Kinetics of phase separation in binary liquid mixtures

Liquid-liquid microfluidic systems rely on the intricate control over the fluid properties of either miscible or immiscible mixtures. Herein, we report on the use of partially miscible binary liquid mixtures that lend their microfluidic properties from a highly temperature-sensitive mixing and phase separation behaviour. For a blend composed of the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB) and methanol, mixing at temperatures above the upper critical solution temperature (UCST; 24.4°C) leads to a uniform single phase while partial mixing can be achieved at temperatures below the UCST. Thermally-driven phase separation inside the microfluidic channels results in the spontaneous formation of very regular phase arrangements, namely in droplets, plug, slug and annular flow. We map different flow regimes and relate findings to the role of interfacial tension and viscosity and their temperature dependence. Importantly, different flow regimes can be achieved at constant channel architecture and flow rate by varying the temperature of the blend. A consistent behaviour is observed for a binary liquid mixture with lower critical solution temperature, namely 2,6-lutidine and water. This temperature-responsive approach to microfluidics is an interesting candidate for multi-stage processes, selective extraction and sensing applications.

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Microfluidics of Binary Liquid Mixtures with Temperature-Dependent Miscibility

10.26434/chemrxiv.6970301.v2 ◽

2019 ◽

Author(s):

Maximiliano J. Fornerod ◽

Esther Amstad ◽

Stefan Guldin

Keyword(s):

Phase Separation ◽

Flow Regimes ◽

Liquid Mixtures ◽

Binary Liquid Mixtures ◽

Solution Temperature ◽

Microfluidic Channels ◽

Temperature Sensitive ◽

Critical Solution Temperature ◽

Binary Liquid ◽

Sensing Applications

Liquid-liquid microfluidic systems rely on the intricate control over the fluid properties of either miscible or immiscible mixtures. Herein, we report on the use of partially miscible binary liquid mixtures that lend their microfluidic properties from a highly temperature-sensitive mixing and phase separation behaviour. For a blend composed of the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB) and methanol, mixing at temperatures above the upper critical solution temperature (UCST; 24.4°C) leads to a uniform single phase while partial mixing can be achieved at temperatures below the UCST. Thermally-driven phase separation inside the microfluidic channels results in the spontaneous formation of very regular phase arrangements, namely in droplets, plug, slug and annular flow. We map different flow regimes and relate findings to the role of interfacial tension and viscosity and their temperature dependence. Importantly, different flow regimes can be achieved at constant channel architecture and flow rate by varying the temperature of the blend. A consistent behaviour is observed for a binary liquid mixture with lower critical solution temperature, namely 2,6-lutidine and water. This temperature-responsive approach to microfluidics is an interesting candidate for multi-stage processes, selective extraction and sensing applications.

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Microfluidics of binary liquid mixtures with temperature-dependent miscibility

Molecular Systems Design & Engineering ◽

10.1039/c9me00127a ◽

2020 ◽

Vol 5 (1) ◽

pp. 358-365 ◽

Cited By ~ 2

Author(s):

Maximiliano J. Fornerod ◽

Esther Amstad ◽

Stefan Guldin

Keyword(s):

Phase Separation ◽

Liquid Mixtures ◽

Flow Patterns ◽

Binary Liquid Mixtures ◽

Temperature Dependent ◽

Microfluidic Mixing ◽

Binary Liquid ◽

Partially Miscible

We report on the use of temperature to actively control the microfluidic mixing, phase separation and flow patterns of partially miscible binary liquid mixtures.

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Critical point phase separation in binary liquid mixtures

Journal of Chemical Education ◽

10.1021/ed070p775 ◽

1993 ◽

Vol 70 (9) ◽

pp. 775

Author(s):

L. H. Bowen ◽

M. L. Benevides

Keyword(s):

Phase Separation ◽

Critical Point ◽

Liquid Mixtures ◽

Binary Liquid Mixtures ◽

Binary Liquid

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Convective Instabilities and Dynamic Structures in Phase-Separation Processes of Binary Liquid Mixtures

Zeitschrift für Naturforschung A ◽

10.1515/zna-1986-0414 ◽

1986 ◽

Vol 41 (4) ◽

pp. 678-680

Author(s):

Michael Dittmann ◽

Gerhard M. Schneider

Keyword(s):

Phase Separation ◽

Dissipative Structure ◽

Liquid Mixtures ◽

Binary Liquid Mixtures ◽

Pressure Jump ◽

Separation Processes ◽

Binary Liquid ◽

Convective Instabilities ◽

Dynamic Structures ◽

Rayleigh Benard

In pressure jump experiments on the phase separation of binary liquid mixtures of cyclohexane + methanol, an organisation of the finely dispersed precipitate could be observed to give a macroscopic dissipative structure during the early stages of the ageing process of the newly formed phase. Preliminary phenomenological investigations suggest a mechanism similar to the Rayleigh-Benard instability (RBI) and the Soret-driven instability (SDI).

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