. The true factor determining the sliding angle still remains unclear. In this paper, various superhydrophobic silicon surfaces with pillars are fabricated by photolithography and hydrophobized with octadecyltrichlorosilane （OTS）. Relations between sliding angles and micro-structured surfaces are being investigated in detail with 10 mg water droplets in C-B state and mixed state. Experimental pictures and data show that the sliding angle is independent of pillar heights from 20 to 80 μm, increasing the space between pillars causes decrease in sliding angle, and increasing the side lengths of pillars causes increase in sliding angle. Moreover, the sliding angle is irrelevant to the state of interfacial contact area of water-solid and lower contact line. It is concluded that the sliding angle of water droplet on the micro-structured surface is merely determined by the upper contact line.

关 键 词：超级疏水性表面 上接触线 三相接触线 滑动角度 混合方式 三氯十八硅烷 

分 类 号：TB33[一般工业技术—材料科学与工程]