Interaction of a Microsphere with a Solid-Supported Liquid Film

Abstract

The interaction between particles with thin liquid films on solid surfaces was studied by sintering polystyrene microspheres of 4 to 5 microm diameter to the end of atomic force microscope cantilevers. Films of three silicone oils (viscosity 4.6, 9.2, and 9700 mPa s) and water of thickness 0.2-1.8 microm were formed on glass. The interaction between a particle and the film was measured at different particle approach/retraction velocities. The interaction is dominated by capillary and hydrodynamic forces. It depends on the surface tension and the viscosity of the liquid. The film thickness can be determined from the force curves. In addition, the meniscus formation of a film wetting a particle was demonstrated experimentally by solidifying a liquid polystyrene film as it wetted glass particles.

Study of adhesion between microspheres and rubber surfaces accompanied by meniscus formation and sedimentation

“…The F cap portion of F meniscus , is induced by γ L at the contact line of a meniscus [14,17,23,24]:…”

“…For instance, Sharp et al [10] directly assessed the near-surface properties of polystyrene films by monitoring how gold nanoparticles became embedded. The adhesive force between spheres and substrates coated with low viscosity liquids, such as water or silicon oil, have been investigated using a capillary bridge with atomic force microscopy (AFM) [11][12][13][14]. The measured force has been fitted to a hydrodynamic force, van der Waals attraction, electrostatic repulsion, hydrodynamic drag, and the restoring force of a cantilever [11,13].…”

“…The measured force has been fitted to a hydrodynamic force, van der Waals attraction, electrostatic repulsion, hydrodynamic drag, and the restoring force of a cantilever [11,13]. In addition to these forces, Ally et al [14] has taken capillary forces into account, which has been a topic of interest among researchers for many years. Cross [15] and Pietsch [16] and their coworkers showed that the capillary force component results from the direct action of the surface free energy, with further details recently reported by Butt et al [17].…”

Application of Colloid Probe Atomic Force Microscopy to the Adhesion of Thin Films of Viscous and Viscoelastic Silicone Fluids

“…The detachment of a spherical 61 probe from thin Newtonian liquid films has been considered 62 previously using a pendulum, 33 a load cell, 34 and AFM. 35 The 63 current work builds on the previous research by considering the 64 total viscous and capillary contributions to the measured force, as 65 well as interpreting the experimental data by extending existing …”

“…11À13 Under static conditions, the adhesion arises 33 from capillary attraction while viscous forces will also be devel- 34 oped when there is relative motion between the solid surfaces. 35 Liquid bridges have been studied theoretically by numerous 36 researchers, and also experimentally often with water or another 37 Newtonian fluid. For example, atomic force microscopy (AFM) 38 has been employed widely to investigate the capillary forces, 14 in- 39 cluding the effect of humidity on condensed bridges for hydro- 40 philic and hydrophobic systems, 15À17 the critical effect of tip 41 geometry on the magnitude of the forces and the rupture 42 stability, 18,19 assessing the geometry of nanoscale contacts, 20 43 and the stability of nanoscale aqueous liquid bridges taking into 44 account possible effects arising from cavitation.…”