8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.3Two-dimensional microrheology of Langmuir polymerfilmsMaestro Armando, 1 Ortega Francisco, 2 and Rubio Ramon 21 laboratoire de Physique des Solides. Université Paris Sud 11, UMR 8502, Bat. 510,Orsay 91405 cedex, France, 91405, Orsay, France2 Departamento de Química Física I, Universidad Complutense de Madrid, Madrid,SpainInterfaces play a dominant role in the behavior of many complex fluids. Interfacial rheology hasbeen found to be a key factor in the stability of foams and emulsions, compatibilization of polymerblends, flotation technology, fusion of vesicles, etc. Particle-laden interfaces have attracted muchattention in recent years. The tendency of colloidal microparticles to become (almost irreversibly)trapped at interfaces and their behavior once there, has lead to their use in a wide variety of systemsincluding drug delivery, stabilization of foams and emulsions, froth, flotation, or ice cream production.The high trapping energy of particles at interfaces provides a route to use fluid interfaces asa substrate for the self-assembly of particles into materials of specific mechanical, optical or magneticproperties. A new rheological methodology has emerged that probes the material responseon micrometer length scales. Microrheology is a term that does not describe one particular technique,but rather a number of approaches that attempt to overcome some limitations of traditionalbulk rheology. Microrheology methods typically use embedded micron-sized probes to locallydeform the sample, permitting the use of very small volumes (∼ l). The aim of the present workis to briefly demonstrate the validity of the experimental techniques applied to interface dynamicsbased on the video-analysis the Brownian motion of particles tracers attached at the fluid interface.We will summarize the available theoretical models for calculating the shear viscoelastic complexmoduli of polymer Langmuir monolayers from particle tracking experiments.3