Monosubstituted ferrocene based azobenzene liquid crystals were synthesized, in which ferrocene was flexibly attached to the mesomorphic core by click reaction. The counterpart compounds without ferrocene unit were also prepared. Two series of compounds displayed liquid crystal behaviours during heating and cooling, and had wide mesophase range. In the process of cooling, the compounds underwent a transformation from nematic phase to smectic C phase. When ferrocene was introduced into the molecule, the melting point of most compounds decreased by 30-40 °C, and the mesophase range was still as wide as 71-97 °C. These compounds emitted fluorescence at 400-550 nm and had strong absorption near 280 nm and 350 nm. Under the irradiation of 365 nm ultraviolet light, these compounds transformed rapidly from E to Z isomers, while the reverse reaction occurred slowly in the dark, especially the molecules containing ferrocene. Cyclic voltammetry studies showed that ferrocene based azobenzene derivatives exhibited one electron transfer processes with low formal redox potentials, indicating that these compounds are easily oxidized.

This paper is focused on the fabrication of novel hybrid materials based on electrospun polyamide fibers reinforced with hemp fibers (HF) dissolved in 1-ethyl-3-methylimidazolium dicyanamide ionic liquid (IL). The physical properties of the hybrid electrospun materials have been evaluated. SEM micrographs showed an interconnected structure between polyamide 6 (PA6) and IL dissolved hemp fibers. X-ray and FTIR analysis were carried out to support the SEM images. DSC and TGA profiles gave information related to the thermal stability of electrospun membrane while barrier properties analysis proved the improvement in terms of water sensitivity and reduction of water clustering phenomena. Moreover, the improvement of mechanical properties was obtained after the introduction of IL dissolved HF leading to an increase in Young’s modulus of about 640 %. The antioxidant properties of reinforced PA6 fibers were even carried out, proving an enhancement of radical scavenging activity of about 68 %. Finally, the computational work and the estimation of surface energy distribution were reported.

Except for the high adsorption capacity, the color of the adsorbent suspension and the solid-liquid separation characteristics are also essential factors for adsorption material in wastewater management. Here, a novel carboxymethyl chitosan grafted magnetic montmorillonite (CMC@MMt) adsorbent-material with large metal ions uptake capacity, transparent solution, excellent turbidity, and low cytotoxicity in human hepatic cells (HepG2 cells) was successfully synthesized by plasma technology. The adsorption performance for different metal ions, the turbidity property, and the toxicity of CMC@MMt were evaluated by systematic studies. The results indicate that adding of CMC could enhance the adsorption capacity because of NH2, COOH, and OH functional groups. Especially the turbidity property of montmorillonite was also improved due to the enlarged grain size and the polarity reduction. This research will promote the application of clay mineral-based material in environmental pollution control, such as preconcentration and immobilization of heavy metal ions.

The chain stiffness that arises from structural constraints and hindrances to internal rotation is intimately related to the macroscopic properties of polymeric materials. The main goal of this study is to examine the role chain stiffness plays in controlling polymer crystallization. Molecular simulations of the coarse-grained (CG) polymer model were used to determine the effect of chain stiffness on the structural formation upon stepwise cooling from the melts. The polyethylene (PE)-like model with different chain stiffness parameter (k) was proposed to modify the statistical weights in the rotational isomeric state (RIS) chains. The PE-like models with 0.5 < k < 1.0 and 1.0 < k < 1.5, can be regarded as more flexible to stiffer chains than normal PE (k = 1.0). Simulation results indicate that the rate of structural formation and the degree of crystallinity are increased better for normal PE chains (k = 1.0). Highly flexible chains (the case of k = 0.5) adopt larger amount of gauche conformation and have much difficulty to form the ordered structure. On the other hand, much stiffer chains (the case of k = 1.5), can still have some gauche conformation which cannot be converted to the trans state upon cooling from the melts. Our study implies that only polymers with the appropriate chain stiffness can exhibit clear evidence for crystallization.

