The tip of a scanning force microscope was used to detach nanometer-scale, single crystal NaCl particles from a glass substrate under controlled atmospheres of known humidity. After characterizing a particle at low contact force, a single line scan at high contact force was used to apply stresses to the attached particle. The lateral force during the line scan showed a sharp discontinuity associated with detachment of the particle from the substrate. The peak lateral force during this procedure is a strong function of particle contact area and humidity. As the relative humidity is raised from low values, the strength of the particle-substrate bond decreases dramatically. We interpret these results in terms of detachment by chemically assisted crack growth along the NaCl-glass interface.
ASJC Scopus subject areas
- General Physics and Astronomy