Calculation of van der Waals interactions involving lipid vesicles

Van der Waals energies of interaction involving vesicles and lipid layers are calculated for different geometries. Results from exact and approximate calculations are compared with some existing experimental data. It is shown that sufficient accuracy can be obtained using relatively simple ‘additivity’ approximations for the contribution of dispersion interactions. A set of calculated results is presented for a small unilamellar vesicle interacting with coated and uncoated metal and polymer surfaces. A lipid coating lowers magnitude of the interaction energy approximately two-fold. The procedure gives a simple possibility to estimate Hamaker constants (and ‘Hamaker functions’) from handbook data taking into account the existing uncertainity in the materials constants of the interacting substances.