Soft Glasses and Gels - From Colloid Physics to Food Technology

Keywords:
soft glasses, colloid physics, food technology

Abstract:
Understanding the structure and dynamics of concentrated colloidal particle suspensions and gels is of enormous importance both for fundamental research as well as industrial applications. In particular aggregation and gel formation in colloidal suspensions has attracted considerable interest, and applications of sol-gel processing are used in areas as diverse as modern materials science and food technology. Considerable progress has recently been made in the understanding of how the interaction potential between colloidal particles can be tuned by adding salt, surfactants, polymers or other colloids, and how this can be used in order to tailor the resulting equilibrium phase diagrams of these complex mixtures and induce phase separation, spinodal decomposition, crystal and glass formation. In my presentation I shall demonstrate that we can for example apply concepts borrowed from classical colloid physics and materials sciences and use attraction-driven aggregation and spinodal decomposition in order to obtain nanostructured food materials with interesting and tuneable properties. However, the properties of these complex systems pose enormous challenges to experimentalists and theoreticians. An important feature is the extremely large range of characteristic length (1 – 10’000 nm) and time scales (10-9 to 10 sec) that needs to be covered in any attempt to characterize and understand their properties. Moreover, many interesting features of complex fluids are linked to the existence of non-equilibrium states and closely related to the application of external fields and variable processing conditions, which require the availability of suitable techniques for a non-invasive and in-situ characterization. Here I shall demonstrate that the combination of different scattering techniques allows us to obtain time-resolved structural and dynamic information on an extremely large range of length and time scales in a completely in-situ and non-destructive way.

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Nanotech 2005 Conference Program Abstract