Eur. Phys. J. E 11, 53-59 (2003)
DOI: 10.1140/epje/i2003-10007-9

Elasticity and plasticity of two-dimensional amorphous solid layers of -lactoglobulin

S. Courty¹, B. Dollet¹, K. Kassner², A. Renault³ and F. Graner<sup>1

1</sup>  Laboratoire de Spectrométrie Physique, UMR 5588 CNRS - Université J. Fourier Grenoble 1, BP 87, F-38402 Saint Martin d'Hères cedex, France
²  Institut für Theoretische Physik, Otto-von-Guericke-Universität Magdeburg, Postfach 4120, D-39016 Magdeburg, Germany
³  Groupe Matière Condensée et Matériaux, UMR 6626 CNRS - Université Rennes 1, Campus de Beaulieu, Bât. 11A, F-35042 Rennes cedex, France

sc374@phy.cam.ac.uk
graner@ujf-grenoble.fr

(Received 10 February 2003 and Received in final form 3 April 2003 / Published online: 27 May 2003)

Abstract
We investigate the mechanical properties of a two-dimensional amorphous solid. It is formed spontaneously by the adsorption of a protein (the -lactoglobulin) at the surface of water. We measure its mechanical response in both elastic and plastic regimes by applying a point-like force (using a glass fiber). We compare our results with previous measurements of shear moduli using a floating torsion device.

PACS
68.47.Pe - Langmuir-Blodgett films on solids; polymers on surfaces; biological molecules on surfaces.
87.15.La - Biomolecules: Mechanical properties.
62.20.Dc - Elasticity, elastic constants.
62.20.Fe - Deformation and plasticity (including yield, ductility, and superplasticity).

© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003