A study of adhesion forces by atomic force microscopy

An atomic force microscope (AFM) was used to investigate Si3N4 tip interact ions with various materials in four different liquid media (water, ethanol, ethylene glycol, and formamide). The adhesion forces calculated using surf ace energies and the values measured experimentally were compared. For all materials, the calculated adhesion force closely correlated with AFM measur ements, except in water. In the case of water, the AFM experiments showed s trong adhesion. whereas theoretically (van Oss-Chaudhury-Good model) repuls ion is predicted. The difference observed is discussed in terms of the chem ical interactions between Si3N4 and water.