Particle response during the yielding transition of colloidal glasses

D. V. Denisov; M. T. Dang; B. Struth; G. H. Wegdam; P. Schall

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arXiv · 1401.2106

Particle response during the yielding transition of colloidal glasses

D. V. Denisov·M. T. Dang·B. Struth·G. H. Wegdam·P. Schall

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Abstract

Yielding is central to the relaxation, flow and fracture of a wide range of soft and molecular glasses, but its microscopic origin remains unclear. Here, we elucidate the yielding of a colloidal glass by using x-ray scattering to monitor the structure factor during the yielding process. We apply a recently introduced combination of small-angle x-ray scattering and rheology to the oscillatory shear, and follow the structure factor during the increasing strain amplitude. Surprisingly, we observe a sharp transition in the orientational ordering of the nearest-neighbor structure upon yielding, in contrast to the smooth variation of the viscoelastic moduli. This transition is accompanied by a sudden change of intensity fluctuations towards Gaussian distributions. We thus identify yielding as a new, dynamically induced transition of the glass in response to the applied shear.

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D. V. Denisov, M. T. Dang, B. Struth, G. H. Wegdam, P. Schall. 2014-01-09. Particle response during the yielding transition of colloidal glasses. https://arxiv.org/abs/1401.2106

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