Molecular Liquids Research Articles

Evolving molecular classification of aggressive B-cell lymphoma.

This review aims to provide an overview of the latest developments in the classification and molecular understanding of aggressive B-cell lymphomas, specifically focusing on diffuse large B-cell lymphoma (DLBCL) and high-grade B-cell lymphoma (HGBL). Advances in molecular techniques have led to novel ways to classify these lymphomas based on clinical, histological, transcriptional, and genetic properties. While these methods have predominantly focused on the malignant compartment, recent studies emphasize the value of profiling the tumour microenvironment for a more comprehensive disease classification. Additionally, the integration of liquid biopsies represents a promising advancement, offering less invasive and dynamic insights into tumour characteristics and treatment response. Although molecular profiles are not yet routinely used to guide therapy, emerging data highlight their potential to predict responses to novel treatments. It is our belief that integrating molecular profiling and liquid biopsies into clinical practice and research now will pave the way for more personalized and effective therapies in the future.

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering and Manufacturing — Part 4

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering and Manufacturing — Part 4

Chemical bond based machine learning model for dipole moment: Application to dielectric properties of liquid methanol and ethanol

We introduce a versatile machine-learning scheme for predicting dipole moments of molecular liquids to study dielectric properties, implemented in . We attribute the center of mass of Wannier functions, called Wannier centers, to each chemical bond and create neural network models that predict the Wannier centers for each chemical bond. Application to liquid methanol and ethanol shows that our neural network models successfully predict the dipole moment of various liquid configurations in close agreement with DFT calculations. We show that the dipole moment and dielectric constant in the liquids are greatly enhanced by the polarization of Wannier centers due to local intermolecular interactions. The calculated dielectric spectra quantitatively agree with experiments over terahertz (THz) to infrared regions. Furthermore, we investigate the physical origin of THz absorption spectra of methanol, confirming the importance of translational and librational motions. Our method is applicable to other molecular liquids and can be widely used to study their dielectric properties. Published by the American Physical Society 2024

Relaxation dynamics of a liquid in the vicinity of an attractive surface: The process of escaping from the surface.

We analyze the displacements of the particles of a glass-forming molecular liquid perpendicular to a confining solid surface using extensive molecular dynamics simulations with atomistic models. In the vicinity of an attractive surface, the liquid molecules are trapped. Transient localization of liquid molecules near the surface introduces a relaxation process related to the escape of molecules from the surface into the dynamics of the interfacial liquid layer. To describe this process, we analyze several dynamical observables of the confined liquid. The self-intermediate scattering function and the mean-squared displacement of the particles located in the interfacial layer are dominated by the process of escaping from the surface. This relaxation process is also associated with a strong heterogeneity in the mobility of the interfacial particles. The studied model liquid is hydrogenated methyl methacrylate. For the confining wall, we consider different models, namely a periodic single layer of graphene and a frozen amorphous configuration of the bulk liquid (frozen wall). Near graphene, where the liquid molecules form a layered structure and adopt parallel-to-surface orientation, a clear separation between small-scale movements of the molecules near the surface and the process of escaping from the surface is observed. This is reflected in the three-step relaxation of the interfacial layer. However, near the frozen wall, where the liquid molecules do not have a preferential alignment, a clear three-step relaxation is not seen, even though the dynamical quantities are controlled by the process of escaping from the surface.

Density isobar of water and melting temperature of ice: Assessing common density functionals.

We investigate the density isobar of water and the melting temperature of ice using six different density functionals. Machine-learning potentials are employed to ensure computational affordability. Our findings reveal significant discrepancies between various base functionals. Notably, even the choice of damping can result in substantial differences. Overall, the outcomes obtained through density functional theory are not entirely satisfactory across most utilized functionals. All functionals exhibit significant deviations either in the melting temperature or equilibrium volume, with most of them even predicting an incorrect volume difference between ice and water. Our heuristic analysis indicates that a hybrid functional with 25% exact exchange and van der Waals damping averaged between zero and Becke-Johnson dampings yields the closest agreement with experimental data. This study underscores the necessity for further enhancements in the treatment of van der Waals interactions and, more broadly, density functional theory to enable accurate quantitative predictions for molecular liquids.

