This project aims at studying experimentally the out of equilibrium fluctuations
in strongly confined fluids. Three main problems will be analyzed :
a) The effects on the dynamics when the fluctuations are confined in a volume smaller than the spatial correlation length; b) The fluctuations of the injected and dissipated power in out of equilibrium in highly confined systems, where extreme events may produce
an instantaneous ''negative entropy production rate''. c) Are fluctuations a limiting factor for application ? Might they be useful ?
Our strategy is to enhance the role of fluctuations and correlations working close to the critical point of a second order phase transition. We will work at the critical point
of mixing of either a binary mixture of fluids or of polymer blends, whose microscopic time scales and correlation lengths are much longer than those of binary mixtures of simple fluids. The local measurements and the confinement will be realized using an original ultra low noise Atomic Force Microscopy (AFM) developed in our laboratory. This AFM will be used in association with a near field aperture free light scattering technique, local and global dielectric techniques and evanescent waves imaging. This experimental set up, measuring local and global variables, will give new insight to two other interesting phenomena that are present in the critical regions : the finite size effects (such as dimensional crossover and time dependent critical Casimir effect) and the relaxation towards equilibrium after a quench at the critical point. These two phenomena have been widely investigated both theoretically and numerically butonly a few experiments have tried to measure directly the local fluctuations of confined fluids. Due to the universal nature of phase transitions the results can be applied to many other systems in which measurements are more complicated.
Fields of science
Call for proposal
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