Mahmood Awais, Chen Shuai, Chen Lei, Liu Dong, Chen Chaolang, Weng Ding, Wang Jiadao
State Key Laboratory of Tribology, Tsinghua University Beijing 100084 China
Institute of High Performance Computing, ASTAR 138632 Singapore.
RSC Adv. 2019 Dec 18;9(72):41984-41992. doi: 10.1039/c9ra08968c.
The unidirectional transport of liquid nanodroplets is an important topic of research in the field of drug delivery, labs on chips, micro/nanofluidics, and water collection. Inspired by nature a nonparallel surface (NPS) is modelled in this study for pumpless water transport applications. The dynamics of water transport is analyzed with the aid of Molecular Dynamics (MD) simulations. There were five different types of NPSs namely A1, A2, A3, A4, and A5 utilized in this study, with separation angles equal to 5°, 7°, 9°, 11°, and 13° respectively. The water droplet was placed at the beginning of the open end of the NPS and it moved spontaneously towards the cusp of the surface in all cases except for the 13° NPS. The size of the water droplet, too, was altered and four different sizes of water droplets (3000, 4000, 5000, and 6000 molecules) were utilized in this study. Furthermore, the surface energy parameter of the NPS was also changed and four different values, 7.5 eV, 17.5 eV, 27.56 eV, 37.5 eV were assigned to the surface in order to represent a surface with hydrophobic to hydrophilic characteristics. In addition the importance of water bridge formation for its spontaneous propulsion with the influence of surface energy and droplet size is also discussed in this study. Moreover, a unique design is modelled for the practical application of water harvesting and a large size water droplet is formed by combining two water droplets placed inside a NPS.
液体纳米液滴的单向传输是药物递送、芯片实验室、微纳流体和集水领域的一个重要研究课题。受自然启发，本研究对用于无泵输水应用的非平行表面（NPS）进行了建模。借助分子动力学（MD）模拟分析了水传输的动力学。本研究使用了五种不同类型的NPS，即A1、A2、A3、A4和A5，分离角分别为5°、7°、9°、11°和13°。除了13°的NPS外，在所有情况下，水滴都放置在NPS开口端的起始处，并自发地向表面的尖端移动。本研究还改变了水滴的大小，并使用了四种不同大小的水滴（3000、4000、5000和6000个分子）。此外，还改变了NPS的表面能参数，并为表面赋予了四个不同的值，即7.5 eV、17.5 eV、27.56 eV、37.5 eV，以代表具有从疏水到亲水特性的表面。此外，本研究还讨论了水桥形成对其在表面能和液滴大小影响下自发推进的重要性。此外，还针对集水的实际应用设计了一种独特的模型，并通过将放置在NPS内的两个水滴合并形成了一个大尺寸的水滴。
