3A1-L01 Experimental formulation of capillary force between an adhesional wetting surface and an immersional wetting end of rod(Nano/Micro Manipulation System)

In this paper, we have reported that experimental formulation of capillary force between an adhesional wetting surface and the immersional wetting end of a rod. We have developed "Wet tweezers" for picking and placing of tiny and complex shaped objects. The wet tweezers are composed of two movable rods and two thin tubes. Two rods penetrate the liquids in corresponding thin tubes. If we contact them to an object, we can pick it up by capillary force. The wet tweezers makes a liquid bridge between an adhesional-wetting surface and an immersional-wetting end of the rod. We have observed the shape of liquid bridge and the capillary force measured by electric balance simultaneously at the various distances. Then, we have formulated the shape by using geometrical approximation. To check the accuracy of the formulation, we've compared measured value of the capillary force with the calculated value from the formula. We also discuss interesting experiments using a gel-coated rod.