Rupture energy and wetting behavior of pendular liquid bridges in relation to the spherical agglomeration process

A novel micro force balance (MFB) is used to investigate the rupture energy of a silicon oil liquid bridge formed in water between two glass particles of either the same or dissimilar surface energy. Rupture energies are integrated from force curves and compared with the models proposed by Simons et al. (Chem. Eng. Sci. 49 (1994) 2331) and Pitois et al. (Eur. Phys. J. B 23 (2001) 79). The latter showed slightly better agreement to the experimental data. Glass ballotini (similar to100 mum diameter) are either silanized, in order to increase their wettability toward the oil binder, or kept untreated. Results showed how the interaction between the binder and the particle influences the geometry, the capillary pressure, the force, and the rupture energy of the liquid bridge. Higher values of force and liquid bridge energy were measured between particles characterized by higher interaction (silanized-silanized configuration). A thermodynamic approach to the evaluation of the energy stored in a liquid bridge is also proposed. The mechanical work done to stretch apart the liquid bridge is evaluated as the difference of internal and hysteresis energy between the initial and the rupture configuration of the bridge. This approach showed good agreement with the experimental data only for liquid bridges formed between silanized and untreated glass particles. (C) 2003 Elsevier Science (USA). All rights reserved.