Liquids

14 pages, 1519 KiB

Open AccessArticle

Polar-Twisted, Nano-Modulated Nematics: Form Chirality and Physical Properties

by Alexandros G. Vanakaras, Edward T. Samulski and Demetri J. Photinos

Liquids 2024, 4(4), 768-781; https://doi.org/10.3390/liquids4040043 - 26 Nov 2024

Viewed by 494

Recently, two new polymorphs have been added to the nematic class: the polar-twisted nematic (N_PT) in 2016 and the ferroelectric nematic (N_F) in 2020. Comprised of achiral molecules, both exhibit local polar ordering and adopt modulated structures, right- and [...] Read more.

Recently, two new polymorphs have been added to the nematic class: the polar-twisted nematic (N_PT) in 2016 and the ferroelectric nematic (N_F) in 2020. Comprised of achiral molecules, both exhibit local polar ordering and adopt modulated structures, right- and left-handed helical organizations—form chirality—albeit on vastly different dimensional scales; modulations have a ~10 nanometer pitch in the N_PT and ~500 nm in the N_F. Here, we focus on the structure and symmetries of the N_PT phase and the ensuing physical properties. Based on an array of order parameters that fully describe the molecular ordering and the nano-modulations thereof, we present a consistent formulation of the dielectric, optical, surface anchoring, and elasticity properties of the N_PT materials. We show that these properties are distinctly different from those associated with an elastically modulated, locally uniaxial, nematic. Full article

(This article belongs to the Section Molecular Liquids)

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24 pages, 12607 KiB

Open AccessReview

Overview of Typical Projects for Geological Storage of CO₂ in Offshore Saline Aquifers

by Lintao Li, Yuming Liu, Yanzun Li, Ziyi Wang, Kai Guo, Qianli Ma, Yingying Cui, Kaibang Liu and Cong Chen

Liquids 2024, 4(4), 744-767; https://doi.org/10.3390/liquids4040042 - 26 Nov 2024

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Abstract

With the continuous growth of global energy demand, greenhouse gas emissions are also rising, leading to serious challenges posed by climate change. Carbon Capture, Utilization, and Storage (CCUS) technology is considered one of the key pathways to mitigate climate change. Among the CCUS [...] Read more.

With the continuous growth of global energy demand, greenhouse gas emissions are also rising, leading to serious challenges posed by climate change. Carbon Capture, Utilization, and Storage (CCUS) technology is considered one of the key pathways to mitigate climate change. Among the CCUS technologies, CO₂ storage in offshore saline aquifers has gained significant attention in recent years. This paper conducts an in-depth analysis of the Sleipner and Snøhvit projects in Norway and the Tomakomai project in Japan, exploring key issues related to the application, geological characteristics, injection strategies, monitoring systems, and simulation methods of CO₂ storage in offshore saline aquifers. This study finds that CO₂ storage in offshore saline aquifers has high safety and storage potential but faces several challenges in practical applications, such as geological reservoir characteristics, technological innovation, operational costs, and social acceptance. Therefore, it is necessary to further strengthen technological innovation and policy support to promote the development and application of CO₂ storage in offshore saline aquifers. This study provides valuable experiences and insights for similar projects worldwide, contributing to the sustainable development of CO₂ storage in offshore saline aquifers and making a greater contribution to achieving global net-zero emission targets. Full article

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12 pages, 1349 KiB

Open AccessArticle

Interactions of Laser-Induced Thermal Plume with Liquid–Air Interfaces in Straight-Chain Alcohols

by Reese W. Anderson, Allison I. Anderson, Mark W. Gealy and Darin J. Ulness

Liquids 2024, 4(4), 732-743; https://doi.org/10.3390/liquids4040041 - 22 Nov 2024

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Abstract

This study investigates the dynamics of thermal plumes interacting with the liquid–air interface in straight-chain alcohols and their mixtures using a photothermal imaging technique based on thermal lensing. This method enables the indirect measurement of temperature gradients via changes in refractive index caused [...] Read more.

This study investigates the dynamics of thermal plumes interacting with the liquid–air interface in straight-chain alcohols and their mixtures using a photothermal imaging technique based on thermal lensing. This method enables the indirect measurement of temperature gradients via changes in refractive index caused by localized laser heating. Employing a collimated laser beam, the results show the formation and evolution of cylindrical heated zones and their interactions with the liquid–air interface. The study reveals that, while some alcohols exhibit stable surface behaviors, others demonstrate complex dynamical behaviors, including strong stable steady-state oscillations. The findings contribute to understanding fluid dynamics in molecular liquids near their liquid–air interfaces. Full article

(This article belongs to the Special Issue Energy Transfer in Liquids)

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22 pages, 2987 KiB

Open AccessArticle

A Machine Learning Free Energy Functional for the 1D Reference Interaction Site Model: Towards Prediction of Solvation Free Energy for All Solvent Systems

by Jonathan G. M. Conn, Abdullah Ahmad and David S. Palmer

Liquids 2024, 4(4), 710-731; https://doi.org/10.3390/liquids4040040 - 8 Nov 2024

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Abstract

Understanding the interactions between solutes and solvents is vital in many areas of the chemical sciences. Solvation free energy (SFE) is an important thermodynamic property in characterising molecular solvation and so accurate prediction of this property is sought after. The One-Dimensional Reference Interaction [...] Read more.

