疏水表面冷凝的可控毛细力微对象操作方法与实验

Micromanipulation Method and Experiments of Controllable Capillary Force Based on Condensation on Hydrophobic Surface

提出一种疏水表面冷凝的可控毛细力微操作方法,所研制的液滴操作手可实现操作液滴的动态控制,相应地调控液桥毛细力.建立疏水表面冷凝的单液滴生长模型,分析最小液滴半径、过冷度、饱和温度等参数的影响;通过拾取和释放理论模型,讨论微对象的拾取和释放进程;搭建微操作实验系统,实验分析疏水探针端面液滴冷凝及影响毛细力变化的因素.1 mm×1 mm×0.52 mm微型硅片(重力12.1μN)和直径200μm、壁厚4μm薄壁微球(重力5.069 n N)的操作实验验证了该方法的有效性.

On the basis of the presented micromanipulation method of condensation on hydrophobic surface, the volume of the water droplet on the hydrophobic tip surface can be dynamically varied which helps to obtain appropriate capillary lifting forces using the designed droplet micromanipulator. The single droplet growth model is established to analyze the influence of the minimum radius of droplet, the supercooling degree and the saturation temperature. Accordingly, the operational process of picking up and releasing are discussed by the theoretical models. With the assistance of a customized motion platform, the droplet formation on hydrophobic tip and the capillary lifting force generated during the manipulation process are experimentally characterized. Micromanipulation tasks of pick-and-place the micro silicon chips （1 mm＆#215;1 mm＆#215;0.52 mm, 12.1 μN） and thin-wall microspheres with diameters of 200 μm, wall thickness of 4 μm （5.069 nN） are conducted to verify the feasibility of the presented method.