Marangoni convection in an evaporating water droplet

Kazemi, Mohammad Amin; Saber, Sepehr; Elliott, Janet A.W.; Nobes, David S.

doi:10.1016/j.ijheatmasstransfer.2021.122042

Cited by 23 publications

(9 citation statements)

References 51 publications

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“…Oil‐based ferrofluids typically exhibit a strong photothermal Marangoni convection when exposed to a laser beam, [ 15,33 ] while water‐based composite fluids display weak photothermal surface deformation and Marangoni flow under similar magnetic field conditions. [ 36 ] Based on these observations, we hypothesize that the observed thermomagnetic convection is specifically related to the intrinsic physical properties of water‐based ferrofluids. To support this assumption and validate the existence of thermomagnetic convection, we utilize a simplified computational fluid dynamics model using COMSOL.…”

Section: Resultsmentioning

confidence: 97%

Spinning a Liquid Wheel and Driving Surface Thermomagnetic Convection with Light

Liu,

Lin,

Qin

et al. 2023

Advanced Materials

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A typical Tesla thermomagnetic engine employs a solid magnetic wheel to convert thermal energy into mechanical energy, while thermomagnetic convection in ferrofluid is still challenging to observe because it is a volume convection that occurs in an enclosed space. Using a water‐based ferrofluid, we demonstrate a liquid Tesla thermomagnetic engine and report the observation of thermomagnetic convection on a free surface. Both types of fluid motions are driven by light and observed by simply placing ferrofluid on a cylindrical magnet. The surface thermomagnetic convection on the free surface is made possible by eliminating the Marangoni effect, while the spinning of the liquid wheel is achieved through the solid‐like behavior of the ferrofluid under a strong magnetic field. Increasing the magnetic field reveals a transition from simple thermomagnetic convection to a combination of the central spin of the spiky wheel surrounded by thermomagnetic convection in the outer region of the ferrofluid. We further demonstrate the coupling between multiple ferrofluid wheels through a fluid bridge. These demonstrations not only unveil the unique properties of ferrofluid but also provide a new platform for studying complex fluid dynamics and thermomagnetic convection, opening up exciting opportunities for light‐controlled fluid actuation and soft robotics.This article is protected by copyright. All rights reserved

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Section: Resultsmentioning

confidence: 97%

Spinning a Liquid Wheel and Driving Surface Thermomagnetic Convection with Light

Liu,

Lin,

Qin

et al. 2023

Advanced Materials

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“…In order to delve into the underlying mechanism, the FEA incorporated temperature field, velocity field, concentration fields, and particle trajectories based on a real model (Figure 3a,b) and computational eqs S1−S10. 58 The visualization results of FEA and experiments clearly show the rules and trend for the crystal transformation (Figure 3c−j, Figures S11 and S12, and Videos S1−S6). Simultaneously, in situ optical observations revealed the layered particle dispersion within the droplet, confirming the distribution of particle trajectories caused by the Marangoni effect (Figure 3b,d and Figure S13).…”

mentioning

confidence: 83%

“…To investigate the mass and heat transport in the transformation process from 3D ZIF to 2D ZIF, we performed finite element analysis (FEA) and experiments under three conditions of two variables: ambient temperature ( T , 298 and 278 K) and droplet bottom diameter ( D , 10 and 20 mm). In order to delve into the underlying mechanism, the FEA incorporated temperature field, velocity field, concentration fields, and particle trajectories based on a real model (Figure a,b) and computational eqs S1–S10 . The visualization results of FEA and experiments clearly show the rules and trend for the crystal transformation (Figure c–j, Figures S11 and S12, and Videos S1–S6).…”

mentioning

confidence: 96%

Transformation of ZIF-67 Nanocubes to ZIF-L Nanoframes

Bai,

Chen,

Wang

et al. 2023

J. Am. Chem. Soc.

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Investigating the process of crystalline transformation in metal−organic frameworks (MOFs) has significant implications in advancing our understanding of the growth mechanisms and design of innovative materials. This study achieves a theoretically impossible transformation direction from three-dimensional (3D) zeolitic imidazolate nanocubes (ZIF) to twodimensional (2D) ZIF nanoframes through the Marangoni effect in droplets. This transformation challenges the established belief that only a transition from 2D ZIF-L to 3D ZIF-67 is possible, which neglects the reverse process. Finite element analysis indicates that the conversion from 3D ZIF to 2D ZIF is feasible when uniform mass distribution and heat transport are guaranteed under Marangoni flow. This research not only demonstrates an alternative pathway for MOF crystalline transformation but also provides a fresh perspective on the construction of MOF nanoframes.

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“…[9][10][11][12][13] Further, a droplet that is placed on top of the hydrophobic substrate during the evaporation process, specically one that produces Marangoni effects, has been found to shorten the response time and enhance the limit of detection. [14][15][16][17] The process of evaporation increases the sensitivity of the device to detect the presence of DNA molecules. 18,19 A recent study achieved the detection of milk adulteration by applying the evaporation process on a glass substrate.…”

Section: Introductionmentioning

confidence: 99%