This research investigates the dynamics of spontaneous droplet motion induced by wettability and shape gradients on microscale substrates. The study compares and analyzes the effects of different driving sources, including wettability gradient, shape gradient, and their combination. Findings reveal that the combination of wettability and shape gradients on a wedge-shaped track produces unique droplet motion patterns. Results demonstrate that, despite a slower initial acceleration, the combined driving force on the wedge-shaped track leads to a larger peak velocity compared to tracks with individual gradients. Additionally, the study explores the impact of track end contact angle and wedge angle on droplet motion. It highlights the preference for uniform wettability tracks for faster droplet motion, emphasizing the role of overall contact angle and wetting area. The research concludes that track size influences droplet motion, with larger wedge angles promoting faster and more stable motion. Overall, the study provides valuable insights into controlling and understanding droplet dynamics on structured surfaces.

中文翻译：

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润湿性和/或形状梯度引起固体表面上的自发液滴运动

这项研究研究了微米基底上润湿性和形状梯度引起的自发液滴运动的动力学。该研究比较并分析了不同驱动源的影响，包括润湿性梯度、形状梯度及其组合。研究结果表明，楔形轨道上的润湿性和形状梯度的结合产生了独特的液滴运动模式。结果表明，尽管初始加速度较慢，但​​与具有单独梯度的轨道相比，楔形轨道上的组合驱动力会导致更大的峰值速度。此外，该研究还探讨了轨道末端接触角和楔角对液滴运动的影响。它强调了对均匀润湿性轨迹的偏好，以实现更快的液滴运动，强调整体接触角和润湿面积的作用。研究得出的结论是，轨迹尺寸影响液滴运动，较大的楔角可促进更快、更稳定的运动。总体而言，该研究为控制和理解结构化表面上的液滴动力学提供了宝贵的见解。