Discriminating stochastic processes for the assessment of materials properties by diffusion measurements

DOI zum Zitieren der Version auf EPub Bayreuth: https://doi.org/10.15495/EPub_UBT_00009356
URN to cite this document: urn:nbn:de:bvb:703-epub-9356-2

Title data

Metzler, Ralf ; Weiss, Matthias:
Discriminating stochastic processes for the assessment of materials properties by diffusion measurements.
In: Physical Chemistry Chemical Physics. Vol. 27 (June 2025) . - pp. 14350-14358.
ISSN 1463-9084
DOI der Verlagsversion: https://doi.org/10.1039/D5CP01378J

	Format: PDF Name: d5cp01378j.pdf Version: Published Version Available under License Creative Commons BY 3.0: Attribution
	Download (1MB)

Project information

Project title:	Project's official title Project's id Open Access Publizieren No information

Abstract

Assessing the materials properties of complex media, e.g. colloidal suspensions or intracellular fluids, frequently relies on quantifying the diffusive motion of tracer particles. In particular, from the particles’ mean squared displacement (MSD) one may infer the complex shear modulus of the medium. Yet, experimentally the same power-law forms of the MSDs emerge for tracer diffusion in very different environments. For example, diffusive motion in a static maze of fractal obstacles (obstructed diffusion, OD) and motion in viscoelastic fluids (often described by fractional Brownian motion, FBM) can show an identical sublinear MSD scaling, but an MSD-derived complex shear modulus is meaningless for OD as the system does not feature any viscoelasticity. Here we show that OD and FBM trajectories are highly similar in many observables, including the MSD and the autocovariance function that reports on the memory of the particle motion. The Gaussianity and/or the asphericity of trajectories, extracted with single-particle tracking, allows for a proper discrimination of OD and FBM, facilitating a meaningful interpretation of the materials properties of the medium. In contrast, techniques that only monitor particle number fluctuations in a region of interest are not capable of discriminating highly similar random processes like FBM and OD as they only rely on the MSD. We therefore highly recommend the use of the more informative tracking of single particles when aiming to asses materials properties of the medium under investigation.

Further data

Item Type:	Article in a journal
DDC Subjects:	500 Science > 530 Physics 500 Science > 570 Life sciences, biology
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics I - Physics of Living Matter > Chair Experimental Physics I - Physics of Living Matter - Univ.-Prof. Dr. Matthias Weiss Faculties Faculties > Faculty of Mathematics, Physics und Computer Science Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics I - Physics of Living Matter
Language:	English
Originates at UBT:	Yes
URN:	urn:nbn:de:bvb:703-epub-9356-2
Date Deposited:	28 May 2026 10:46
Last Modified:	28 May 2026 10:46
URI:	https://epub.uni-bayreuth.de/id/eprint/9356

Download Statistics

Download Statistics

Download Statistics

Downloads

Downloads per month over past year