The dynamics of the annihilation of point defects in Langmuir monolayers were studied. The absence of hydrodynamic effects permitted the asymmetry in defect mobility to be quantitatively related to the elastic anisotropy of the material which, in turn, could be varied via control of the surface pressure applied to the monolayer. By using this theoretical analysis, it was possible to obtain elusive equilibrium properties from relatively simple dynamic measurements. In particular, the elastic constants and their pressure dependences were measured.

Probing Elastic Anisotropy from Defect Dynamics in Langmuir Monolayers. J.Brugués, J.Ignés-Mullol, J.Casademunt, F.Sagués: Physical Review Letters, 2008, 100[3], 037801