Eur. Phys. J. B 1, 233-244 (1998)
https://doi.org/10.1007/s100510050177

Adsorption and spreading of polymers at plane interfaces; theory and molecular dynamics simulations

¹ Wageningen Agricultural University, Laboratory for Physical Chemistry and Colloid Science, Dreijenplein 6, 6703 HB Wageningen, The Netherlands
² University of Mons-Hainaut, Research Centre for Molecular Modelling, 20 Place du Parc, 7000 Mons, Belgium

Corresponding author: ^a mars@fenk.wau.nl

Received: 18 July 1997
Revised: 27 October 1997
Accepted: 6 November 1997
Published online: 15 January 1998

Abstract

Nonequilibrium processes play a key role in the adsorption kinetics of macromolecules. It is expected that the competition between transport of polymer towards an interface and its subsequent spreading has a significant influence on the adsorbed amount. An increase of the transport rate can lead to an increase of the adsorbed amount, especially when the polymer has too little time to spread at the interface. In this study we present both molecular dynamics simulations and analytical calculations to describe some aspects of the adsorption kinetics. From MD simulations on a poly(ethylene oxide) chain in vacuum near a graphite surface, we conclude that the spreading process can, in first approximation, be described by either a simple exponential function or by first-order reaction kinetics. Combining these spreading models with the transport equations for two different geometries (stagnation-point flow and overflowing cylinder) we are able to derive analytical equations for the adsorption kinetics of polymers at solid–liquid and at liquid–fluid interfaces.