The synthesis and phase characterization of a homologous series of 4’-alkyloxyphenyl 4-(6-(methacryloyloxy)hexyloxy))benzoate monomers have been carried out. The characterization comprises polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and temperature dependant small and wide-angle x-ray scattering (SAXS –WAXS). The X-ray data and POM images reveal both the nematic and monolayered orthogonal smectic A phase in M6En series. The monomers with a terminal chain length from five to twelve carbon atoms exhibit a wide temperature range of a stable smectic A phase with a narrow intervening nematic phase at higher temperatures. On cooling down from the isotropic phase the temperature range of the nematic and smectic A phase considerably increases. The specific features of the phase diagram and mesogenic properties of M6En series are discussed in terms of the peculiar molecular structure of these monomers.

The macromolecular crowding effect transforms the acid-denatured ferricytochrome c (cyt cIII) (UA-state) to molten-globule (MGMC-state) at pH 1.85. Crowding-induced stabilization free energy (ΔΔG) and preferential hydration ΔΓW were estimated for the UA→MGMC transition. The magnitudes of ΔΔG and ΔΓW were found to be decreased as dextran 70 (D70)> dextran 40 (D40)> ficoll 70 (F70), which demonstrates that ΔΔG and ΔΓW track the molecular size and shape of the crowder towards refolding and stabilization of UA-state to MGMC-state. Analysis of effects of crowders (D40, D70, F70) on thermal and chemical-denaturations of acid-denatured cyt cIII provided several important information, (i) macromolecular crowding increased the thermodynamic stability of acid-denatured cyt cIII, (ii) concentration, size and shape of crowder control the crowding-induced thermodynamic stabilization of MGMC-state, (iii) crowding effect increased the thermal-denaturation midpoint (Tm) with a slight change in enthalpy (ΔHm), suggesting that the steric-excluded volume effect contributes to the crowding-induced increased thermal stability of the acid-denatured protein. Analysis of entropy−enthalpy plots for D40, D70, and F70 reveals that in addition to the steric-excluded volume effect, the enthalpic contribution is also added to the macromolecular crowding-induced stabilization of acid-denatured cyt cIII. The dilute-medium, compound-crowder, purely entropic-crowder and purely enthalpic-crowder curves were obtained for acid-denatured cyt cIII for D70, D40 and F70. The crossover temperature, Tx was calculated from the dilute and compound-crowder curves. The Tx values measured for D40, D70, and F70 were found to be ∼250.15 K, 272.15 K, and 275.15 K, respectively, which suggests that the Tx value depends on the size and shape of the crowder. Furthermore, the observation of a lower value of Tx and a minor enthalpic component for D40, D70, and F70 is likely due to the formation of weaker soft interactions of acid-denatured cyt cIII with D40, D70, and F70.

This article is the second in the sequence of our investigations on morin and metallic cations:morin spectroscopic characterization, completing our first article centred on morin’s photophysical behavior. We explore, here, for the first time metallic cations:morin complexes with Ca(II), Zn(II) and Al(III) in MeOH by steady-state and picosecond time-resolved fluorescence techniques. We evidenced that the metallic cations:morin complexes could exhibit typical pico- and nanosecond time-resolved signatures. We observed that for the metallic cations, with the lowest complexation efficiency, we still see traces of the emission of the morin:solvent complex that we evidenced in our former article. Therefore, supported by steady-state and time-resolved spectroscopies, we present an argued assignment of the time-components extracted from the fluorescence decays to the main species present in solution. We investigated with more accuracy and sensitivity (by time-resolved fluorescence) the presence of cation in aqueous solutions than it was already performed in literature before. We hope that this work will stimulate the development of new methods for the detection of metallic cations in water including time-resolved fluorescence techniques.

