Anomalous thermal conductivity near the upper critical solution temperature of a binary liquid mixture

The coexistence curve and critical opalescence of a binary liquid mixture, triethylamine–water, have been reinvestigated. The measurements showed that the coexistence curve appears to follow a cubic relation to within about 0.003° of the critical solution temperature, and in this range, there is no evidence of a flat region. Furthermore, within the range of the values of s/λ(where s = 2 sin (θ/2), λ = wavelength in the medium, and s/λ varied from 1.2 × 10−4 to 7.0 × 10−4 Å−1) and temperatures studied, the light scattering data are in good agreement with the Debye theory (J. Chem. Phys. 31, 680 (1959)). The molecular interaction range of Debye was found to be 5.1 ± 0.3 Å.

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Temperature-Induced Liquid Crystal Microdroplet Formation in a Partially Miscible Liquid Mixture

10.26434/chemrxiv.9731030 ◽

2019 ◽

Author(s):

Mehzabin Patel ◽

Anand N. Pallipurath Radhakrishnan ◽

Ludovic Bescher ◽

Elwin Hunter-Sellars ◽

Benjamin Schmidt-Hansberg ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Mixture ◽

Liquid Mixtures ◽

Solution Temperature ◽

Material System ◽

Reversible Process ◽

Critical Solution Temperature ◽

Binary Liquid ◽

Partially Miscible ◽

Extraction Processes

The controlled formation of microdroplets through temperature variation is an intriguing concept for binary liquid mixtures with a critical solution temperature. Here, we investigate this phenomenon for a blend of methanol (MeOH) and a thermotropic liquid crystal (LC) 4-Cyano-4’-pentylbiphenyl (5CB). A near-room-temperatureinduced phase separation leads to nucleation, growth and coalescence of mesogen-rich droplets. The size and number of the droplets is tunable on the microscopic scale by variation of temperature quench depth and cooling rate. Further cooling induces a phase transition to nematic droplets with radial configuration, well-defined sizes and stability over the course of an hour. This fully reversible process is an interesting material system with relevance in diagnostics, optoelectronics, materials templating and extraction processes.<br>

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Temperature-Induced Liquid Crystal Microdroplet Formation in a Partially Miscible Liquid Mixture

10.26434/chemrxiv.9731030.v1 ◽

2019 ◽

Author(s):

Mehzabin Patel ◽

Anand N. Pallipurath Radhakrishnan ◽

Ludovic Bescher ◽

Elwin Hunter-Sellars ◽

Benjamin Schmidt-Hansberg ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Mixture ◽

Liquid Mixtures ◽

Solution Temperature ◽

Material System ◽

Reversible Process ◽

Critical Solution Temperature ◽

Binary Liquid ◽

Partially Miscible ◽

Extraction Processes

The controlled formation of microdroplets through temperature variation is an intriguing concept for binary liquid mixtures with a critical solution temperature. Here, we investigate this phenomenon for a blend of methanol (MeOH) and a thermotropic liquid crystal (LC) 4-Cyano-4’-pentylbiphenyl (5CB). A near-room-temperatureinduced phase separation leads to nucleation, growth and coalescence of mesogen-rich droplets. The size and number of the droplets is tunable on the microscopic scale by variation of temperature quench depth and cooling rate. Further cooling induces a phase transition to nematic droplets with radial configuration, well-defined sizes and stability over the course of an hour. This fully reversible process is an interesting material system with relevance in diagnostics, optoelectronics, materials templating and extraction processes.<br>

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Phase behaviour and applications of a binary liquid-liquid mixture of methanol and a thermotropic liquid crystal

10.26434/chemrxiv.5662474 ◽

2017 ◽

Author(s):

Luis A Serrano ◽

Maximiliano J Fornerod ◽

Ye Yang ◽

Simon Gaisford ◽

Francesco Stellacci ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Mixture ◽

