Europhys. Lett., 64 (5) , pp. 709-715 (2003)
Two-dimensional shear modulus of a Langmuir foamS. Courty1, B. Dollet1, F. Elias2, P. Heinig3 and F. Graner1
1 Laboratoire de Spectrométrie Physique (UMR 5588 CNRS, Université J. Fourier Grenoble 1) BP 87, F-38402 Saint Martin d'Hères cedex, France
2 Laboratoire des Milieux Désordonnés et Hétérogènes (UMR 7603 CNRS, Université Paris 6) case 78, 4 place Jussieu, F-75252 Paris cedex 05, France
3 Max Planck Institut of Colloids and Interfaces Am Mühlenberg 1, D-14476 Golm, Germany
(Received 13 May 2003; accepted in final form 16 September 2003)
We deform a two-dimensional (2D) foam, created in a Langmuir monolayer, by applying a mechanical perturbation, and simultaneously image it by Brewster-angle microscopy. We determine the foam stress tensor (through a determination of the 2D gas-liquid line tension, ) and the statistical strain tensor, by analyzing the images of the deformed structure. We deduce the 2D shear modulus of the foam, . The foam effective rigidity is predicted to be , which agrees with the value obtained in an independent mechanical measurement.
83.80.Iz - Emulsions and foams.
68.18.-g - Langmuir-Blodgett films on liquids.
62.20.Dc - Elasticity, elastic constants.
© EDP Sciences 2003