Eur. Phys. J. B 3, 211-216 (1998)
https://doi.org/10.1007/s100510050305

Anomalous adhesion in adsorbed polymer layers

¹ Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
² Institut Charles Sadron (CNRS UPR 22) and University Louis Pasteur, 6 rue Boussingault, 67083 Strasbourg Cedex, France
³ Laboratoire de Chimie et de Physicochimie des Assemblages Supramoléculaires Organisés (CNRS URA 448) , Institut Curie, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France

Corresponding author: ^a Jean-Marc.DiMeglio@ics.u-strasbg.fr

Received: 12 November 1997
Accepted: 6 March 1998
Published online: 15 May 1998

Abstract

Anomalous adhesion behaviour observed in the polydimethylsiloxane/heptane/silica system is reported. This behaviour is characterised by the infrequent appearance of one or more elastic minima which occur in addition to the ever-present primary adhesion. The resulting elastic force is attributed to loops connecting the tip to the substrate and can be described by two models; a worm-like chain, and a freely jointed chain. Both models give similar values for the characteristic segment length of around 0.24 nm and indicate that the chains have been extended by between 90 to 95% of their chain contour length before desorption. In some cases multiple adhesions were observed between tip and substrate and have been used to suggest a method for determining the distribution of adsorbed polymer loops.