The fragile-to-strong dynamical crossover and the system viscoelasticity in attractive glass forming colloids
Author(s)
Mallamace, Francesco; Corsaro, C.; Mallamace, D.; Chen, Sow-Hsin
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The dynamical arrest phenomena of an adhesive hard-sphere (AHS) colloid, L64-D 2O system has been studied by using calorimetry and the complex shear modulus. This system is characterized by a rich temperature (T) and volume fraction (ϕ) phase diagram with a percolation line (PT). According to the mode-coupling theory (MCT), a cusp-like singularity and two glassy phases, one attractive (AG) and one repulsive (RG), are supposed to coexist in the phase diagram. The MCT scaling laws used to study the shear viscosity with ϕ and T as control parameters propose the existence of fragile-to-strong dynamic crossover (FSDC) analogous to that observed in molecular supercooled liquid glass formers. The measured critical values of the control parameters, coincident with the PT line, where the clustering process generates the AG phase, define the FSDC locus. This is in agreement with the extended mode-coupling theory that takes into account both cage and inter-cluster hopping effects. In this work, we demonstrate, by considering the frequency dependence of the complex moduli, that there is the onset of a system viscoelasticity as an effect of the clustering accompanying the FSDC. We will show as the measured frequency-dependent complex moduli satisfy the scaling relations predicted by the scalar elasticity percolation theory and well account for the system evolution toward the glass transition process.
Description
This paper is dedicated to Professor Heinz Hoffmann on the occasion of his 80th birthday in celebration of his long-time friendship with both of us (Professors Sow-Hsin Chen and Francesco Mallamace).
Date issued
2015-08Department
Massachusetts Institute of Technology. Department of Nuclear Science and EngineeringJournal
Colloid and Polymer Science
Publisher
Springer Berlin Heidelberg
Citation
Mallamace, F., C. Corsaro, D. Mallamace, and S.-H. Chen. “The Fragile-to-Strong Dynamical Crossover and the System Viscoelasticity in Attractive Glass Forming Colloids.” Colloid and Polymer Science 293:11 (August 15, 2015), pp.3337–3349.
Version: Author's final manuscript
ISSN
0303-402X
1435-1536