梯度表面能材料上液滴运动机理

通过显微测量技术获得了梯度表面能材料表面的微观结构，分析了经扩散控制的硅烷化处理的硅基材料表面上表面能梯度形成的机制和影响因素。通过可视化实验，并从能量转换关系和液滴受力分析上探讨了液滴在梯度表面能材料上的快速运动机理，研究了液滴运动过程，及薄膜润滑对液滴运动速度的影响。

Mechanism of liquid droplet movement on surface with gradient surface energy

This paper aims to reveal the mechanism of droplet movement on the surface with gradient surface energy.The microscopic contour of the gradient energy surface,which was fabricated on a base of silicon chip by diffusion-controlled silanization of alkyltrichlorosilanes,was measured with atomic force microscope.It was found that there existed numerous silane groups with hydrophobic behavior on the fabricated surface whose distribution density increased with the increase of the distance from the diffusion source of silane This is the main reason for the formation of gradient surface energy.By using visual experiments,the mechanism of droplet movement on the gradient energy surface was investigated based on the analysis of the system free energy transform of the droplet.With the high speed imaging system,the effect of liquid film lubrication on droplet movement was studied visually.The experimental results showed that the energy consumption of droplet movement was compensated by the release of the system free energy caused by the gas-solid interface replaced by the liquid-solid interface of the droplet when it was moving towards the hydrophilic side of the gradient energy surface.Liquid film lubrication was favorable to the droplet movement on the gradient energy suface.