title: Shear viscosity of langmuir monolayers in the low-density limit.
abstract: We have measured the shear viscosity in the liquid phase of several Langmuir monolayers with an accuracy better than 30%. 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 11x10(-10) N s m(-1), which is 10 to 100 times lower than previous data on similar systems. For N-palmitoyl-6-n-penicillanic acid and L-alpha-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.
authors.affiliation: Institut Curie, Section de Recherche, 26 rue d'Ulm, 75248 Paris CEDEX 05, France.
authors.forename: Manuel
authors.initials: M
authors.lastname: Sickert
authors.forename: Francis
authors.initials: F
authors.lastname: Rondelez