Hierarchical cross-linking in physical alginate gels: a rheological and dynamic light scattering investigation

Abstract

We investigate the dynamics of alginate gels, an important class of biopolymer-based viscoelastic materials, by combining mechanical tests and non-conventional, time-resolved light scattering methods. Two relaxation modes are observed upon applying a compressive or shear stress. Dynamic light scattering and diffusive wave spectroscopy measurements reveal that these modes are associated with discontinuous rearrangement events that restructure the gel network via anomalous, non-diffusive microscopic dynamics. We show that these dynamics are due to both thermal activation and internal stress stored during gelation and propose a scenario where a hierarchy of cross-links with different life times is responsible for the observed complex behavior. Measurements at various temperatures and sample ages are presented to support this scenario.

To appear in Soft Matter

References in corpus (4)

• Length scale dependence of dynamical heterogeneity in a colloidal fractal gel
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• Resolving long-range spatial correlations in jammed colloidal systems using photon correlation imaging
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Cited by in corpus (1)

• A novel setup coupling space-resolved dynamic light scattering and rheometetry unveils the heterogeneous flow field and non-affine dynamics in startup shear of a gel