Entropic Trapping of Hard Spheres in Spherical Confinement
Bommineni PK, Wang J, Vogel N, Engel M (2025)
Publication Language: English
Publication Type: Journal article
Publication year: 2025
Journal
Book Volume: 134
Article Number: 198201
Journal Issue: 19
DOI: 10.1103/PhysRevLett.134.198201
Abstract
Monodisperse spherical colloidal particles confined within emulsion droplets can crystallize into icosahedral clusters. Experimentally, it was observed that a few large colloidal particles added as defects preferentially migrate to the vertices of the icosahedral clusters. To understand this structure formation phenomenon, we simulate the confined self-assembly of hard spheres in the presence of a small number of larger particles. The results demonstrate that large spheres are significantly influenced by concentric shells of small spheres near the crystallization transition. Entropic forces drive the large spheres to the cluster surface, where they settle into free energy minima at the icosahedron vertices. Notably, the addition of twelve large spheres results in the formation of a perfect icosahedral frame. Free energy calculations via umbrella sampling are used to quantify this process and show that both the migration to the cluster surface and the trapping at the vertices with trapping strength of multiple kBT results from free energy minimization. Moreover, our study reveals that the crystallization pathway and dynamics of large spheres are consistent across different systems, suggesting robustness of entropic trapping.
Authors with CRIS profile
Junwei Wang
Lehrstuhl für Interfaces und Partikeltechnologie (LFG)
Michael Engel
Lehrstuhl für Multiscale Simulation of Particulate Systems (MSS)
Involved external institutions
India (IN)How to cite
APA:
Bommineni, P.K., Wang, J., Vogel, N., & Engel, M. (2025). Entropic Trapping of Hard Spheres in Spherical Confinement. Physical Review Letters, 134(19). https://doi.org/10.1103/PhysRevLett.134.198201
MLA:
Bommineni, Praveen K., et al. "Entropic Trapping of Hard Spheres in Spherical Confinement." Physical Review Letters 134.19 (2025).
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