Attractive and repulsive terms in multi-object dispersion interactions

Abstract: Filamentary objects such as nano-wires, nanotubes and DNA are of current interest in physics, nanoscience, chemistry, biology and medicine. They can interact via exceptionally long-ranged many-object van der Waals (vdW, dispersion) forces, causing them to cluster into multi-object bundles. We analyse their vdW interactions quantitatively, predicting $N$-object vdW energy contributions that alternate in sign with increasing $N$. We also provide novel insights permitting these tendencies to be understood simply in terms of electronic screening and anti-screening. Relevant systems include polyelectrolyte double layers, Nafion exclusion zone, endothelial surface layer of cells, microemulsion interfaces and hexagonal phases, salt fingers in Gibbs Marangoni effects, myosin fibres in muscle, multiple nanotubes in the interior of neuronal axons, and carbon fibre materials.