Study of dynamic effects in microparticle adhesion using Atomic force microscopy

Abstract

The adhesion and removal of particles from surfaces is a contemporary problem in many industrial applications like Semiconductor manufacturing, Bioaerosol removal, Pharmaceuticals, Adhesives and Petroleum industry. The complexity of the problem is due to the variety of factors like roughness, temperature, humidity, fluid medium etc. that affect pull-off of particles from surfaces. In particle removal from surfaces using fluid motion, the dynamic effects of particle separation will play an important role. Thus it is essential to study the dynamic effects of particle removal. Velocity of pull-off and force duration effects are two important dynamic factors that might affect pull-off. Particle adhesion studies can be made using the Atomic Force Microscope (AFM). The velocity of pull-off and force duration can be varied while making the AFM measurements. The objective of the current work is to obtain the dependence of pull-off force on pull-off velocity. Experiments were conducted using AFM and the data obtained from the experiments is processed to obtain plots for pull-off force vs. particle size and pull-off force vs. pull-off velocity. The pull-off force is compared with the predictions of previous contact adhesion theories. A velocity effect on pull-off force is observed from the experiments conducted.