Volume Fraction Of Solvent Research Articles

Factors increasing the hydroxycinnamic acids extraction from dandelion roots

Aim – to study the influence of extraction factors on the extraction of hydroxycinnamic acids (HCAs) from dandelion roots. Material and methods. The object of the study was air-dried dandelion roots. The HCAs content was determined using Arnov's reagent by spectrophotometric method according to the pharmacopoeial method. The influence of the nature, volume fraction of organic solvents, composition of extraction mixtures, temperature, duration, extraction frequency, medicinal plant raw material and extractant ratio, and medicinal plant raw material particle size on the HCAs yield from dandelion roots during extraction was established. Methanol, ethanol, propanol-1, propanol-2, acetone, acetonitrile, dimethyl sulfoxide, propylene glycol-1,2, ethylene glycol, glycerol and their aqueous solutions in volume fractions of 20, 40, 60 and 80 % were used as extractants. A dispersion analysis of the influence of these factors on the yield of HCAs during extraction was performed. Results. Extraction conditions providing the maximum yield of HCAs in comparison with pharmacopoeial and literary methods were experimentally developed. The conditions include: extractant – 60 % propanol-1 or a mixture of 50 % propanol-1 and 10 % acetone; extraction temperature – 80 ˚C; extraction duration – 6 hours; medicinal plant raw material and extractant ratio – 1 to 25; extraction frequency – single and medicinal plant raw material particle size – 500 μm or less. It has been proven that the physicochemical characteristics of the extractants, their volume fractions in solutions and extraction parameters have a statistically significant effect on the yield of HCAs. Conclusions. A statistically significant effect of the studied extraction factors on the yield of HCAs from dandelion roots has been proven. The developed extraction method statistically significantly increases the yield of HCAs by an average of 30% to 2.5 times in comparison with pharmacopoeial and literary extraction methods.

Effect of organic solvent additives on the enhancement of ultrasonic cavitation effects in water for lithium-ion battery electrode delamination

Ultrasonic delamination is a low energy approach for direct recycling of spent lithium-ion batteries. The efficiency of the ultrasonic delamination relies both on the thermophysical properties (such as viscosity, surface tension, and vapour pressure) of the solvent in which the delamination process is carried out, and the properties of the ultrasound source as well as the geometry of the containment vessel. However, the effect of tailoring solutions to optimise cavitation and delamination of battery cathode coatings has not yet been sufficiently investigated. Acoustic detection, high-speed imaging, and sonochemiluminescence (SCL) are employed to study the cavitation processes in water-glycol systems and identify the effect of tailoring solvent composition on cavitation strength. The addition of small volume fractions of organic solvent (ca. 10–30 vol%), including ethylene glycol or glycerol, to the aqueous delamination solution were found to significantly improve the delamination efficiency of lithium-ion battery cathode coatings due to the alteration of these thermophysical properties. However, greater volume fractions of glycol decrease delamination efficiency due to the signal-dampening effect of viscosity on the ultrasonic waves. The findings of this study offer valuable insights for optimising ultrasonic bath solution composition to enhance film delamination processes.

Ultrasensitive Solvatochirochromism of Single Benzene Chromophores.

Solvents influence the structure, aggregation and folding behaviors of solvatochromic compounds. Ultrasensitive solvent mediated chiroptical response is conducive to the fabrication of molecular platform for sensing and recognition, which however, remains great challenges in conceptual or applicable design. Here we report a cysteine-based single benzene chromophore system that shows ultrasensitivity to solvents. Compared to the ratiometrically responsive systems, the chiroptical activities could be triggered or inverted depending on the substituents of chiral entities with an ultralow solvent volume fraction (<1 vol %). One drop of dipolar solvents shall significantly induce the emergence or inversion of chiroptical signals in bulky phases. Based on the experimental and computational studies, the ultrasensitivity is contributed to the intimate interplay between solvents and chiral compounds that anchors the specific chiral conformation. It illustrates that structurally simple organic compounds without aggregation or folding behaviors possess pronounced solvatochiroptical properties, which sheds light on the next-generation of chiroptical sensors and switches.

The Influence of Physical Properties on the Membrane Morphology Formation during the Nonisothermal Thermally Induced Phase Separation Process.

