Dropwise condensation on a hydrophobic probe-tip for manipulating micro-objects

A capillary-gripping method that enables micro-objects to be picked up flexibly and reliably is described. By controlling the dropwise condensation on a probe tip, the volume of the water droplet on the hydrophobic tip surface can be dynamically varied, which helps to establish appropriate capillary lifting forces during micromanipulation tasks. Droplet formation and the capillary lifting forces generated during the manipulation process were experimentally characterized. Micromanipulation experiments using a customized motion platform equipped with viewing microscopes were conducted to verify the performance potential of this method. A 100% success rate in 200 trials was achieved in picking up and manipulating polystyrene microspheres with radii of 20–50 μm.