微结构梯度能表面振动液滴的运动特性
收稿日期: 2020-03-24
网络出版日期: 2021-04-30
基金资助
国家自然科学基金资助项目(51776128)
Motion Characteristics of Vibrated Droplets on Micropillared Surface with Gradient Energy
Received date: 2020-03-24
Online published: 2021-04-30
以聚二甲基硅氧烷(PDMS)为基底,采用光刻技术制备微方柱结构的梯度能表面,采用高速摄影仪对微方柱结构梯度能表面振动液滴的动力学特性进行研究,分析微方柱结构梯度能表面的几何参数对振动液滴运动特征的影响.研究发现:当对微方柱结构梯度能表面施加一定频率的振动,且振幅达到一定阈值后,液滴会产生蠕动,且随着振幅的增加,从面积分数较大的地方向面积分数较小的方向运动.在相同的振动频率下,液滴的运动加速度随着振幅的增大而逐渐减小.同时,相对于面积分数较小的区域,在面积分数较大的区域内,液滴运动的平均加速度较小;在面积分数较大的区域,湿接触直径变化的范围更大.运用力学和表面物理化学理论建立模型,分析表面微观结构对液滴运动特性的影响.
熊雪娇, 贾志海, 邓勇, 费媛媛 . 微结构梯度能表面振动液滴的运动特性[J]. 上海交通大学学报, 2021 , 55(4) : 455 -461 . DOI: 10.16183/j.cnki.jsjtu.2020.079
A gradient energy surface with micropillared structures is prepared by photolithography using polydimethylsiloxane (PDMS) as the substrate. The dynamic characteristics of vibrated droplets on the gradient energy surface with micropillared structures are studied by a high-speed camera. The influence of geometric parameters of the gradient energy surface with micropillared structures on the motion characteristics of vibrated droplets is analyzed. It is found that the droplets begin to wriggle when a certain vibration frequency is exerted on the gradient energy surface with micropillared structures and the vibration amplitude reaches a certain threshold. With the increase of the amplitude, the droplets move from the larger area fraction to the smaller area fraction. At the same vibration frequency, the acceleration of droplets gradually decreases as the amplitude increases. At the same time, compared to the region with a smaller area fraction, the acceleration of droplets motion is smaller in the region with a larger area fraction. In the region with a large area fraction, the range of wet contact diameter has a greater variation than the region with a small area fraction. A model is established using the mechanics and surface physical chemistry theory, and the influence of the surface microstructure on droplet motion characteristics is analyzed.
Key words： droplets; dynamics; surface; vibration; acceleration; gradient energy
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