Buckling of charged diblock copolymer monolayers at the air-water interface

¹ DRECAM, Service de Physique de l'Etat Condensé, Cea-Saclay F-91191 Gif-sur-Yvette Cedex, France
² Centre de Recherche sur les Macromolécules Végétales, ICMG, FR 2607 CNRS BP 53, F-38041 Grenoble Cedex 9, France
³ LURE, CNRS/CEA/MJENR, Bâtiment 209D, Centre Universitaire Paris-Sud BP 34, F-91898 Orsay Cedex, France
⁴ DRECAM, Laboratoire Léon Brillouin, UMR CEA/CNRS, Cea-Saclay F-91191 Gif-sur-Yvette Cedex, France
⁵ Laboratoire LIONS, DRECAM/SCM, Cea-Saclay F-91191 Gif-sur-Yvette Cedex, France
⁶ Department of Chemistry, University of Tennessee, Chemical Sciences Division Oak Ridge National Laboratory - 552 Buehler Hall, Knoxville, TN 37996-1600, USA

Corresponding author: pguenoun@cea.fr

Received: 30 April 2004
Accepted: 3 March 2005

Abstract

Langmuir films of charged-neutral diblock copolymers spread at the air/water interface were studied. A reversible buckling instability of large characteristic size (10 range) is evidenced while compressing the films. A complete characterization of this phenomenon with respect to the polymer length was accomplished using optical microscopy and X-ray surface scattering. The polymer sub-phase concentration appears to control the instability threshold in surface pressure. In order to explain the observed linear variation of the buckling wavelength with the polymer mass, an analogy with the wrinkling of elastic layers is proposed.