Relaxation oscillations of solutal Marangoni convection at curved interfaces

Schwarzenberger, Karin; Aland, Sebastian; Domnick, H.; Odenbach, Stefan; Eckert, Kerstin

doi:10.1016/j.colsurfa.2015.06.031

Cited by 30 publications

(27 citation statements)

References 52 publications

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“…For example, this phenomenon can be observed in the vicinity of an air–liquid interface with inhomogeneous concentration of the soluble surfactant (aqueous solution of acetic acid) along the surface [ 33 , 35 ]. Similar oscillations were obtained in an immiscible liquid–liquid system, consisting of paraffin oil and water, with isopropyl alcohol as surface-active solute [ 36 ]. The mechanism of these oscillations was found to be a periodic coupling of the Marangoni effect, buoyancy convection acting in the presence of gravity and the restoring effect of diffusion.…”

Section: Introductionsupporting

confidence: 64%

“…The experimental system consists of two immiscible liquids placed in a Hele–Shaw cell as described below. The oscillations can be excited either near drops which formed during the filling procedure or near air bubbles produced via a capillary [ 36 ]. Here, we focus on the former case, while a second system with air bubbles is analyzed in Section 2.2 .…”

Section: Experimental Observations Of Relaxation Oscillationsmentioning

confidence: 99%

“…The liquid–liquid system consists of paraffin oil and water with 4.6 wt.% isopropyl alcohol being dissolved in the organic phase. The material parameters of this system are listed in [ 36 ]. All chemical substances are used as purchased.…”

Section: Experimental Observations Of Relaxation Oscillationsmentioning

confidence: 99%

“…In this work, a recently discovered hydrodynamic effect is employed to create a novel, adaptive micromixer. For many years, the authors have been involved in the experimental and theoretical studies of the fundamental properties of soluto-capillary phenomena in different immiscible systems with [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] and without chemical reactions [ 32 , 33 , 34 , 35 , 36 ]. Among the various effects studied by the authors, a prominent finding was that solutal Marangoni convection frequently is accompanied by intensive relaxation oscillations.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Micromixer Based on the Solutocapillary Marangoni Effect in a Continuous-Flow Microreactor

et al. 2018

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Continuous-flow microreactors are an important development in chemical engineering technology, since pharmaceutical production needs flexibility in reconfiguring the synthesis system rather than large volumes of product yield. Microreactors of this type have a special vessel, in which the convective vortices are organized to mix the reagents to increase the product output. We propose a new type of micromixer based on the intensive relaxation oscillations induced by a fundamental effect discovered recently. The mechanism of these oscillations was found to be a coupling of the solutal Marangoni effect, buoyancy and diffusion. The phenomenon can be observed in the vicinity of an air–liquid (or liquid–liquid) interface with inhomogeneous concentration of a surface-active solute. Important features of the oscillations are demonstrated experimentally and numerically. The periodicity of the oscillations is a result of the repeated regeneration of the Marangoni driving force. This feature is used in our design of a micromixer with a single air bubble inside the reaction zone. We show that the micromixer does not consume external energy and adapts to the medium state due to feedback. It switches on automatically each time when a concentration inhomogeneity in the reaction zone occurs, and stops mixing when the solution becomes sufficiently uniform.

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Section: Introductionsupporting

confidence: 64%

Section: Experimental Observations Of Relaxation Oscillationsmentioning

confidence: 99%

Section: Experimental Observations Of Relaxation Oscillationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adaptive Micromixer Based on the Solutocapillary Marangoni Effect in a Continuous-Flow Microreactor

et al. 2018

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“…Solutal Marangoni convection at curved menisci was studied in a nonreactive fluid‐fluid system , . Here, a self‐oscillatory Marangoni convection was observed, caused by the interaction with buoyancy‐driven convection in a stable vertical stratification of the surfactant concentration.…”

Section: Introductionmentioning

confidence: 99%

Meniscus Asymmetry and Chemo‐Marangoni Convection in Capillaries

et al. 2017

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Dedicated to Professor Rüdiger Lange on the occasion of his 65th birthdayA liquid-liquid system inside a capillary in which an interfacial reaction leads to in situ production of a surfactant was studied experimentally. The resulting chemo-Marangoni convection induces periodic spreading-dewetting cycles in laboratory experiments. By selected experiments in microgravity, the individual phenomena of the system dynamics could be isolated. The spreading-dewetting cycles result from a complex interplay between the decrease in interfacial tension due to the production of surfactant, the chemo-Marangoni convection, and the gravity-driven deformation of the meniscus shape.

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Phase Field Models for Two-Phase Flow with Surfactants and Biomembranes

Aland

2017

Transport Processes at Fluidic Interfaces

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Relaxation oscillations of solutal Marangoni convection at curved interfaces

Cited by 30 publications

References 52 publications

Adaptive Micromixer Based on the Solutocapillary Marangoni Effect in a Continuous-Flow Microreactor

Adaptive Micromixer Based on the Solutocapillary Marangoni Effect in a Continuous-Flow Microreactor

Meniscus Asymmetry and Chemo‐Marangoni Convection in Capillaries

Phase Field Models for Two-Phase Flow with Surfactants and Biomembranes

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