The physical properties of a polymer solution that are composition- and/or temperature-dependent are among the most influential parameters to impact the dynamics and thermodynamics of the phase separation process and, as a result, the morphology formation. In this study, the impact of composition- and temperature-dependent density, heat capacity, and heat conductivity on the membrane structure formation during the thermally induced phase separation process of a high-viscosity polymer solution was investigated via coupling the Cahn-Hilliard equation for phase separation with the Fourier heat transfer equation. The variations of each physical property were also investigated in terms of different boundary conditions and initial solvent volume fractions. It was determined that the physical properties of the polymer solution have a noteworthy impact on the membrane morphology in terms of shorter phase separation time and droplet size. In addition, the influence of enthalpy of demixing in this case is critical because each physical property showed a nonhomogeneous pattern owing to the heat generation during phase separation, which in turn influenced the membrane morphology. Accordingly, it was determined that investigating spinodal decomposition without including heat transfer and the impact of physical properties on the morphology formation would lead to an inadequate understanding of the process, specifically in high-viscosity polymer solutions.

Modelling strategy for tailorable mechanics and thermochemically driven shape memory effect in amorphous polymers

Thermochemically responsive shape-memory polymers (SMPs) with biocompatibility and variable stiffness have shown great potential in biomedical applications. However, it is difficult to characterize the relaxation behavior and visco-elastoplastic deformation of this kind of SMPs due to the complex interactions between polymer segments and solvent molecules. Herein, a thermo-chemo-mechanical coupling model was proposed to predict the shape-memory behavior and thermomechanical properties of SMPs at different solvent volume fractions and temperatures. By combining the Vrentas–Duta free volume theory and the Flory-Huggins theory, the effect of free volume change on the Gibbs free energy, chemical potential, thermal expansion coefficient, and relaxation time of SMPs was investigated. Subsequently, these functions were substituted into the Maxwell and Boyce models to characterize the visco-elastoplastic mechanical behavior of thermochemically responsive SMPs under large deformation. Based on the phase transition model, the chemical plasticizing effect of solvent molecules on the glass transition temperature, shape-recovery strain, and yield strength of SMPs was further investigated. The numerical results are in good agreement with the experimental results. The proposed model is expected to provide theoretical guidance for designing SMPs with tailorable mechanics.

Evaluation of the Polarity in Binary Liquid Mixtures as a Function of Volume Fraction

The variation of solvatochromic polarity parameters as a function of mole fraction data may not represent the realistic environment of the solvatochromic probe molecule. This is because of the fact that the solvation environment of the solvatochromic probe molecules is not only determined by the number of individual solvent molecules around it but also by the size of those individual solvent molecules. In this regard we wish to understand the variation of ET N polarity parameter of binary liquid mixtures as a fuction of volume fractions. Representation of the ET N parameter as a function of volume fraction data leads to a completely different dataset for binary liquid mixtures where water is used as one of the solvents. These mixtures usually display negative deviations from linearity for the ET N values, when ET N values are plotted as a function of mole fraction values of the solvents. On the other hand, if the ET N values are plotted as a function of volume fraction values of the solvents in binary liquid mixtures containing water, these deviations are minimized to a large extent and even reversed to the positive deviations in some of these mixtures. This study gives an insight into a long lasting problem of understanding the negative deviations of the ET N values from linearity observed in binary liquid mixtures of water, as these deviations are either minimized or reversed into positive deviations when ET N values are plotted versus volume fraction of solvents. This study opens up a whole new discussion about the solvatochromic data of the solvent mixtures, whether this data must be represented as a function of mole fraction values or as a function of volume fraction of the solvents. The representation of the solvatochromic data as a function of volume fraction of solvents might lead to new insights in studying the solute-solvent interactions in binary solvent mixtures.

The importance of a good solvent of conjugated polymers for preparing dopant solution on the electrical and mechanical properties of sequentially doped conjugated polymer films

Electrical conductivity σ of the doped P3HT films is plotted against the volume fraction of a good solvent in the doping solvent blend.