Understanding the ionic current rectification (ICR) is crucial for elucidating the physical mechanisms of ions transport in various processes and for advancing the development of nanodevices. Using molecular dynamics simulations, we explore the properties of ionic motion in negatively charged conical nanopores with a tip radius fixed at 1.51 nm. The effects of ion transport behavior on ICR under different electric fields, angles, and cation species were studied. The rectification ratio increases linearly with an increase in angle (0°-15°), slows down and then eventually stabilizes with an increase in electric fields, and depends on the cation species being used. Our results indicate that the ion current is mainly contributed by the flow of cations in ultra-narrow nanopores. Further analysis of the ion concentration distribution reveals that the inverse ICR phenomenon is mainly caused by the cation concentration polarization at the tip under negative electric field, making cations are difficult to enter the nanopore from the tip, resulting in a decrease in ionic current. Additionally, cations entering the nanopore from the tip become trapped in the potential well of the tip at a negative electric field, leading to lower ion mobility and ionic current. Finally, it is found the difference in ICR ratio mainly results from the migration rate of cations with different nanopore angles and different ionic types. Our study provides valuable insights into the behavior of ions in ultra-narrow conical nanopores and the mechanisms behind ICR, which could guide the design and development of nanodevices that rely on ionic transport, such as biosensors and energy storage systems.

An effective fitting scheme within the thermo-viscoelastic model is proposed for estimation of dynamic eigenmodes of an ionic melt from ab initio molecular dynamics (AIMD) simulations. Dynamic eigenmodes are solutions of the generalized Langevin equation in matrix form, obtained on the basis set of eight dynamic variables. Fitting parameters are used only in the generalized hydrodynamic matrix T(k) for matrix elements involving heat density and heat current correlations only, because of huge computational efforts needed to calculate them directly in ab initio simulations. In the proposed scheme six AIMD-derived time correlation functions, three partial density-density and three partial current-current ones, are recovered by the proposed theoretical approach, which satisfies the exact sum rules up to the fourth frequency moments of partial dynamic structure factors. The suggested theoretical analysis was applied to estimation of propagating hydrodynamic and non-hydrodynamic eigenmodes in molten NaCl.

A series of shear thickening fluids (STFs) were prepared based on dispersed fumed silica in virgin polyethylene glycol (V/PEG) and modified PEGs by malonic acid (M/PEG) and tartaric acid (T/PEG). Rheological examination revealed that modification of PEG to a higher chain length of medium molecules remarkably improves STF peak viscosity and decreases the critical shear rate. High-velocity impact resistance of V/STF, M/STF, and T/STF-treated fabric was investigated at different layers and impact velocities and found significant improvement over neat fabric targets. Investigation of the results of two-layer samples showed the energy dissipation of V/STF, M/STF, and T/STF-treated fabrics at an impact velocity of 240 m/s is improved by 30.04%, 40.60%, and 46.06%, compared to the neat fabric, respectively. Furthermore, the tensile strength test revealed that these STFs fill the spaces between the fibers and make the fabric stronger and more resistant to breaking. In addition, a Linear/Nonlinear artificial intelligence regression analysis was performed. The results showed a strong correlation between composite mechanical response and speed. The proposed model can be further used to predict material behavior at other tensile speeds.

In this work, an alternative theoretical–experimental approach was combined to investigate the influence of the degree of functionalization of reduced graphene oxides (rGO) on the capacity and adsorption mechanisms of two model organic dyes. The experimental adsorption equilibrium data for methylene blue (MB) and indigo carmine (IC) were adjusted and studied using an efficient Multi-Layer Finite Model (MLFM) based on statistical mechanics. Additionally, density functional calculations (DFTB and DFT) were carried out to study the molecular interaction geometry and adsorption energies. With this approach, a greater amount of information about the adsorption process can be obtained in relation to commonly used methodologies for adsorption at a solid–liquid interface. Herein, kinetic and adsorption equilibrium experiments were conducted on rGOs prepared via thermal reduction at different temperatures (300, 700, and 1000 °C) in order to obtain very different contents of oxygenated functional groups. The highest adsorbed amounts are obtained for rGO1000, reaching 208 and 320 mg g−1 for MB and IC, respectively. The MLFM results revealed that the rGO-dye interaction occurs preferentially via π-stacking, and with the formation of up to two adsorption layers. The elimination of functional groups from the surface of rGOs is also revealed to be favorable, decreasing the adsorption energy and increasing the amount and fraction of molecules adsorbed in parallel orientation.

