Abstract
We have measured the shear viscosity in the liquid phase of several Langmuir monolayers with an accuracy better than . The method is based on the optical monitoring of the Brownian diffusion of submicron latex spheres floating at the air-water interface. The values are between 1 and , which is 10 to 100 times lower than previous data on similar systems. For -palmitoyl-6--penicillanic acid and -dipalmitoylphosphatidylcholine, the variation of the shear viscosity with surface density agrees with a classical free area model, whereas for pentadecanoic acid we observe a compensation effect.
- Received 11 January 2001
DOI:https://doi.org/10.1103/PhysRevLett.90.126104
©2003 American Physical Society