Separation and recovery of nickel cobalt manganese lithium from waste ternary lithium-ion batteries

In this paper, a combination of precipitation and solvent extraction was used to study the separation and recovery of nickel, cobalt, manganese and lithium from the acid leach solution of wasted ternary lithium-ion battery cathode materials. The effects of sulfuric acid concentration, hydrogen peroxide addition, liquid-to-solid ratio, time and temperature on the metal leaching rate were optimized, and the leaching kinetic analysis showed that the metal leaching was controlled by both the diffusion of the solid-phase product layer and the chemical reaction, but the diffusion of the solid-phase product layer was dominant. Dimethylglyoxime (DMG) was first used to remove nickel as Ni-(C4H8N2O2)2, and P204 and C272 were used to extract manganese and cobalt ions from the post-nickel removal solution step by step. The effects of volume fraction of organic solvent, O/A, pH of the aqueous phase and extraction time on the extraction rate were optimized, and the extraction mechanism was analyzed by FT-IR and slope method as a cation exchange reaction, specifically the ionic exchange of metal ions with H+ in the POH of the organic solvent, and also the coordination of trace metal ions with the PO, Finally, the metals in loaded organic phase were stripped to the solution by dilute sulfuric acid which were recovered as MnO2, CoC2O4 and Li2CO3, respectively. The recovery rates for nickel, cobalt, manganese and lithium in the whole process were 96.84 %, 81.46 %, 92.65 % and 91.39 % respectively, a technical route to recover nickel, cobalt, manganese and lithium from ternary LIBs was optimized, and extractants and DMG in the process could be recycled and reused.

Pore structure design and optimization of electrospun PMIA nanofiber membrane

BackgroundPoly (m-phenylene isophthalamide) (PMIA) has been widely used in many applications due to its excellent thermal stability, flame resistance and mechanical properties. MethodsIn this study, PMIA nanofiber membranes were fabricated by electrospinning method, and then, the solvent welding was used to optimize the pore structure and mechanical strength. Effects of solvent concentration (volume fraction of solvent) and welding temperature on the PMIA nanofiber membranes’ morphology, pore structure and mechanical properties were investigated, respectively. Significant findingsThe mechanical strength and pore size was simply controlled by solvent welding and heat pressing. And the process of solvent welding and heat pressing was classifiable regulation. In addition, the separation accuracy of nanofiber membrane was controllable in the range of ultrafiltration. The mechanical strength of PMIA nanofiber membrane raised from 5.5 MPa to 99.0 MPa, while the mean pore size decreased from 459.1 nm to 33.6 nm after post-treatment. The Congo red rejection rate of PMIA nanofiber membrane after heat pressing increased from 4.9% to 94.7%, which showed excellent ultrafiltration performance.

Investigation of Solvent-Assisted In-Mold Bonding of Cyclic Olefin Copolymer (COC) Microfluidic Chips.

The bonding of microfluidic chips is an essential process to enclose microchannels or microchambers in a lab-on-a-chip. In order to improve the bonding quality while reducing the fabrication time, a solvent-assisted bonding strategy was proposed to seal the microchannels immediately after the cover sheet and substrate chip was injection molded in a single mold. Proper organic solvents were selected and the influences of solvent ratios on the surface roughness, microchannel morphology, and contact angle of microfluidic chips were investigated. When the solvent bonding was integrated in the mold, the influences of solvent volume fraction, solvent dosage, bonding pressure, and bonding time on the bonding quality were analyzed. Results show that the solvent cyclohexane needs to be mixed with isopropanol to reduce the dissolution effect. Solvent treatment is suggested to be performed on the cover sheet with a cyclohexane volume fraction of 70% and a dose of 1.5 mL, a bonding pressure of 2 MPa, and a bonding time of 240 s. The bonding strength reaches 913 kPa with the optimized parameters, while the microchannel deformation was controlled below 8%.

Analysis of the solvent strength parameter (linear solvent strength model) for isocratic separations in reversed-phase liquid chromatography

The solvent strength parameter (slope) and intercept (log kw) of the linear solvent strength model are determined for methanol-water (17 columns), acetonitrile-water (15 columns), acetone-water (7 columns), tetrahydrofuran-water (6 columns), and 2-propanol-water (4 columns) for varied compounds. It is shown that the linear region of the plots of the retention factor (log k) against the volume fraction of organic solvent (ϕ) is largely a system property independent of solute type for compounds with accessible retention factors. Solvent strength parameters for methanol (3.12 ± 0.12), acetonitrile (2.78 ± 0.18), acetone (2.71 ± 0.11), and tetrahydrofuran (2.95 ± 0.24) are assigned for siloxane-bonded silica and porous graphitic carbon columns as an average of the compound-specific experimental values. Statistical analysis indicates that the compound-specific solvent strength parameters are column dependent and limited as a general solvent property. Evaluation of the column-specific solvent strength parameters provides further evidence that the average solvent strength parameter is column dependent. The column-specific solvent strength values are compared with the hypothetical water-organic solvent distribution systems using the system constants of the solvation parameter models as variables confirming the column dependence of the solvent strength parameter. The column-specific solvent strength parameters can be predicted by the solvation parameter model with a typical deviation of about 0.12 over a range of 1.69 to 6.33 for the experimentally determined values. The intercept of the linear solvent strength model is shown to be both column and organic solvent dependent. Compound column-specific values are adequately described by the solvation parameter model. Log kw cannot be recommended as a descriptor of solute properties since it has no clear connection to a real distribution system.

