Toyota Central R&D Labs., Inc., Nagakute, Aichi, 480-1192, Japan.
Sci Rep. 2023 Apr 20;13(1):6440. doi: 10.1038/s41598-023-33737-4.
Modified solid surfaces exhibit unique wetting behavior, such as hydrophobicity and hydrophilicity. Such behavior can passively control the fluid flow. In this study, we experimentally demonstrated a wettability-designable cell array consisting of unetched and physically etched surfaces by reactive ion etching on a silicon substrate. The etching process induced a significant surface roughness on the silicon surface. Thus, the unetched and etched surfaces have different wettabilities. By adjusting the ratio between the unetched and etched surface areas, we designed one- and two-dimensional wettability gradients for the fluid channel. Consequently, fine-tuned channels passively realized unidirectional and curved fluid motions. The design of a wettability gradient is crucial for practical and portable systems with integrated fluid channels.
经过改良的固体表面具有独特的润湿性，例如疏水性和亲水性。这种特性可以被动控制流体流动。在这项研究中，我们通过在硅衬底上进行反应离子刻蚀，实验性地展示了一种由未刻蚀和物理刻蚀表面组成的润湿性可设计的单元阵列。刻蚀过程会在硅表面引起显著的表面粗糙度。因此，未刻蚀和刻蚀表面具有不同的润湿性。通过调整未刻蚀和刻蚀表面面积的比例，我们为流体通道设计了一维和二维的润湿性梯度。结果，微调后的通道被动实现了单向和弯曲的流体运动。润湿性梯度的设计对于具有集成流体通道的实际和便携式系统至关重要。