Phase Behaviour ◽

Solution Temperature ◽

Eosin Y ◽

Phase Mixing ◽

Binary Liquid ◽

Thermotropic Liquid Crystal ◽

Upper Critical Solution Temperature ◽

Sudan Iv

Herein, we report on the phase behaviour of a binary liquid-liquid mixture composed of methanol (MeOH) and the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB). The corresponding phase diagram combines features of a conventional liquid-liquid mixture with characteristics that are particular to the nematic liquid crystal. We observe four arrangements as a function of composition and temperature, namely monophasic isotropic, monophasic nematic, biphasic isotropic-isotropic and biphasic isotropic-nematic, with an upper critical solution temperature of 298 K. The interplay of nematogenic and non-nematogenic species offers a number of applications. Dilution of mesogens with MeOH allows to control the isotropic-to-nematic phase transition of 5CB over a range of 35 K. The tunability of phase mixing and phase composition in an accessible temperature window provides novel routes for the extraction of target compounds, here shown for Eosin Y, Doxorubicin, Crystal Violet and Sudan IV.

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Phase behaviour and applications of a binary liquid-liquid mixture of methanol and a thermotropic liquid crystal

10.26434/chemrxiv.5662474.v1 ◽

2017 ◽

Author(s):

Luis A Serrano ◽

Maximiliano J Fornerod ◽

Ye Yang ◽

Simon Gaisford ◽

Francesco Stellacci ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Mixture ◽

Phase Behaviour ◽

Solution Temperature ◽

Eosin Y ◽

Phase Mixing ◽

Binary Liquid ◽

Thermotropic Liquid Crystal ◽

Upper Critical Solution Temperature ◽

Sudan Iv

Herein, we report on the phase behaviour of a binary liquid-liquid mixture composed of methanol (MeOH) and the thermotropic liquid crystal 4-Cyano-4'-pentylbiphenyl (5CB). The corresponding phase diagram combines features of a conventional liquid-liquid mixture with characteristics that are particular to the nematic liquid crystal. We observe four arrangements as a function of composition and temperature, namely monophasic isotropic, monophasic nematic, biphasic isotropic-isotropic and biphasic isotropic-nematic, with an upper critical solution temperature of 298 K. The interplay of nematogenic and non-nematogenic species offers a number of applications. Dilution of mesogens with MeOH allows to control the isotropic-to-nematic phase transition of 5CB over a range of 35 K. The tunability of phase mixing and phase composition in an accessible temperature window provides novel routes for the extraction of target compounds, here shown for Eosin Y, Doxorubicin, Crystal Violet and Sudan IV.

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Selective Hydrogen Bonding Controls Temperature Response of Layer-by-Layer Upper Critical Solution Temperature Micellar Assemblies

Soft Matter ◽

10.1039/d0sm01997f ◽

2021 ◽

Author(s):

Aliaksei Aliakseyeu ◽

Victoria Albright ◽

Danielle Yarbrough ◽

Samantha Hernandez ◽

Qing Zhou ◽

...

Keyword(s):

Hydrogen Bonding ◽

Methacrylic Acid ◽

Temperature Response ◽

Solution Temperature ◽

Layer By Layer ◽

Critical Solution Temperature ◽

Hydrogen Bonding Interactions ◽

Upper Critical Solution Temperature ◽

Lbl Films

This work establishes a correlation between the selectivity of hydrogen-bonding interactions and the functionality of micelle-containing layer-by-layer (LbL) assemblies. Specifically, we explore LbL films formed by assembly of poly(methacrylic acid)...

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Phase separation of binary mixtures induced by soft centrifugal fields

Physical Chemistry Chemical Physics ◽

10.1039/d0cp01527j ◽

2021 ◽

Author(s):

Thomas Zemb ◽

Rose Rosenberg ◽

Stjepan Marčelja ◽

Dirk Haffke ◽

Jean-François Dufrêche ◽

...

Keyword(s):

Phase Separation ◽

Critical Point ◽

Binary Mixtures ◽

Liquid Mixture ◽

Model System ◽

Binary Liquid Mixture ◽

Miscibility Gap ◽

Critical Fluctuations ◽

Binary Liquid

We use the model system ethanol–dodecane to demonstrate that giant critical fluctuations induced by easily accessible weak centrifugal fields as low as 2000g can be observed above the miscibility gap even far from the critical point of a binary liquid mixture.

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