Tang Biao, Meng Chuanzhi, Zhuang Lei, Groenewold Jan, Qian Yuyang, Sun Zhongqian, Liu Xueli, Gao Jun, Zhou Guofu
National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China.
Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.
ACS Appl Mater Interfaces. 2020 Aug 26;12(34):38723-38729. doi: 10.1021/acsami.0c06389. Epub 2020 Aug 12.
Transporting oil droplets is crucial for a wide range of industrial and biomedical applications but remains highly challenging due to the large contact angle hysteresis on most solid surfaces. A liquid-infused slippery surface has a low hysteresis contact angle and is a highly promising platform if sufficient wettability gradient can be created. Current strategies used to create wettability gradient typically rely on the engineering of the chemical composition or geometrical structure. However, these strategies are inefficient on a slippery surface because the infused liquid tends to conceal the gradient in the chemical composition and small-scale geometrical structure. Magnifying the structure, on the other hand, will significantly distort the surface topography, which is unwanted in practice. In this study, we address this challenge by introducing a field-induced wettability gradient on a flat slippery surface. By printing radial electrodes array, we can pattern the electric field, which induces gradient contact angles. Theoretical analysis and experimental results reveal that the droplet transport behavior can be captured by a nondimensional electric Bond number. Our surface enables no-loss transport of various types of droplets, which we expect to find important applications such as heat transfer, anticontamination, microfluidics, and biochemical analysis.
运输油滴对于广泛的工业和生物医学应用至关重要，但由于大多数固体表面上存在较大的接触角滞后现象，这一过程仍然极具挑战性。注入液体的光滑表面具有低滞后接触角，如果能够产生足够的润湿性梯度，它将是一个非常有前景的平台。目前用于产生润湿性梯度的策略通常依赖于化学成分或几何结构的设计。然而，这些策略在光滑表面上效率不高，因为注入的液体往往会掩盖化学成分和小尺度几何结构中的梯度。另一方面，放大结构会显著扭曲表面形貌，这在实际应用中是不可取的。在本研究中，我们通过在平坦的光滑表面上引入场诱导润湿性梯度来应对这一挑战。通过印刷径向电极阵列，我们可以对电场进行图案化，从而诱导出梯度接触角。理论分析和实验结果表明，液滴传输行为可以用无量纲电邦德数来描述。我们的表面能够实现各种类型液滴的无损耗传输，我们期望它能在诸如传热、防污染、微流体和生化分析等重要应用中找到用武之地。
