Numerical Calculation of London-van der Waals Adhesion Force Distributions for Different Superquadric Shaped Particles

摘要

The macroscopic behavior of dry submicron particle systems,for example the flowability,the agglomeration behavior and the dispersing properties,is influenced decisively by the London-van der Waals dispersion force.Knowledge of expectable interparticular dispersion forces could be useful to characterize applications in practice,regarding e.g.process parameters,product quality,environmental and industrial safety.In this paper a basic method for forecasting interparticular dispersion forces is introduced.One method to obtain information about the dispersion forces is to start by analyzing a single particle of a given shape in a certain system,and consider the particle-wall system for which the dispersion force distribution is calculated.The distribution describes the resulting calculated adhesive forces when pairing the particle with a semi-infinite wall surface in all of the possible positions,assuming a constant surface distance is maintained.Additionally,it is shown that the knowledge of the particle projection screen shape in many cases is sufficient to calculate the force distribution for the associated 3D particle.Thereby,calculation of the dispersion forces for moderate sized (radius < 30 nm) two- and three-dimensional particles represents no great difficulty,but rather the challenge is the allocation of the 2D to the 3D data.The aim is to reduce the time and effort spent on calculation in order to establish a basis for later dispersion force calculations of bigger particles and particle collectives.