Numerical modeling of partially coherent anti-Stokes Raman scattering (pCARS) in transparent molecular liquids

In this study, the key characteristics of the so called partially coherent anti-Stokes Raman scattering (pCARS) are numerically modeled in order to explain the physical nature of this nonlinear Raman effect. The experimental data obtained by Ishibashi and Hamaguchi, the pioneer researchers of pCARS, are simulated by use of analytical description different from their original physical interpretation. The numerical results for the spatial distribution of the anti-Stokes Raman signal in pCARS, the shape of the pCARS spectral line, and the dependence of the pCARS signal intensity on the laser pulse intensity, as well as on the concentration and temperature of the Raman medium, all matching the pCARS experimental data, indicate a complex parametric-stimulated mechanism of generation/amplification of pCARS. The differences of pCARS from ordinary CARS (fully coherent process of Raman scattering) are highlighted.

On the Physical Consistency of an Open Quantum Region with a Classical Reservoir in Molecular Simulation

AbstractThe possibility of treating a molecular liquid in an open region at ab initio electronic resolution embedded in a classical reservoir of energy and particles, is investigated. Because of its challenging properties and its relevance in many field of current research, the system chosen as prototype of molecular liquid is water at room conditions. A numerical protocol based on the mathematical model of open particle system is applied and the results are compared with results of a full ab initio simulation of reference. The key conclusion is that one can claim the existence of a mandatory minimal size of the quantum region in which structural and electronic properties reproduce those of reference and, at the same time, the exchange of molecules with the environment takes place as expected. This work provides a proof of concept about the possibility to systematically define a physically well founded open quantum system embedded in a classical environment. In turn, the proof of concept is a key information for the design of numerically efficient algorithms for ab initio molecular dynamics simulations of open systems.

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering & Manufacturing — Part 3

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering & Manufacturing — Part 3

Vaporisation Thermodynamics: Are Triazolium Ionic Liquids a Real Alternative to Popular Imidazolium-Based Ionic Liquids?

New experimental vapour pressures and vaporisation enthalpies of the ionic liquids [2,4-dimethyl-1,2,4-triazolium][NTf2], [2-methyl-4-ethyl-1,2,4-triazolium][NTf2], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf2] were measured using the Langmuir method in combination with the quartz crystal microbalance. New experimental vapour pressures and vaporisation enthalpies of the molecular liquids 1H-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, and 1H-1,2,3-triazole were measured using the transpiration method. Structure–property relationships between molecular and ionic liquids were studied. These results will facilitate chemical engineering calculations of processes involving ILs.

Multifaceted regulation of chiroptical properties and self‐assembly behaviors of chiral fluorescent polymers

AbstractThe multifaceted regulation of the chiroptical properties and self‐assembly behaviors of chiral fluorescent polymers is of great significance yet remains challenging to achieve. Herein, a series of novel salen‐based chiral fluorescent polymers with aggregation‐induced emission and varied substitution manners were facilely and efficiently synthesized. Multiple factors were systematically investigated on the chiroptical properties and self‐assembly performance of these polymers, which include molecular structures, solvent environments, metal coordination, and liquid crystal (LC) assemblies. Sutle change in the solvent composition can lead to diverse assembly morphologies of all these chiral polymers, from single‐handed helical fibers, helical toroids or loops, to spherical structures, consequently leading to an aggregation‐reduced circular dichroism (CD) phenomenon. The polymers bearing salen units show highly selective and reversible coordination with Zn2+ and can also induce multiple responses in the absorption, luminescence, CD, and circularly polarized luminescence (CPL) of these chiral fluorescent polymers via a coordination‐ and dissociation‐initiated self‐assembly tuning. Furthermore, a small amount of the chiral fluorescent polymer in can induce achiral nematic 4‐cyano‐4′‐n‐pentylbiphenyl (5CB) to form ordered chiral nematic LC phase with significant improvement in their CD and CPL signal. The absolute absorption and luminescent dissymmetry factors of the resulting supramolecular assemblies can reach the order of 10−1.

