Accessing the Free Expansion of a Crystalline Colloidal Drop by Optical Experiments
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.
Keywords
Cite
@article{arxiv.2404.07642,
title = {Accessing the Free Expansion of a Crystalline Colloidal Drop by Optical Experiments},
author = {Marcus Witt and G. H. Philipp Nguyen and Josefine R. von Puttkamer-Luerssen and Can H. Yilderim and Johannes A. B. Wagner and Ebrahim Malek and Sabrina Juretzka and Jorge L. Meyrelles and Maximilan Hofmann and Hartmut Löwen and Thomas Palberg},
journal= {arXiv preprint arXiv:2404.07642},
year = {2024}
}
Comments
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