LONDON – VAN DER WAALS ATTRACTIVE FORCES BETWEEN GLASS SURFACES

Abstract

The attractive force between a pyrex glass bead and plate has been measured using a sensitive pendulum-type apparatus. The force required for separation of the bead from the plate has been shown to be strongly time dependent, a phenomenon which appears not to have been reported previously for adhesions in gaseous media. The observed results have been shown to be consistent with the theoretical London – van der Waals interaction. The estimated value of the London force constant is compared with that obtained by other workers.