Theorie der Electrophorese -- Het Relaxatie-Effect

In this thesis, a theoretical treatment of the relation between electrophoretic velocity and the potential of the double layer of colloidal particles is presented. Translators note: The theory of electrophoresis is one of the foundational topics that underpinned the development of colloid and surface science and ranks with the famous Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. J. Th. G. Overbeek (Theo to all who knew him) was the first to develop a complete theoretical analysis of the electrophoretic motion of a charged spherical particle under the influence of an external electric field. This provided the theoretical framework for a widely used experimental method to characterize the state of charge and particle size of small colloidal particles. The solution of this problem required mastery of fluid mechanics, colloidal electrostatics, statistical thermodynamics and transport theory in addition to solid applied mathematics. Theo carried out this study as his doctoral thesis under H.R. Kruyt at Utrecht University. The thesis, in Dutch, was later published as a monograph. Given the important pedagogic value and historical status of this work, we felt that it deserved to enjoy a wide readership.