Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

Gugliotti, Marcos; Baptista, Maurı́cio S.; Politi, Mário José; Silverstein, Todd P.; Slater, Carl

doi:10.1021/ed081p824

Cited by 37 publications

(20 citation statements)

References 12 publications

(14 reference statements)

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“…We also observed that at higher temperatures ( T > T co + 25 °C) convective flows within the fluid are induced. This results from the creation of a gradient of surface tensions along the liquid surface due to uneven temperature distribution – a thermocapillary phenomenon known as the Marangoni effect 45 – 47 . Therefore, we found that the ideal temperature range for printing is between T co + 15 °C and T co + 25 °C.…”

Section: Resultsmentioning

confidence: 99%

Encapsulating Networks of Droplet Interface Bilayers in a Thermoreversible Organogel

Challita

Najem

Monroe

et al. 2018

Sci Rep

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The development of membrane-based materials that exhibit the range and robustness of autonomic functions found in biological systems remains elusive. Droplet interface bilayers (DIBs) have been proposed as building blocks for such materials, owing to their simplicity, geometry, and capability for replicating cellular phenomena. Similar to how individual cells operate together to perform complex tasks and functions in tissues, networks of functionalized DIBs have been assembled in modular/scalable networks. Here we present the printing of different configurations of picoliter aqueous droplets in a bath of thermoreversible organogel consisting of hexadecane and SEBS triblock copolymers. The droplets are connected by means of lipid bilayers, creating a network of aqueous subcompartments capable of communicating and hosting various types of chemicals and biomolecules. Upon cooling, the encapsulating organogel solidifies to form self-supported liquid-in-gel, tissue-like materials that are robust and durable. To test the biomolecular networks, we functionalized the network with alamethicin peptides and alpha-hemolysin (αHL) channels. Both channels responded to external voltage inputs, indicating the assembly process does not damage the biomolecules. Moreover, we show that the membrane properties may be regulated through the deformation of the surrounding gel.

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Section: Resultsmentioning

confidence: 99%

Encapsulating Networks of Droplet Interface Bilayers in a Thermoreversible Organogel

Challita

Najem

Monroe

et al. 2018

Sci Rep

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show abstract

“…But flow can also result from gradients in surface tension through a phenomenon known as the Marangoni effect. Gradients of surface tension at the interface of fluids result from curvature [7,8] or temperature [9,10] gradients, or from gradients in the concentration [11,12,13,14] of surfactants, i.e. molecules which attach to fluid interfaces and reduce surface tension.…”

Section: Introductionmentioning

confidence: 99%

Feedback control of photoresponsive fluid interfaces

Grawitter

Stark

2018

Soft Matter

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Photoresponsive surfactants provide a unique microfluidic driving mechanism. Since they switch between two molecular shapes under illumination and thereby affect surface tension of fluid interfaces, Marangoni flow along the interface occurs. To describe the dynamics of the surfactant mixture at a planar interface, we formulate diffusion-advection-reaction equations for both surfactant densities. They also include adsorption from and desorption into the neighboring fluids and photoisomerization by light. We then study how the interface responds when illuminated by spots of light. Switching on a single light spot, the density of the switched surfactant spreads in time and assumes an exponentially decaying profile in steady state. Simultaneously, the induced radial Marangoni flow reverses its flow direction from inward to outward. We use this feature to set up specific feedback rules, which couple the advection velocities sensed at the light spots to their intensities. As a result two neighboring spots switch on and off alternately. Extending the feedback rule to light spots arranged on the vertices of regular polygons, we observe periodic switching patterns for even-sided polygons, where two sets of next-nearest neighbors alternate with each other. A triangle and pentagon also show regular oscillations, while heptagon and nonagon exhibit irregular oscillations due to frustration. While our findings are specific to the chosen set of parameters, they show how complex patterns at photoresponsive fluid interfaces emerge from simple feedback coupling.

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“…Marangoni flows occur when a gradient in interfacial tension results in a net stress on the interface, inducing a flow along the interface towards the direction of higher interfacial tension. These gradients can be caused by chemical gradients (such as in the famous example, tears of wine [85]) or by thermal gradients [86]. Chemical gradients have been shown to cause double emulsions to act as self propelling micro-swimmers [87].…”

Section: Code Availabilitymentioning

confidence: 99%

Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components

Nagelberg¹

2020

Springer Theses

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Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

Cited by 37 publications

References 12 publications

Encapsulating Networks of Droplet Interface Bilayers in a Thermoreversible Organogel

Encapsulating Networks of Droplet Interface Bilayers in a Thermoreversible Organogel

Feedback control of photoresponsive fluid interfaces

Dynamic and Stimuli-Responsive Multi-Phase Emulsion Droplets for Optical Components

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