Electro-Thermo-Plasmonic Flow in Gold Nanoparticle Suspensions: Nonlinear Flow Velocity Dependence with Aggregates Concentration

Fuente: arXiv
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Main Authors: Gómez, Carlos David González, Rica, Raúl A., Ruiz-Reina, Emilio
Format: Preprint
Published: 2022
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author Gómez, Carlos David González
Rica, Raúl A.
Ruiz-Reina, Emilio
author_facet Gómez, Carlos David González
Rica, Raúl A.
Ruiz-Reina, Emilio
contents 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 electro-thermal flow that can be used for multiple purposes. Combining simulations and experiments, an analysis of the performance of electro-thermal flow is provided when the temperature gradient is generated by illuminating plasmonic nanoparticles in suspension with a near-resonance focused 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 and individual particles, 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 dispersed particles and/or aggregates. A comparison of experiments and simulations suggests that the gold nanoparticles are aggregated forming clusters of about 5-9 particles, but no information about their structure cannot 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.
format Preprint
id arxiv_https___arxiv_org_abs_2212_14483
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Electro-Thermo-Plasmonic Flow in Gold Nanoparticle Suspensions: Nonlinear Flow Velocity Dependence with Aggregates Concentration
Gómez, Carlos David González
Rica, Raúl A.
Ruiz-Reina, Emilio
Fluid Dynamics
Mesoscale and Nanoscale Physics
Applied Physics
Optics
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 electro-thermal flow that can be used for multiple purposes. Combining simulations and experiments, an analysis of the performance of electro-thermal flow is provided when the temperature gradient is generated by illuminating plasmonic nanoparticles in suspension with a near-resonance focused 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 and individual particles, 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 dispersed particles and/or aggregates. A comparison of experiments and simulations suggests that the gold nanoparticles are aggregated forming clusters of about 5-9 particles, but no information about their structure cannot 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.
title Electro-Thermo-Plasmonic Flow in Gold Nanoparticle Suspensions: Nonlinear Flow Velocity Dependence with Aggregates Concentration
topic Fluid Dynamics
Mesoscale and Nanoscale Physics
Applied Physics
Optics
url https://arxiv.org/abs/2212.14483