Dresden 2020 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Active Matter IV (joint session DY/BP/CPP)

BP 24.3: Talk

Wednesday, March 18, 2020, 10:30–10:45, ZEU 160

Probing mechanical properties of rod-shaped colloidal suspensions with active particles — •N Narinder and Clemens Bechinger — Fachbereich Physik, Universität Konstanz, Konstanz, Germany

Recently self-propelled colloidal particles have been shown to provide a novel tool to probe the mechanical properties of colloidal glassy states of spherical particles [1]. Unlike conventional micro-rheology, where one studies the coupling between the translational motion of a driven probe particle to a background, here the coupling of the host medium to the rotational dynamics of the self-propelled particle contains information about the mechanical properties of the host medium. Here, we apply this method to study the mechanical properties of assemblies of rod-shaped particles with a mean aspect ratio of 15. Such anisotropic colloidal suspensions exhibit a rather rich phase behavior including a two-step glass transition at the aspect ratio considered here [2]. Our first results demonstrate a strong variation of the rotational dynamics of the active particle with increasing area fraction of the rods.

[1] C. Lozano, J.R. Gomez-Solano, & C. Bechinger Nature Materials 18, 1118-1123 (2019).

[2] Z. Zheng, F. Wang, & Y. Han PRL 107, 065702 (2011).