Natural Eutectic Solvents (NES) are a promising class of environmentally friendly liquids that offer an alternative to conventional organic solvents. To investigate their potential for extracting phenolic compounds from plant materials, we employed the COSMO-RS (COnductor like Screening MOdel for Real Solvents) computational method. Nineteen NES solvents were prepared to determine the most selective and effective solvent for extracting phenolic compounds from Teucrium chamaedrys using both theoretical and experimental evaluation. Screening of extraction efficiency was performed by quantification of individual compounds using ultra-high-performance liquid chromatography with a diode array detector and a triple-quadrupole mass spectrometer (UHPLC-DAD-MS/MS), as well as spectrophotometric assays (total phenolic content, total flavonoid content, and radical scavenging activity). In this paper, we propose a new approach to model NES properties using COSMO-RS. While the majority of previous studies have modeled these solvents as individual or pseudo-component complexes between hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA), we have developed a ternary HBD:HBA:water supramolecular complex model to represent NES solution structures more accurately. This model provides insights into the intermolecular interactions driving the extraction process and predicts extraction efficiencies that agree with experimental data. Two eutectic mixtures (choline chloride:succinic acid in molar ratio 1:1 and 20% of water (w/w) and choline chloride: glycerol in molar ratio 1:1 and 20% of water (w/w)) showed strong affinity towards phenolic compounds. Overall, our findings suggest that the ternary complex model is a more appropriate approach for modeling NES properties.

The fluorescent lapachones were obtained from lapachol, a natural product extracted from the heartwood of Tabebuia sp. (Tecoma). The extracted lapachol was oxidized and cyclized to obtain the compounds β-lapachone and nor-β-lapachone, and treatment with terephthalaldehyde led to the final products with ∼60% yield. The photophysical studies showed absorption maxima in the violet region (∼400 nm) and fluorescence emission maxima depending on the solvent, ranging from 430 to 575 nm with a relatively large positive solvatochromism, confirmed by the Lippert-Mataga plot. Theoretical calculations corroborate the experimental observations regarding the ICT mechanism. The imidazoles showed a selective response to bisulfite ion (HSO3-) over other common anions, displaying a large change in both fluorescence and absorption spectra immediately after the addition of bisulfite, proving their potential application in tracing the bisulfite in future biological systems. The binding capacity of the imidazoles with human or bovine serum albumin (HSA and BSA, respectively) is spontaneous, weak (102-103 M-1 range), and subdomains IIA (Site I) and IB (Site III) are the main binding regions for the imidazoles depending on the nature of the metabolite or drug previously complexed with the albumin structure. Overall, both albumins have the same capacity to interact with the imidazoles under study.

Oil-paper insulation is commonly used in transformers and is subject to dynamic changes in moisture content and distribution due to the influence of multiple physical fields such as temperature and electric fields. Moisture at the interface of oil-paper insulation can distort the interfacial electric field and cause insulation failure, but it is difficult to measure and characterize. In this study, molecular dynamics was used to simulate the diffusion behavior of water molecules at the interface of natural ester oil-paper insulation at temperatures ranging from 298 to 373 K, and the effect of electric fields on water diffusion was also analyzed. The results showed that without an electric field, water molecules in natural ester insulating oil tend to cluster at 298 K. Water molecules gradually diffuse towards the interface of the natural ester oil-paper insulation, but most remain at the interface and are difficult to penetrate into the cellulose insulating paper. In addition, normal diffusion is gradually enhanced at 298–328 K, reaching a minimum at 343 K. The interaction energy between water molecules and natural ester insulating oil decreases with increasing temperature, while the interaction energy with cellulose insulating paper decreases and then increases, reaching a minimum at 343 K. The combined influence of temperature and electric fields leads to an increase in the number of water clusters at the oil-paper interface. The interaction energy between water molecules and both natural ester insulating oil and cellulose insulating paper is enhanced, inhibiting the diffusion of water into the insulating paper. It was also found that the ability of water to diffuse differs significantly when the electric field direction is normal to the interface compared to when it is tangential to the interface. This is due to the fact that the water molecules when subjected to electric field action turn to polarize, and their electric field direction diffusion coefficient decreases, but still much higher than the non-electric field action direction. Further, the study found that the natural ester oil-paper insulation interface polarization is directional, and water molecules polarized in the direction normal to the insulation interface require a higher electric field strength.

