Colloidal Assembly and Separation under UV‐Induced Convective Flows and on Inclines

Kauffman, Joshua E.; Tansi, Benjamin M.; LaSalle, Christopher; Manna, Raj Kumar; Shklyaev, Oleg E.; Balazs, Anna C.; Sen, Ayusman

doi:10.1002/cnma.202100082

Cited by 3 publications

(3 citation statements)

References 27 publications

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“…Moreover, the convective fluid flow velocity is known to increase with the increasing height of the chamber. 28,29 Accordingly, we observed an increase in droplet velocity with the increasing height of the fluid in the chamber (Figure 2C).…”

Section: ■ Results and Discussionmentioning

confidence: 65%

“…Thus, for both water and PFO, the droplet velocity increased with size. The size dependence of droplet velocities can be explained by the nature of the convective flow. , Because of the no-slip boundary conditions, the fluid velocity near the bottom of the chamber increased on moving upward from the substrate (Figure C). Hence, bigger droplets experience faster fluid flow because they stick out more into the fluid.…”

Section: Resultsmentioning

confidence: 99%

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Droplet Navigation by Photothermal Pumping in an Optofluidic System

et al. 2022

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Droplets with guided motion have potential applications as microreactors and delivery vehicles. Directing long-range migration powered solely by light is particularly advantageous since light can be applied remotely, patterned with a photomask, and readily translated to irradiate specified locations. Herein, we describe a universal platform that allows fast directional navigation and collective merging of droplets controlled by either ultraviolet or visible light. The guided motion of water and oil droplets follows density-driven convective flows arising from photothermal conversion at a light-absorbing amphiphobic substrate. Because of the relatively high photothermal efficiency, a low-intensity light beam can be employed. Further, we demonstrate that the moving droplets can function as carriers and on-demand reaction chambers.

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Section: ■ Results and Discussionmentioning

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Droplet Navigation by Photothermal Pumping in an Optofluidic System

et al. 2022

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“…When these nanoparticles were irradiated at their plasmon resonance wavelength, they generated a temperature increase that led to notable fluid flow rates, reaching velocities up to 179 μm/s. Similarly, Kauffman et al 59 delved into how the photothermal properties of plasmonic nanoparticles could facilitate the movement and organization of larger microparticles via thermal convection. Both studies reported fluid velocities in the micrometers-per-second range, aligning closely with our observations.…”

Section: Numerical Validationmentioning

confidence: 99%

Thermal-Induced Convective Flow around Core–Shell Gold Nanodimers under Continuous-Wave Laser Irradiation: Implications for Nanofluidics

Fernandes,

Kang

2023

ACS Appl. Nano Mater.

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The study of heat transfer and fluid flow around gold nanostructures under laser irradiation is critical for advancements in targeted drug delivery and photothermal therapy within the field of nanofluidics. However, previous theoretical studies have predicted only nanometers-per-second flow velocities, which need to be improved for microscale mass transport. Our numerical approach investigates the thermal-induced convective flow around core–shell gold nanodimers, including nanoshells and nanorods, under continuous-wave laser irradiation using finite element modeling in the COMSOL Multiphysics package. We integrate electromagnetic, thermal, and fluid flow multiphysics simulations to quantify time-varying temperature and convective flow fields. Our study reveals that nanodimers on a substrate can generate convective flow with a velocity in the micrometers-per-second range, which is significantly higher than previous predictions. Moreover, our investigation demonstrates that thinning the metal shell in the core–shell nanodimers significantly enhances their thermofluidic response, resulting in higher temperature and flow velocity than their solid counterparts. Additionally, we report on the effects of geometrical parameters on the thermofluidic response. Our findings have significant implications for the synthesis of plasmonic nanostructures using gold as an optimized shell material for specific applications such as drug delivery. The present research not only advances our understanding of thermal-induced convective flow around gold nanodimers but also provides a robust foundation for enhancing the functionality of these nanostructures for targeted bioapplications like optical trapping in nanofluidic systems.

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Autonomous Photothermally-driven Fluid Pumping and Particle Transport and Assembly

Shklyaev

Manna

Laskar

et al. 2023

Out-of-Equilibrium Soft Matter

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We review the design of photothermally-driven fluid micropumps that can regulate the assembly and segregation of microparticles in solution. Externally imposed light represents particularly useful energy input since the light source (further enabled with a mask) is easily moved and thus can regulate spatially and temporally coordinated dynamics. Ultraviolet (UV) light sources are used to illuminate regions of a fluid-filled chamber that results in fluid flow throughout the chamber. The light-driven pumping occurs via three different mechanisms: thermal buoyancy, solutal buoyancy, and diffusioosmosis. These pumping mechanisms can operate simultaneously and the combination of two or more mechanisms leads to complex fluid flow patterns. This approach enables systems that allow dynamic control over the motion of immersed microparticles, including the formation and transport of reversible particle assemblies, as well as the segregation and separation of different sized particles in the fluidic chambers. Thus, one device can be used to both separate the particles and drive them to different locations for further processing. This property is particularly useful for analyzing fluids that contain multiple particulate types.

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Colloidal Assembly and Separation under UV‐Induced Convective Flows and on Inclines

Cited by 3 publications

References 27 publications

Droplet Navigation by Photothermal Pumping in an Optofluidic System

Droplet Navigation by Photothermal Pumping in an Optofluidic System

Thermal-Induced Convective Flow around Core–Shell Gold Nanodimers under Continuous-Wave Laser Irradiation: Implications for Nanofluidics

Autonomous Photothermally-driven Fluid Pumping and Particle Transport and Assembly

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