Direct observation of impact propagation and absorption in dense colloidal monolayers

Open access
Date
2017-11-14Type
- Journal Article
Citations
Cited 18 times in
Web of Science
Cited 18 times in
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ETH Bibliography
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Abstract
Dense colloidal suspensions can propagate and absorb large mechanical stresses, including impacts and shocks. The wave transport stems from the delicate interplay between the spatial arrangement of the structural units and solvent-mediated effects. For dynamic microscopic systems, elastic deformations of the colloids are usually disregarded due to the damping imposed by the surrounding fluid. Here, we study the propagation of localized mechanical pulses in aqueous monolayers of micron-sized particles of controlled microstructure. We generate extreme localized deformation rates by exciting a target particle via pulsed-laser ablation. In crystalline monolayers, stress propagation fronts take place, where fast-moving particles (V approximately a few meters per second) are aligned along the symmetry axes of the lattice. Conversely, more viscous solvents and disordered structures lead to faster and isotropic energy absorption. Our results demonstrate the accessibility of a regime where elastic collisions also become relevant for suspensions of microscopic particles, behaving as “billiard balls” in a liquid, in analogy with regular packings of macroscopic spheres. We furthermore quantify the scattering of an impact as a function of the local structural disorder. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000213304Publication status
publishedExternal links
Journal / series
Proceedings of the National Academy of Sciences of the United States of AmericaVolume
Pages / Article No.
Publisher
National Academy of SciencesSubject
colloidal crystals; wave propagation; impact absorption; elastohydrodynamics; laser ablationOrganisational unit
09455 - Isa, Lucio / Isa, Lucio
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Show all metadata
Citations
Cited 18 times in
Web of Science
Cited 18 times in
Scopus
ETH Bibliography
yes
Altmetrics