Preparation and properties of phosphorus-containing thermotropic liquid crystal copolyester fibers with excellent flame retardance and mechanical property

In order to acquire polymeric fibers have both excellent flame retardance and mechanical properties, high molecular weight phosphorus-containing liquid crystal copolyesters derived from 6-hydroxy-2-naphthenic acid (HNA), terephthalic acid (TA) and 10-(2,5-dihydroxypheny)-10-hydro-9-oxa-10-phospha phenanthrene-10-oxide (DOPO-HQ) were synthesized via “one-pot” melt polymerization, and then the fibers were obtained by melt spinning method. The structure and property of the copolyesters were studied elaborately by experimental characterization technique and molecular simulation method. Shear shinning behavior was observed from rheology measurement, indicating that the copolyesters had excellent melt fluidity and spinnability. The rigidity of molecular chain was efficiently improved by the phosphorus-containing monomer DOPO-HQ and naphthalene HNA units which could be reflected by the molecular simulation results as well as high Tg values. The flame retardant mechanism of the phosphorus-containing flame retardant copolyester was systematically studied via limiting oxygen index (LOI), vertical burning (UL-94) test, cone calorimetry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the copolyesters exhibit synergistic flame retardant mechanism of gas phase and condensed phase. Meanwhile, mechanical property of the as-spun fibers could be significantly improved by increasing the spinneret draw ratio (SDR) attributed to high molecular chain orientation. The maximum tensile strength of the as-spun fiber was 0.77 GPa observed for P-HNA60P20 at a relatively low SDR of 29. It was shown the unique combination of good thermal stability, spinnability as well as mechanical and flame retardant properties of the copolyesters would make them could be used as high-performance flame retardant materials.

3D Printed Drug Delivery Systems in Action-Magnetic Resonance Imaging and Relaxometry for Monitoring Mass Transport Phenomena.

The hypothesis of the study was that (1) 3D printed drug delivery systems (DDS) could be characterized in situ during drug release using NMR/MRI techniques in terms of mass transport phenomena description (interfacial phenomena), particularly for systems dealing with two mobile phases (e.g., water and low molecular weight liquid polymer); (2) consequently, it could be possible to deduce how these interfacial mass transport phenomena influence functional properties of 3D printed DDS. Matrix drug delivery systems, prepared using masked stereolithography (MSLA), containing poly(ethylene glycol) diacrylate (PEGDA) and low molecular weight polyethylene glycol (PEG) with ropinirole hydrochloride (RH) were studied as example formulations. The PEGDA to PEG (mobile phase) concentration ratio influenced drug release. It was reflected in spatiotemporal changes in parametric T2 relaxation time (T2) and amplitude (A) images obtained using magnetic resonance imaging (MRI) and T1-T2 relaxation time correlations obtained using low-field time-domain nuclear magnetic resonance (LF TD NMR) relaxometry during incubation in water. For most of the tested formulations, two signal components related to PEG and water were assessed in the hydrated matrices by MRI relaxometry (parametric T2/A images). The PEG component faded out due to outward PEG diffusion and was gradually replaced by the water component. Both components spatially and temporally changed their parameters, reflecting evolving water-polymer interactions. The study shows that dynamic phenomena related to bidirectional mass transport can be quantified in situ using NMR and MRI techniques to gain insight into drug release mechanisms from 3D printed DDS systems.

Collective dynamics of liquid sulphur across the polymerisation transition temperature probed by inelastic x-ray scattering

Inelastic x-ray scattering (IXS) experiments on liquid sulphur were carried out below (140 ∘C) and above (180 ∘C) the polymerisation temperature T λ of about 159 ∘C to investigate changes in the collective dynamics of this unique liquid, that exhibits a liquid–liquid transition. As reported earlier, broad longitudinal acoustic excitation signals were observed at both temperatures, and only the width of the quasielastic peaks slightly decreased when the temperature crossed the transition temperature. A model analysis was performed using a generalised Langevin formalism with a memory function having one thermal and two viscoelastic decay channels with the help of simple sparse modelling, and large positive deviations from the hydrodynamic sound velocity by 51%–54% were observed. The fast viscoelastic relaxation time τ µ is close to the correlation times of intermolecular stretching and bending motions of local sulphur connections in both ring and chain structures, and is similar to those of other molecular liquids. The small contrasts in the IXS spectra across the λ transition result in large changes in only the slow viscoelastic decay time τ α of the memory function. The τ α value at 140 ∘C matches the mixed internal/external torsional modes of S8 molecules well, whereas that at 180 ∘C has no corresponding molecular motion mode. The kinematic viscosity values at the Q→0 limit are much smaller than the minimum values of macroscopic shear viscosity, indicating that large changes in relaxation dynamics are expected with Q in the GHz and MHz excitation regimes.

