Effect of surface mobility on the particle sliding along a bubble or a solid sphere

Area of Science:

• Colloid and Surface Science
• Physics of Soft Matter
• Particle Dynamics

Background:

• Understanding particle-surface interactions is crucial in various industrial and natural processes.
• The role of surface mobility in dictating particle motion dynamics remains an area of active investigation.

Purpose of the Study:

• To investigate the effect of surface mobility on the sliding velocity of glass beads on spherical surfaces.
• To analyze the influence of bubble surface mobility versus rigid surfaces on particle dynamics.
• To establish relationships governing particle sticking and sliding behaviors.

Main Methods:

• Experimental measurement of glass bead sliding velocity on stationary glass spheres and air bubbles.
• Digital camera recording and frame-by-frame analysis of the sliding process.
• Application and modification of Stokes equation to describe sliding velocity, fitting experimental data.

Main Results:

• Glass beads accelerate on collector surfaces, reaching maximum velocity around 100 degrees.
• Sliding velocity is strongly dependent on surface mobility, decreasing with reduced mobility.
• Sliding velocity on rigid surfaces is significantly lower than on mobile bubble surfaces.
• A critical sticking angle was observed for hydrophobic beads on hydrophobic surfaces, linked to capillary forces.

Conclusions:

• Surface mobility is a key factor controlling particle sliding velocity.
• A modified Stokes equation effectively describes the observed sliding behavior.
• Capillary forces and surface properties dictate particle adhesion and sticking phenomena.