1. Accessing the Free Expansion of a Crystalline Colloidal Drop by Optical Experiments
- Author
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Witt, Marcus, Nguyen, G. H. Philipp, von Puttkamer-Luerssen, Josefine R., Yilderim, Can H., Wagner, Johannes A. B., Malek, Ebrahim, Juretzka, Sabrina, Meyrelles Jr., Jorge L., Hofmann, Maximilan, Löwen, Hartmut, and Palberg, Thomas
- Subjects
Condensed Matter - Soft Condensed Matter - 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., Comment: Thoroughly revised version. now 23 pages with 9 figures and 57 references; supplementary materials 15 pages with 11 figures and 22 references. Accepted for publication in Soft Matter in August 2024
- Published
- 2024