Electrothermoplasmonic flow in gold nanoparticles suspensions: Nonlinear dependence of flow velocity on aggregate concentration.

Autor: González-Gómez CD; Universidad de Granada, Department of Applied Physics, Nanoparticles Trapping Laboratory, 18071, Granada, Spain; Universidad de Málaga, Department of Applied Physics II, 29071, Málaga, Spain., Rica RA; Universidad de Granada, Department of Applied Physics, Nanoparticles Trapping Laboratory, 18071, Granada, Spain; Universidad de Granada, Research Unit 'Modeling Nature' (MNat), 18071, Granada, Spain., Ruiz-Reina E; Universidad de Málaga, Department of Applied Physics II, 29071, Málaga, Spain; Universidad de Málaga, Department of Applied Physics II, Institute Carlos I for Theoretical and Computational Physics (iC1), 29071, Málaga, Spain. Electronic address: eruizr@uma.es.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2023 Oct 15; Vol. 648, pp. 397-405. Date of Electronic Publication: 2023 Jun 07.
DOI: 10.1016/j.jcis.2023.05.198
Abstrakt: Efficient mixing and pumping of liquids at the microscale is a technology that is still to be optimized. The combination of an AC electric field with a small temperature gradient leads to a strong electrothermal flow that can be used for multiple purposes. Combining simulations and experiments, an analysis of the performance of electrothermal flow is provided when the temperature gradient is generated by illuminating plasmonic nanoparticles in suspension with a near-resonance laser. Fluid flow is measured by tracking the velocity of fluorescent tracer microparticles in suspension as a function of the electric field, laser power, and concentration of plasmonic particles. Among other results, a non-linear relationship is found between the velocity of the fluid and particle concentration, which is justified in terms of multiple scattering-absorption events, involving aggregates of nanoparticles, that lead to enhanced absorption when the concentration is raised. Simulations provide a description of the phenomenon that is compatible with experiments and constitute a way to understand and estimate the absorption and scattering cross-sections of both dispersed particles and/or aggregates. A comparison of experiments and simulations suggests that there is some aggregation of the gold nanoparticles by forming clusters of about 2-7 particles, but no information about their structure can be obtained without further theoretical and experimental developments. This nonlinear behavior could be useful to get very high ETP velocities by inducing some controlled aggregation of the particles.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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