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arXiv · 2404.07642

Accessing the Free Expansion of a Crystalline Colloidal Drop by Optical Experiments

Marcus Witt·G. H. Philipp Nguyen·Josefine R. von Puttkamer-Luerssen·Can H. Yilderim·Johannes A. B. Wagner·Ebrahim Malek·Sabrina Juretzka·Jorge L. Meyrelles Jr.·Maximilan Hofmann·Hartmut Löwen·Thomas Palberg
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Abstract

We study poly-crystalline spherical drops of an aqueous suspension of highly charged colloidal spheres exposed to a colloid-free aqueous environment. Crystal contours were obtained from standard optical imaging. The crystal spheres first expand to nearly four times their initial volume before slowly shrinking due to dilution-induced melting. Exploiting coherent multiple-scattering by (110) Bragg reflecting crystals, time-dependent density profiles were recorded deep within the drop interior. These show a continuously flattening radial density gradient and a decreasing central density. Expansion curves and density profiles are qualitatively consistent with theoretical expectations based on dynamical density functional theory for the expansion of a spherical crystallite made of charged Brownian spheres. We anticipate that our study opens novel experimental access to densi-ty determination in turbid crystals.

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Marcus Witt, G. H. Philipp Nguyen, Josefine R. von Puttkamer-Luerssen, Can H. Yilderim, Johannes A. B. Wagner, Ebrahim Malek, Sabrina Juretzka, Jorge L. Meyrelles Jr., Maximilan Hofmann, Hartmut Löwen, Thomas Palberg. 2024-04-11. Accessing the Free Expansion of a Crystalline Colloidal Drop by Optical Experiments. https://arxiv.org/abs/2404.07642

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