A tangential force model for interactions between bonded colloidal particles

Recently, Pantina and Furst (Phys. Rev. Lett., 94(13), 138301, 2005) experimentally demon- strated that there are tangential forces between bonded colloidal particles and that bonds between colloidal particles are capable of supporting bending moments. We introduce a model to be used in computer simulations that describes these tangential interactions. We show how the model parame- ters can be determined from experimental data. Simulations using the model are able to reproduce the measurement of Pantina and Furst. Application of the model to an aggregate with fractal structure leads to more realistic behavior than using classical approaches only.