Understanding the interactions between solutes and solvents is vital in many areas of the chemical sciences. Solvation free energy (SFE) is an important thermodynamic property in characterising molecular solvation and so accurate prediction of this property is sought after. The One-Dimensional Reference Interaction Site Model (RISM) is a well-established method for modelling solvation, but it is known to yield large errors in the calculation of SFE. In this work, we show that a single machine learning free energy functional for RISM can accurately model solvation thermodynamics in multiple solvents. A convolutional neural network is trained on solvation free energy density functions calculated by RISM for small organic molecules in approximately 100 different solvent systems. We achieve an average RMSE of 1.41 kcal/mol and an

R^{2}

of 0.89 across all solvent systems. We also compare the performance for the most and least commonly represented solvents and show that higher accuracy is generally seen with higher volumes of data, with RMSE values of 0.69–1.29 kcal/mol and

R^{2}

values of 0.78–0.97 for solvents with more than 50 data points. We have shown that machine learning can greatly improve solvation free energy predictions in RISM, while demonstrating that the methodology is generalisable across solvent systems. This represents a significant step towards a universal machine learning SFE functional for RISM. Full article

(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)

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8 pages, 484 KiB

Open AccessArticle

On the Diffusion of Anti-Tuberculosis Drugs in Cyclodextrin-Containing Aqueous Solutions

by M. Melia Rodrigo, Ana M. T. D. P. V. Cabral, Sónia I. G. Fangaia, Afonso C. Nogueira, Artur J. M. Valente, Ana C. F. Ribeiro and Miguel A. Esteso

Liquids 2024, 4(4), 702-709; https://doi.org/10.3390/liquids4040039 - 12 Oct 2024

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Abstract

In this work, we propose a comprehensive experimental study of the diffusion of isoniazid, one of the first-line anti-tuberculosis drugs, in combination with another drug (ethambutol dihydrochloride) and with different cyclodextrins as carrier molecules, for facilitated transport and enhanced solubility. For that, ternary [...] Read more.

In this work, we propose a comprehensive experimental study of the diffusion of isoniazid, one of the first-line anti-tuberculosis drugs, in combination with another drug (ethambutol dihydrochloride) and with different cyclodextrins as carrier molecules, for facilitated transport and enhanced solubility. For that, ternary mutual diffusion coefficients measured by the Taylor dispersion method (D₁₁, D₂₂, D₁₂, and D₂₁) are determined for aqueous solutions containing isoniazid and different cyclodextrins (that is, α–CD, β–CD, and γ–CD) at 298.15 K. From the significant effect of the presence of these carbohydrates on the diffusion of this drug, interactions between these components are suggested. Support for this arose from models, which shows that these effects may be due to the formation of 1:1 (CDs:isoniazid) complexes. Full article

(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)

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13 pages, 2850 KiB

Open AccessArticle

Thermodynamic Properties of Two Cinnamate Derivatives with Flavor and Fragrance Features

by Vera L. S. Freitas, Carlos A. O. Silva and Maria D. M. C. Ribeiro da Silva

Liquids 2024, 4(4), 689-701; https://doi.org/10.3390/liquids4040038 - 11 Oct 2024

Viewed by 762

Abstract

The standard molar enthalpies of formation in the liquid phase for ethyl (E)-cinnamate and ethyl hydrocinnamate, two cinnamate derivatives with notable flavor and fragrance characteristics, were determined experimentally using combustion calorimetry in an oxygen atmosphere. To derive the gas-phase enthalpies of [...] Read more.

The standard molar enthalpies of formation in the liquid phase for ethyl (E)-cinnamate and ethyl hydrocinnamate, two cinnamate derivatives with notable flavor and fragrance characteristics, were determined experimentally using combustion calorimetry in an oxygen atmosphere. To derive the gas-phase enthalpies of formation for these derivatives, their enthalpies of vaporization were measured using a high-temperature Calvet microcalorimeter and the vacuum drop microcalorimetric technique. Additionally, a computational analysis employing the G3(MP2)//B3LYP composite method was conducted to calculate the gas-phase standard enthalpies of formation at T = 298.15 K for both compounds. These findings enabled a detailed assessment and analysis of the structural and energetic effects of the vinyl and ethane moieties between the phenyl and carboxylic groups in the studied compounds. Considering the structural features of ethyl (E)-cinnamate and ethyl hydrocinnamate, a gas-phase enthalpy of hydrogenation analysis was conducted to explore their energetic profiles more thoroughly. Full article

(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)

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26 pages, 1298 KiB

Open AccessArticle

Quantum Chemical (QC) Calculations and Linear Solvation Energy Relationships (LSER): Hydrogen-Bonding Calculations with New QC-LSER Molecular Descriptors

by Costas Panayiotou

Liquids 2024, 4(4), 663-688; https://doi.org/10.3390/liquids4040037 - 4 Oct 2024

Viewed by 628

Abstract

A new method, based on quantum chemical calculations, is proposed for the thermodynamically consistent reformulation of QSPR-type Linear Free-Energy Relationship (LFER) models. This reformulation permits the extraction of valuable information on intermolecular interactions and its transfer in other LFER-type models, in acidity/basicity scales, [...] Read more.

A new method, based on quantum chemical calculations, is proposed for the thermodynamically consistent reformulation of QSPR-type Linear Free-Energy Relationship (LFER) models. This reformulation permits the extraction of valuable information on intermolecular interactions and its transfer in other LFER-type models, in acidity/basicity scales, or even in equation-of-state models. New molecular descriptors of electrostatic interactions are derived from the distribution of molecular surface charges obtained from COSMO-type quantum chemical calculations. The widely used and very successful Abraham’s Linear Solvation Energy Relationship (LSER) model is selected as the reference LSER model for the calculations in solute–solvent systems as well as in solute self-solvation. Hydrogen-bonding free energies, enthalpies, and entropies are now derived for a variety of common solutes. The capacity of the method to address the role of conformational changes in solvation quantities is discussed. The perspectives of the LSER model with the implementation of the new descriptors are also discussed. Full article

(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)

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Liquids, Volume 4, Issue 4 (December 2024) – 7 articles

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