Dresden 2006 – wissenschaftliches Programm

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SYNP: Nonequilibrium Phenomena in Soft Condensed Matter

SYNP 2: Noneqilibrium Phenomena in Soft Condensed Matter

SYNP 2.3: Hauptvortrag

Dienstag, 28. März 2006, 12:00–12:30, HSZ 04

Equilibrium and non-equilibrium phenomena in complex food systems — •Raffaele Mezzenga — University of Fribourg and Nestlé Research Center, Switzerland

Complex food systems, as any other soft-condensed matter material, exhibit a behaviour, whose thermodynamic nature is intimately related to the relevant length scale considered. Since foods are structured over a broad range of different typical length scales, very different kinetics to attain their equilibrium configuration are encountered. If correlation length scales are small, very short times are needed to re-organize molecules to attain equilibrium, while if correlation length scales are large, very slow kinetics will be followed. This explains why, for examples, foams, where length scales reach the order of millimeters, can be stable for long times despite their high internal energy associated with the presence of very large interfaces, whereas self-assembled liquid crystalline foods, whose typical feature size is of the order of few nanometers, are almost always observed at the equilibrium. In the present talk we consider a few selected examples of foods in which the equilibrium/non equilibrium nature can be directly related to the typical length scale of the structure and we will discuss the current understanding of the physics ruling their macroscopic behaviour.