Europhys. Lett.
Volume 68, Number 1, October 2004
Page(s) 65 - 71
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 September 2004
Europhys. Lett., 68 (1), pp. 65-71 (2004)
DOI: 10.1209/epl/i2004-10166-9

Scaling of dynamics in 2d semi-dilute polymer solutions

P. Cicuta1 and I. Hopkinson2

1  Cavendish Laboratory, University of Cambridge Madingley Road, Cambridge CB3 0HE, UK
2  Department of Physics, UMIST - Manchester M60 1QD, UK

received 24 May 2004; accepted in final form 29 July 2004

We consider the dynamics of thermal concentration fluctuations in polymer Langmuir monolayers, probed with surface light scattering. We present data on the proteins $\beta$-lactoglobulin and $\beta$-casein and on the synthetic polymers Poly(vinyl acetate) and Poly(4-hydroxystyrene). We show that for all these systems, in the semi-dilute concentration regime, there is a power law dependency of both the elastic and viscous components of the dilational modulus on the concentration. We find that for all the systems considered, the viscosity scales with a power that is double that of the elasticity. A simple explanation for this universal dynamical behavior in semidilute polymer monolayers is suggested.

68.03.Cd - Surface tension and related phenomena.
83.85.Ei - Optical methods; rheo-optics.

© EDP Sciences 2004