Hearing bond breakage. Measurement of bond rupture forces using a quartz crystal microbalance

We present a new method of measuring bond rupture forces, It is based on the use of microparticles attached by many bonds or interactions of one type to an oscillating surface. We have used a quartz crystal microbalance and linearly increased the driving voltage resulting in bond rupture which can be detected both optically and acoustically. The rupture force spectra give sharp peaks which depend on the mass of the microparticle and the strength of the interactions attaching it to the surface. This method is applicable to weak interactions such as nonspecific adsorption through to strong chemical bonds. It has widespread potential applications in sizing, sorting, analyzing, and separations based on differences in rupture force.