Comparison of the Resuspension Behavior Between Liquid and Solid Aerosols

Resuspension of an aerosol from solid surfaces is an important phenomenon. The resuspension behaviors of solid aerosols and liquid aerosols are not necessarily the same. A whole solid particle detaches from the surface when the removal force is sufficient, while a portion of a droplet may detach even if the removal force is insufficient to detach the whole droplet. The objective of this article is to compare the resuspension behaviors between liquid and solid aerosols from a solid surface. Polystyrene particles and glycerol in micron sizes were generated and deposited on substrates. Two types of experiments, centrifugal detachment and vibrational resuspension, were carried out. In the centrifuge experiment, a constant removal force field was provided. Larger droplets split into smaller portions during detachment. In terms of the fraction remaining, the adhesion of the liquid aerosol has the same order of magnitude to that of the solid particle. A theoretical analysis analogous to the case of pendent drop was carried out, and the theoretical prediction agreed well with the experimental result. In the vibration experiment, a sinusoidal force field was applied. A same fraction of the solid particle detached with a much smaller force in vibration experiment than in the centrifuge experiment, whereas no resuspension was observed for liquid droplets. The adhesive forces of the liquid and solid aerosols have the same order of magnitude in the centrifuge case, but in the vibration case their adhesive forces have much greater difference. It poses a necessity for further investigation.