On the capillary bridge between spherical particles of unequal size: analytical and experimental approaches

This manuscript focuses on the meridional profile of the axisymmetric capillary bridges built between two unequal-sized solid spheres. We propose an original method of resolution of Young Laplace equation based on inverse problem. The shapes of capillary bridges are classified into different categories depending on the geometrical properties, including neck radius, half-filling angle, wetting angle, and distance between two spheres. Practically, all the physical characteristics of capillary bridges, such as the free surface area of the liquid bridge and the inter-particle force, can be calculated easily. In addition, the experimental data provided in this manuscript are compared with analytical results, by matching the theoretical estimation with the data obtained from real experiments using image processing algorithm.