Orientation time correlation functions up to the fourth cumulant for liquid water

The orientation time correlation functions (OTCFs) of molecular liquids are related to many experimental observations but subtle in theoretical calculations. Usually, the OTCFs at different timescales are described by distinct approaches. The OTCFs at short times were expanded into a series in an order of molecular angular velocity components, and the second cumulant (SC) of the series gave a single-frequency integral over one-mode propagation function weighted by a rotational density of states (DOS) of the liquid, whereas the OTCFs at long times displayed an exponential decay according to the Debye theory. In this paper, we derived the series of the OTCFs up to the fourth cumulant (FC), which gave a sum of twofold frequency integrals over two-mode propagation functions weighted by a product of two rotational DOSs associated with one or two molecular axes. With no need of any fitting parameter, the OTCFs calculated up to the SC and up to the FC were compared with simulation results for liquid water. With the power spectra of angular velocity autocorrelation function, which have a finite value at zero frequency, as the inputs, the OTCFs in both SC and FC schemes resulted in an exponential decay at long times, while the decay times were smaller than the simulation values. The positive results were the calculations with stable rotational instantaneous-normal-mode spectra, which have a linear behavior extrapolated to zero at low frequencies. As the stable rotational INM spectra were used as the inputs, the OTCFs in the SC scheme produced a slow power-law decay, but the OTCFs in the FC scheme captured the simulation behaviors from short to long timescale, including an exponential decay, with the decay times of the 2nd-rank OTCFs close to the simulation values.

Effect of introducing different molecular liquid solvents on electrochemical and physical properties of sodium ion conducting polymer gel electrolytes

The current investigation presents comparative studies on the effect of introducing three different molecular liquid solvents, namely ethylene carbonate: diethyl carbonate (EC:DEC), tetra ethylene glycol dimethyl ether (TEGDME), and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) on the electrochemical and physical properties of sodium ion conducting polymer gel electrolytes (PGEs) containing sodium tetrafluoroborate (NaBF4) salt, and polyvinyllidene fluoride-co-hexafluoropropylene (PVdF-HFP) polymer. The PGE, which is optimized and contains the EC: DEC solvent, has an ionic conductivity of 8.9 × 10−4 S cm−1, electrochemical stability of 4.5 V and total ion transport number of 0.99 at 30 °C. Along with conductivity studies, the X-ray diffraction studies, show that the EC: DEC raises the entropy of the PGE to its maximum value. The thermogravimetric (TGA) and differential scanning calorimetry (DSC) investigations demonstrate that electrolyte with EC: DEC exhibits a weight loss of 13 % up to 200 °C and retain the gel phase up to 140 °C. The optimized electrolyte holds promise for forthcoming sodium based electrochemical devices.

Enhancing the dielectric constant of zwitterionic liquids via dipole moment and anion chemistry

The dielectric constant is a critical parameter in many energy-related applications. Typically, increasing the dielectric constant of soft materials involves adding high dielectric constant polar liquids or inorganic fillers, but there are limitations to this approach due to safety concerns with volatile and flammable solvents and the agglomeration of inorganic fillers. An alternative approach is to add zwitterionic liquids that exhibit exceptionally high dielectric constants with negligible volatility. Here, we report the synthesis of a series of zwitterionic liquids containing an imidazolium cation, exhibiting the highest dielectric constant among all organic molecules (∼350 at 293 K). The cation–anion linkage was tailored in a wide range between three and nine carbons, rendering the zwitterion dipole from 25 to 52 D. Comparing the dielectric constant for zwitterions with different anions (i.e., sulfonylimide, sulfonate, and carboxylate) reveals the beneficial impacts of the delocalized sulfonylimide anion vs the carboxylate anion due to the enlarged molecular dipole and more homogenous liquid morphology. Molecular dipole and liquid morphology are identified as the keys to developing high dielectric constant zwitterionic liquids. The extremely high dielectric constant accessible with the proposed molecular design paves new avenues for developing high dielectric constant zwitterions that act as dielectricizers.

