Please use this identifier to cite or link to this item: http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/4680
Title: Large-scale optothermal assembly of colloids mediated by a gold microplate
Authors: SHARMA, VANDANA
PAUL, DIPTABRATA
CHAUBEY, SHAILENDRA K.
TIWARI, SUNNY
KUMAR, G. V. PAVAN
Dept. of Physics
Keywords: Thermophoresis
Optothermal
Colloidal Assembly
Voronoi Decomposition
Gold Microplate
TOC-JUN-2020
2020
2020-JUN-WEEK2
Issue Date: Jul-2020
Publisher: IOP Publishing
Citation: Journal of Physics-Condensed Matter, 32(32).
Abstract: Light-activated colloidal assembly and swarming can act as model systems to explore non-equilibrium state of matter. In this context, creating new experimental platforms to facilitate and control two-dimensional assembly of colloidal crystals are of contemporary interest. In this paper, we present an experimental study of assembly of colloidal silica microparticles in the vicinity of a single-crystalline gold microplate evanescently excited by a 532 nm laser beam. The gold microplate acts as a source of heat and establishes a thermal gradient in the system. The created optothermal potential assembles colloids to form a two-dimensional poly-crystal, and we quantify the coordination number and hexagonal packing order of the assembly in such a driven system. Our experimental investigation shows that for a given particle size, the variation in assembly can be tuned as a function of excitation-polarization and surface to volume ratio of the gold microplates. Furthermore, we observe that the assembly is dependent on size of the particle and its material composition. Specifically, silica colloids assemble but polystyrene colloids do not, indicating an intricate behaviour of the forces under play. Our work highlights a promising direction in utilizing metallic microstructures that can be harnessed for optothermal colloidal crystal assembly and swarming studies. Our experimental system can be utilized to explore optically driven matter and photophoretic interactions in soft-matter including biological systems such as cells and micro organisms.
URI: http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/4680
https://doi.org/10.1088/1361-648X/ab8552
ISSN: 0953-8984
1361-648X
Appears in Collections:JOURNAL ARTICLES

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