Ren Hongru, Hu Xueni, Wang Jiajia, Li NanNan, Chen Li
School of Science, Chang'an University, Xi'an 710064, China.
Langmuir. 2024 Oct 22;40(42):22338-22345. doi: 10.1021/acs.langmuir.4c03045. Epub 2024 Oct 8.
Rapid detachment of impacting droplets from solid surfaces is fundamentally interesting and important in many practical applications, including self-cleaning, anti-icing, and energy harvesting. The droplet pancake bouncing is strongly preferred for the reduced contact time and high bouncing velocity. However, the trigger conditions for pancake bouncing are rigorous. Driven by this, this work circumvents the limitations via solid surface vibration. Our results show that the impacting droplet patterns are highly sensitive to the surface vibration parameters (i.e., the vibration amplitude and frequency), and only a reasonable design of vibration parameters enables the impacting droplets to bounce in a pancake shape without the contraction stage. Intriguingly, the pancake bouncing induced by surface vibration exhibits a significant reduction of solid-liquid contact time (up to ≈80%) compared to the traditional bouncing pattern, and the bouncing velocity has been dramatically enhanced. Furthermore, the critical conditions for the pancake bouncing on the hydrophobic surface and the underlying dynamic mechanism are also identified. This work provides an effective method to achieve well-controlled pancake bouncing of impacting droplets for extensive applications.
在包括自清洁、防冰和能量收集等许多实际应用中，撞击液滴从固体表面的快速脱离在本质上既有趣又重要。液滴薄饼状弹跳因其减少的接触时间和高弹跳速度而备受青睐。然而，薄饼状弹跳的触发条件很严格。受此驱动，这项工作通过固体表面振动规避了这些限制。我们的结果表明，撞击液滴的模式对表面振动参数（即振动幅度和频率）高度敏感，只有合理设计振动参数才能使撞击液滴以薄饼形状弹跳而不经过收缩阶段。有趣的是，与传统弹跳模式相比，由表面振动引起的薄饼状弹跳使固液接触时间显著减少（高达约80%），并且弹跳速度也大幅提高。此外，还确定了疏水表面上薄饼状弹跳的临界条件及其潜在的动力学机制。这项工作提供了一种有效的方法，可实现对撞击液滴的可控薄饼状弹跳，以用于广泛的应用。