Effects of dynamic wetting and liquid–solid slip on self-propelled nanodrops in tapered nanochannels

Drops inside tapered microchannels exhibit self-propelled behavior, driven by the capillary pressure gradient within the drops. This driven force may be balanced by the viscous drag and the contact line drag to determine the drop displacement, in analogy to the way to predict capillary imbibition. However, how the drops move exactly with time at the nanoscale is unclear. This study employs molecular dynamics simulations to explore the dynamics of nanodrops within tapered channels with hydrophobic and hydrophilic coatings. The simulations reveal that in a hydrophobic tapered channel, drops migrate toward the wider side of the channel but may halt midway as the driving pressure approaches zero during their movements. Conversely, in hydrophilic tapered channels, drops move unlimitedly toward the channel's tip. Incorporating considerations for dynamic contact angles based on the molecular kinetic theory and liquid–solid slip, a theoretical model is derived that accurately predicts the drop displacement observed in molecular simulations without free parameters. In our simulations of drop motion in hydrophilic tapered channels, the drop displacement x is found linear with time x ∼t, as the viscous drag is dominant and the slip length is small. However, the theory further predicts that drop displacement may behave as x2 ∼t when slip length is large. Conversely, under dominant contact line drag, the theory predicts x3 ∼t for drop motion in tapered nanoslits. These findings underscore the critical influence of dynamic wetting and liquid–solid slip in precisely predicting drop motions on solid surfaces at the nanoscale.

Viscous dissipation effects on time-dependent MHD Casson nanofluid over stretching surface: A hybrid nanofluid study

The study of MHD Couple stress Casson flow of a hybrid nanofluid is paramount due to its potential applications in advanced engineering systems, particularly in enhancing thermal management and efficiency in various industrial processes. In this report, the time-dependent MHD Couple stress Casson flow of a hybrid nanofluid, considering the impact of viscous dissipation over a stretching surface is presented. The main objective of this work is to enhance the transformation heat ratio to meet the requirements of the engineering and manufacturing industries. After conducting a continuity check, the issue is analyzed by applying the principles of momentum and energy conservation. This modeling process generates nonlinear partial differential equations (PDEs), which are subsequently converted into nonlinear ordinary differential equations (ODEs) using similarity transformation and thermophysical characteristics. To solve these ODEs, the Approximate Analytical Method HAM is employed, which is specifically designed for nonlinear problems. Velocity decreases with increasing values and higher nanoparticle volume fraction further slows the velocity. Increasing the couple-stress parameter reduces velocity; increasing the Casson parameter slows the velocity profile. Increasing magnetic parameter enhances temperature profile; profile escalates with Eckert number magnitude. These findings contribute significantly to understanding the structure, interactions, and dynamics of such liquids, aligning with the focus on exploring the fundamental properties of simple, molecular, ionic, and complex liquids.

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering & Manufacturing — Part 2

Guest Editorial: Special Issue on Multi-Functional Molecular Liquids, Solids, and Crystals for Materials Engineering & Manufacturing — Part 2

Thermal steam treatment effect of metallic sodium nanoparticles for high-carbon, low permeability Domanic rocks

In a study aimed at exploring novel methods for enhancing hydrocarbon extraction from shale reservoirs, we conducted an experimental study to model the effects of thermal steam treatment on high-carbon, low-permeability Domanic shale in the presence of sodium metal nanoparticles. We characterized the mineral composition of the rock samples and evaluated the yield and quality of extracted hydrocarbons before and after treatment. Our results demonstrated an increase in extract yield with increasing treatment temperature. Notably, we observed a significantly augmented effect when we introduced sodium nanoparticles into the reaction system, enabling a 100 °C reduction in treatment temperature while maintaining comparable capabilities for extracting organic matter. It was found that the experimental products exhibited enrichment in saturated hydrocarbons, coupled with a decrease in resinous-asphaltenic substances. Within the saturated fraction, we observed a shift towards lighter alkanes and cycloalkanes (C12–C14). Moreover, it has been found that the highest yield of low molecular weight liquid hydrocarbons is acheived in the experiment involving sodium nanoparticles at 250 °C. Upon further increasing the temperature to 300 °C, we noted a decline in liquid hydrocarbon content, accompanied by an increase in gaseous hydrocarbons (C1–C4). Besides, thermal steam treatment substantially reduced the proportion of sulfur-containing aromatic compounds, such as alkylbenzothiophenes, dibenzo- and naphthothiophenes, in the aromatic fraction. The addition of sodium nanoparticles facilitated near-complete desulfurization of this fraction. Moreover, we observed a significant reduction in the total sulfur content of the extracted organic matter. Hydrothermal treatment in the presence of nanoparticles induced transformations in the kerogen structure and structural and phase changes in the mineral components of the shale.