Deep eutectic solvents (DESs) with outstanding environmental suitability have emerged as green alternatives to ionic liquids (ILs) and many other organic solvents. Nevertheless, their separation from reaction media and reuse is still problematic. Hence, the heterogenization of DESs on proper support can overcome their drawbacks. Herein, a DES-supported catalyst was prepared for the synthesis of organic compounds. Initially, the surface of Fe-based MOF, NH2–MIL-88B, was modified via a polymerization reaction between MOF amino groups, cyanuric chloride, and urea. Then, choline chloride (ChCl) was stabilized on the surface of modified MOF, NH2–MIL-88B-CU, through hydrogen bonding. NH2–MIL-88B-CU@ChCl as a multifunctional catalyst (Brønsted/Lewis acids and Brønsted base), with alluring attributes like environmental sustainability, chemical and thermal stability, retrievability, and reusability, was used for the one-pot three-component synthesis of spirooxindoles. Its high catalytic performance was related to a synergistic effect between actives sites of NH2–MIL-88B-CU and ChCl. NH2–MIL-88B not only provided a platform for immobilizing of ِDESs but also showed catalytic activity through Fe-oxo nodes. Quantum chemical calculations were performed to shed light on the reaction mechanism. In addition, green metrics parameters have shown that the present method is more efficient than some reported homogeneous and heterogeneous catalytic systems while providing less waste, which is vital from the viewpoint of green chemistry. The hot filtration test and the retrievability/reusability of the catalyst proved the structural stability and heterogeneous nature of the hybrid system.

In this study, a novel magnetic microbead adsorbent (M−PES−PEI) was made using magnetic iron oxide (MNPs), polyethersulfone (PES), and polyethyleneimine (PEI)to remove the lead ions (Pb2+) from drinking water. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) methods were used to analyze the M−PES−PEI microbeads. Adsorbent dosage (20 mg), contact time (90 min), and solution pH ∼ 5 as the effective parameters on experimental conditions were examined and 91% removal of Pb2+ was obtained using 50 mg of microbeads. Adsorption models based on isotherms, kinetics, and thermodynamics were used to simulate the adsorption of Pb2+ over M−PES−PEI. The pseudo-second-order as the kinetic model was fitted to the adsorption data at different times (R2 > 0.97). In the isotherm study, the Freundlich model shows a higher R2 (0.99) value than the Langmuir model at different concentrations. After 90 min of contact time at room temperature, the maximum adsorption capacity was 312 mg.g−1 with physical mechanism.

Water, as simultaneously the most intriguing and ubiquitous liquid on the planet, holds central relevance in our world – and displays a suite of fascinating anomalies. Of notable interest in this study is the leveraging of non-equilibrium molecular dynamics (NEMD) simulation to study the response of water molecules under the influence of external electric-fields while subjected to temperature changes. In particular, external static and oscillating electric fields with varying (r.m.s) intensities 0.05 V/Å and 0.10 V/Å and oscillating-field frequencies 50, 100 and 200GHz were examined to gauge the influence of supercooled and nearer-ambient temperature regions on water structure and interaction, dynamical properties, dipolar response, hydrogen-bond kinetics and lifetime. Interestingly, the impact of heating the system was accentuated with increase in the hydrogen-bond lengths, and A–D–H angles while the number of hydrogen-bonds reduced with increase in the temperature for all the fields conditions, although slight variations were observed under the influence of static and oscillating fields. Furthermore, as temperature increases, the increased rate of hydrogen-bond breakage influenced the rapid decay of hydrogen-bond lifetimes for zero- and static-field conditions, while molecular rotations caused by dipole-alignment response to the oscillating fields enhanced to a greater extent the mobility of the molecules, and also increased the rate of hydrogen-bond breakage and diffusivity due to the increased thermal motion. Moreover, the effect of increasing the temperature on the polarisation properties of the liquid weakened the hydrogen-bond network and also led to a decrease in the molecular and time response of the system’s dipole moment; higher temperature and field intensity invoked more rapid system dipolar alignment, in addition to the frequency relating to longer periods and greater intensity. With increasing temperature, the behaviour of system dynamics revealed shorter correlation times for zero-field conditions while oscillating-field with increased intensity revealed more rapid autocorrelation decay in comparison to those with reduced intensity. Indeed, the presence of much longer correlation time manifested by zero-field conditions in the supercooled temperature region evinced succinctly the lack of rotational motion that allows for more rapid decay time.

