title: Calculation of the force between surfaces coated with grafted molecules by molecular simulation.
abstract: We discuss the calculation of the force between surfaces coated with anchored molecules. This force is related to the pressure and can therefore be calculated by the usual means: either by summing over all surface-particle forces or from the virial. However, we argue that the grafting of the molecule must be included by means of a restraining potential-otherwise, nonphysical results can be obtained, such as the appearance of a net force even when the particles are spaced very far away. Bond-stretching potentials are also required if the virial is employed.
authors.affiliation: Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas, Campus de la UAB, 08193 Bellaterra, Spain. dduque@icmab.es
authors.forename: Daniel
authors.initials: D
authors.lastname: Duque
authors.forename: Lourdes F
authors.initials: LF
authors.lastname: Vega