This paper presents the comparison between the force balance method and the surface energy method in deriving surface tension forces of some microelectromechanical systems (MEMS) problems. For studying the force balance of the capillary rise in the wick structure of heat pipes or heat spreaders, not only the surface tension at the three-phase interfaces but also the free surfaces should be carefully considered. Meanwhile the intrinsic scalar quantity of surface energy method proves its systematic feature without too much physical insight into the surface tension issues. Finally the authors used the surface energy method to study the capillary stiction of a cantilever beam during its drying process. A surface tension-driven cantilever array using for flapping micro-air-vehicles (FMAVs) is exemplified to justify the theoretical prediction in a static manner.
Journal of Applied Science and Engineering 17(3), p.223-230