Issue
EPL
Volume 86, Number 3, May 2009
Article Number 36005
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/86/36005
Published online 20 May 2009
EPL, 86 (2009) 36005
DOI: 10.1209/0295-5075/86/36005

Observation of the complete rupture of a buried polymer layer by off-specular neutron reflectometry

J. P. de Silva1, S. J. Martin1, R. Cubitt2 and M. Geoghegan1

1   Department of Physics and Astronomy, University of Sheffield - Hounsfield Road, Sheffield S3 7RH, UK, EU
2   Institut Laue-Langevin - 6 rue Jules Horowitz, BP 156, F-38042 Grenoble Cédex, France, EU

j.desilva@physics.org

received 4 March 2009; accepted in final form 15 April 2009; published May 2009
published online 20 May 2009

Abstract
We have used off-specular neutron reflectometry to study the rupture of a thin, deuterated polystyrene layer confined between a silicon substrate and a thick poly(methyl methacrylate) upper layer. After total rupture of the buried layer, the resulting roughness at the interface that controls the total reflection edge gives rise to Yoneda off-specular scattering. This hypothesis is confirmed by specular reflectivity data that can be fitted to an effective error function subsequent to the rupture of the buried layer. The observed increase in the Yoneda peak intensities, integrated along the path of constant momentum transfer qz, can be directly related to the formation of an interdigitated structure upon rupture of the buried layer. A distorted-wave Born approximation is used to quantitatively simulate the form of the off-specular data in terms of an equivalent error function, with fitting parameters in good agreement with the physical properties of the samples and key experimental results.

PACS
61.05.fj - Neutron reflectometry.
68.05.-n - Liquid-liquid interfaces.
68.47.Mn - Polymer surfaces.

© EPLA 2009