Xie Fei, Yang Jianjun, Ngo Chi-Vinh
The Photonics Laboratory, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
University of Chinese Academy of Sciences, Beijing 100039, China.
Results Phys. 2020 Dec;19:103606. doi: 10.1016/j.rinp.2020.103606.
Open microgroove is one kind of capillary-driven superwicking surface structure. In this study, arrays of parallel V-shaped microgrooves were fabricated on an aluminum surface by using a femtosecond laser to obtain a superwicking surface which can quickly transport the water uphill against gravity. The relationships between the flowing time and flowing distance were investigated and compared with theoretical results. We demonstrated both laser fluence and scanning step size can affect the superwicking performance. The aluminum surfaces fabricated at a laser fluence of 18.49 J/cm and 52.67 J/cm showed the best superwicking performances with the average water flow velocities approximately 16.2 mm/s and 16.4 mm/s, respectively, in the distance of 30 mm. On the other hand, the superwicking surfaces show an anisotropic flow characteristic due to the parallel microgrooves structure. However, when the scanning step size drops to 25 µm, the surface will form irregular rough structures that result in the isotropic flow characteristics. Moreover, by using a thermal camera, we found that after a 10 µL water droplet was dropped into the heated surface, the superwicking surface temperature quickly dropped from 92.4 °C to 82.5 °C which indicated that laser processing of the superwicking surface has potential application in heat dissipation.
开放微槽是一种毛细驱动的超芯吸表面结构。在本研究中，通过飞秒激光在铝表面制备了平行V形微槽阵列，以获得能够逆重力快速向上输送水的超芯吸表面。研究了流动时间与流动距离之间的关系，并与理论结果进行了比较。我们证明了激光能量密度和扫描步长都会影响超芯吸性能。在激光能量密度为18.49 J/cm和52.67 J/cm下制备的铝表面表现出最佳的超芯吸性能，在30 mm的距离内平均水流速度分别约为16.2 mm/s和16.4 mm/s。另一方面，由于平行微槽结构，超芯吸表面呈现各向异性流动特性。然而，当扫描步长降至25 µm时，表面会形成不规则的粗糙结构，导致各向同性流动特性。此外，通过使用热成像仪，我们发现将10 µL水滴滴入加热表面后，超芯吸表面温度迅速从92.4 °C降至82.5 °C，这表明超芯吸表面的激光加工在散热方面具有潜在应用。
