Elastic and Dynamic Heterogeneity in Aging Alginate Gels.

Anomalous aging in soft glassy materials has generated a great deal of interest because of some intriguing features of the underlying relaxation process, including the emergence of "ultra-long-range" dynamical correlations. An intriguing possibility is that such a huge correlation length is reflected in detectable ensemble fluctuations of the macroscopic material properties. We tackle this issue by performing replicated mechanical and dynamic light scattering (DLS) experiments on alginate gels, which recently emerged as a good model-system of anomalous aging.

Analysis of the aging effects on the viscoelasticity of alginate gels.

The effect of aging on the mechanical behaviour of ionically cross-linked alginate gels is studied in detail. Relaxation experiments upon both unconfined compression and torsion are performed on samples at different aging times. The elastic moduli of the gel are found to increase with the aging time, whereas the internal (constitutive) mechanism of the relaxation of the solid component of the gel is found to be unaffected by aging.

Analysis of linear viscoelastic behaviour of alginate gels: effects of inner relaxation, water diffusion, and syneresis.

The mechanical behaviour of ionically cross-linked alginate gels is investigated here in detail. To determine the range of linear response of the materials, uniaxial, unconfined compression and torsional deformation experiments are performed, obtaining both the stress-strain and the viscoelastic behaviour of the gels. On-line measurements of the radii of the cylindrical gel samples in these experiments are also reported.