Lateral capillary forces of cylindrical fluid menisci : an experimental, analytical and numerical study.

International audienceSelf-assembly and self-alignment driven by capillary meniscus forces are presently at the core of many important technological applications, including solder bonding in flip-chip assembly and fluidic self-assembly for microelectronic packaging. Lateral capillary meniscus forces were object of substantial theoretical and numerical modeling in recent years. Anyway, these studies were unsatisfactorily supported by direct experimental investigations. In this paper we present a comprehensive study of lateral capillary forces of cylindrical menisci, where experimental, analytical and numerical analyses of the same physical system are compared. We describe the conceptually simple experimental apparatus we designed to investigate lateral forces arising from small perturbations of cilindrical liquid menisci. The apparatus allowed controlling all physical and geometrical parameters relevant to the experiments. We then reproduce our experimental data with a novel analytical model of lateral fluid meniscus forces and with finite element simulations. The remarkable agreement between our experiments and models, while confirming earlier reports, provides a solid foundation for all applications of lateral capillary forces. Moreover, our experimental apparatus may be used as testbed for further experimental investigations of confined fluid menisci