A scanning force microscope study of detachment of nanometer-sized particles from glass surfaces

The nominal shear stress required to detach nanometer-scale, single-crystal salt particles from a soda lime glass substrate is a strong function of pa rticle size and relative humidity. We use the tip of an atomic force micros cope to detach these particles from a glass substrate under controlled atmo spheres of known humidity. The peak lateral force at detachment was divided by the nominal particle area to yield an effective interfacial shear stren gth. We describe the variation of shear strength with particle area and hum idity in terms of detachment by chemically assisted crack growth along the salt-glass interface.