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

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

Corresponding author: j.desilva@physics.org

Received: 4 March 2009
Accepted: 15 April 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 q_z, 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.