On the calculation of the van der Waals attraction between latex particles

Abstract The van der Waals attraction between uncharged, spherical polymeric latex particles in both aqueous and non-aqueous dispersion media has been calculated using the quantum field theory approach due to Lifshitz and Ninham and Parsegian. It is shown that for close approach it is possible to define a Hamaker function, analogous to the classical Hamaker constant, that is a function of the ratio (δ) of the minimum distance of surface separation to the particle radius. Computations for polymer latex particles in water showed that the Hamaker function for close approach decreases linearly with δ. However for polymers in hydrocarbons, the Hamaker functions are in fact constant. Both results are also derived analytically. A major obstacle to accurate calculations using this approach is the difficulty of converting the readily available gaseous ionization potentials into values for solids and liquids by providing due allowance for the polarization energy of the dielectric medium.