Tuo Yanjing, Zhang Haifeng, Rong Wanting, Jiang Shuyue, Chen Weiping, Liu Xiaowei
Key Laboratory of Micro-Systems and Micro-Structures Manufacturing , Ministry of Education , Harbin 150001 , China.
Langmuir. 2019 Aug 27;35(34):11016-11022. doi: 10.1021/acs.langmuir.9b01040. Epub 2019 Aug 16.
In this research, the anisotropic superhydrophobic surface is prepared on a stainless steel surface by laser etching, and the drag reduction property of the anisotropic surface is studied by a self-designed solid-liquid interface friction test device. Periodic arrangement structures of quadrate scales with oblique grooves are obtained on a stainless steel surface by a laser. After modification by fluoride, the surface shows superhydrophobicity and anisotropic adhesive property. Here, the inclined direction of grooves and the inverse direction are defined as RO and OR, respectively. By changing the inclination of the grooves, a surface is obtained with a contact angle of 160° and a rolling angle difference of 6° along the RO and inverse RO direction. It is verified by numerical simulation and experiment that the subjected force of water droplets on the surface is different along the RO and inverse RO direction. Furthermore, the as-prepared surface has different drag reduction effects along the two directions. With the increase of velocity, the drag reduction effect of the superhydrophobic surface decreases against the RO direction, while the drag reduction effect along the RO direction is almost unchanged. We believe the anisotropic surface will be helpful in novel microfluid devices and shipping transportation.
在本研究中，通过激光蚀刻在不锈钢表面制备了各向异性超疏水表面，并利用自行设计的固液界面摩擦测试装置研究了该各向异性表面的减阻性能。通过激光在不锈钢表面获得了带有倾斜凹槽的方形鳞片的周期性排列结构。经氟化物改性后，该表面呈现出超疏水性和各向异性粘附性。在此，凹槽的倾斜方向和相反方向分别定义为RO和OR。通过改变凹槽的倾斜度，获得了一个表面，其沿RO方向和相反RO方向的接触角为160°，滚动角差为6°。通过数值模拟和实验验证，水滴在该表面上沿RO方向和相反RO方向所受的力不同。此外，所制备的表面沿两个方向具有不同的减阻效果。随着速度的增加，超疏水表面逆RO方向的减阻效果降低，而沿RO方向的减阻效果几乎不变。我们相信这种各向异性表面将有助于新型微流体装置和船舶运输。
