Differential dynamic microscopy microrheology of soft materials: A tracking-free determination of the frequency-dependent loss and storage moduli
Articolo
Data di Pubblicazione:
2017
Citazione:
Differential dynamic microscopy microrheology of soft materials: A tracking-free determination of the frequency-dependent loss and storage moduli / P. Edera, D. Bergamini, V. Trappe, F. Giavazzi, R. Cerbino. - In: PHYSICAL REVIEW MATERIALS. - ISSN 2475-9953. - 1:7(2017 Dec 29), pp. 073804.1-073804.11. [10.1103/PhysRevMaterials.1.073804]
Abstract:
Particle-tracking microrheology (PT-mu r) exploits the thermal motion of embedded particles to probe the local mechanical properties of soft materials. Despite its appealing conceptual simplicity, PT-mu r requires calibration procedures and operating assumptions that constitute a practical barrier to its wider application. Here we demonstrate differential dynamic microscopy microrheology (DDM-mu r), a tracking-free approach based on the multiscale, temporal correlation study of the image intensity fluctuations that are observed in microscopy experiments as a consequence of the translational and rotational motion of the tracers. We show that the mechanical moduli of an arbitrary sample are determined correctly over a wide frequency range provided that the standard DDM analysis is reinforced with an iterative, self-consistent procedure that fully exploits the multiscale information made available by DDM. Our approach to DDM-mu r does not require any prior calibration, is in agreement with both traditional rheology and diffusing wave spectroscopy microrheology, and works in conditions where PT-mu r fails, providing thus an operationally simple, calibration-free probe of soft materials.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Complex fluids; particle tracking; colloidal dynamics; light-scattering; diffusion; gels; viscosity; water
Elenco autori:
P. Edera, D. Bergamini, V. Trappe, F. Giavazzi, R. Cerbino
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