Polyacrylamide-based drag reducers are an essential component of slickwater fracturing fluids and are used to reduce friction during the fracturing process. However, the elevated temperature accelerates the mechanical and oxidative degradation of polyacrylamide, resulting in a dramatic decrease in the drag reduction capability. To improve the temperature resistance of polyacrylamide, many researchers have focused on introducing temperature-resistant functional groups into the side chains of polyacrylamide. However, the improvement in the temperature-resistance of polyacrylamide is limited. To address this problem, a novel water-in-water nanocomposite drag reducer, called ANS-PAA, was developed. ANS-PAA was synthesized by in-situ dispersion polymerization, which involved the use of amino-functionalized nano-silica, acrylamide, and 2-acrylamido-2-methylpropane sulfonic acid. The nanoparticles were linked to the polymer through hydrogen bonding and electrostatic interactions, which dramatically improved the thermal stability of ANS-PAA molecules. The drag reducer exhibits fast dissolving and strong temperature-resistant. Its dissolution time in tap water is 19 s and its drag reduction rate at 120°C is 70.18%. In addition, the nanoparticles embedded in the polymer network enhanced the strength of the structure. This study provides valuable insights into the development of drag reducers in slickwater fracturing fluids that more efficiently handle the high temperatures encountered in deep oil and gas reservoirs.

Depleting conventional fossil fuels and growing greenhouse gases have fascinated the researcher’s heed for the use of green and clean fuels. Thereby, such fuels can be obtained by blending gasoline with the oxygenated fuel additives to reduce the toxic gaseous emissions and enhance the fuel efficiency in the motor engine. In this regard, various thermodynamic properties like densities (ρ), speeds of sound (u) and refractive indices (nD) of the ternary mixture of diisopropyl ether (1) + ethanol (2) + n-octane (3) were experimentally measured at different temperatures (298.15 K to 318.15 K) and at 0.1 MPa. The excess molar volume (VmE), deviation in sound speed (Δu), excess isentropic compressibility (κsE), excess available volume (VaE), excess free length (LfE) and refractive index deviation were evaluated using their corresponding experimental data. Different correlations and analytical rules have been used for conceptual assessment of speed of sound and refractive index of mixtures. The effect of temperature on the above stated thermodynamics properties has also been investigated.

Density (ρ), speed of sound (u), and refractive index (nD) were measured for the binary mixture of diethyl ether (1) + cyclohexane, benzene, and toluene (2) systems at T= (288.15 K to 298.15 K) and 0.1 MPa. The measured data were utilized to calculate excess molar volume (VmE), deviation in ultrasonic speed (Δu), and deviation in refractive index (ΔnD). Our results illustrate that the positive value of VmE and negative value of Δu for diethyl ether + cyclohexane indicate the absence of specific interaction owing to the inert nature of cyclohexane and disruption of the dipole-dipole interactions in diethyl ether during mixing. Conversely, in diethyl ether + benzene or toluene system, the negative values of VmE and positive values of Δu suggest the presence of electron donor-acceptor interactions between the oxygen atom of diethyl ether and the π- electrons of benzene and toluene. These findings were further corroborated by the behavior of the molecular association parameter (MA), which showed that toluene exhibited the greatest value of MA and lower value of VmE compared to benzene, indicating a stronger degree of molecular association due increase in π-electron density because of the presence of electron-donating methyl group in toluene. On the other hand, cyclohexane showed the lowest value of MA, suggesting the disruption of dipole-dipole interaction in diethyl ether. Schaff’s collision factor theory demonstrated high predictive power for ultrasonic speed compared to other models. These experimental data significantly impact advancing theoretical models, process design, material development in chemical industries, and our understanding of the basic behavior of mixtures across various scientific and technical domains.