Optimization of the Extraction of Total Phenols from Medicago sativa and Its Antioxidant Capacity.

The phenolic compounds from alfalfa (Medicago sativa L.) are used as antioxidants and in native medicine. They play an indispensable role in defense and signal transduction of the plant under stress conditions. This exploration of the optimal extraction parameters of the total phenols from alfalfa by using ultrasonic-assisted extraction (UAE) was aimed at providing a theoretical basis for better utilization of the total phenols in alfalfa. In this study, the effects of solvent volume fraction (A), extraction time (B), solid-liquid ratio (C) and extraction temperature (D) on the total phenols content and the total antioxidant capacity of Medicago sativa L. WL363HQ after thrips infestation were determined through single-factor experiments. Additionally, the extraction conditions of total phenols were optimized by using Box-Behnken design (BBD) of response surface methodology (RSM). The results showed that the proposed model had a good fitting degree for total phenols extraction (R2 =0.9564). The total phenols extraction from WL363HQ had significant relationship with solid-liquid ratio (C) and extraction temperature (D) (P<0.05). The influence levels of the four factors on total phenols extraction were as follows: extraction temperature (D) > solid-liquid ratio (C)>acetone volume fraction (A)>extraction time (B). The optimum extraction conditions of total phenols from WL363HQ were 50 % acetone, solid-liquid ratio of 1 : 20 (g/mL), extraction time of 45 min and extraction temperature of 60 °C. The corresponding content and total antioxidant capacity under the optimized conditions were 15.76 mg g-1 and 28.79 μmol Trolox g-1 . These results provided a new extraction method of total phenols from alfalfa.

Polymer/non-fullerene acceptor bulk heterojunction nanoparticles for efficient photocatalytic hydrogen production from water

Bulk heterojunction nanoparticles (NPs) composed of p-type polymer donor and non-fullerene acceptor are emerging photocatalysts for water splitting. Herein, bulk heterojunction NPs consisting of donor PBDB-T and non-fullerene acceptor ITIC are produced by micro-emulsion method, and are demonstrated as efficient photocatalyst to generate hydrogen from water splitting upon full spectrum illumination, with ascorbic acid as the sacrificial agent. The photocatalytic efficiency is determined by the nanoscale morphology of these bulk heterojunction NPs, which can be regulated by donor/acceptor ratio, binary solvent volume fraction, as well as surfactant content. The best-performing bulk heterojunction NPs show an outstanding hydrogen evolution rate of 257 mmol h−1 g−1, benefiting from the ideal phase separation, reasonable particle size and efficient charge separation and transfer. This work provides a rational guide for producing bulk heterojunction NPs made of organic semiconductors to reach high photocatalytic efficiency.

Harnessing aggregation-induced emission property of indolizine derivative as a fluorogenic bioprobe for endoplasmic reticulum

For fluorogenic bioimaging of the endoplasmic reticulum, a new aggregation-induced emission luminogen (AIEgen) core skeleton was conjugated with glibenclamide. Click chemistry was successfully employed for the efficient conjugation between azide-modified glibenclamide and alkyne-containing indolizine core skeleton to generate Aru68. When the volume fraction of water is increases in the solution of Aru68 in water and DMF induced aggregates formation and simultaneous increase of fluorescence intensity up to 100-fold was observed. Solvatochromism and restriction of molecular motion study by perturbation of solvent polarity index and volume fraction of glycerin in glycerin/methanol mixture provided a mechanistic insight into the turn-on phenomenon of Aru68 as AIEgen. The final bio-imaging demonstration of Aru68 in live cell conditions revealed great potential not only of the probe for wash-free bioimaging of the endoplasmic reticulum but also of the indolizine core skeleton for efficient fluorogenic bioprobe development based on aggregation-induced emission processes.

Origins of Lithium/Sodium Reverse Permeability Selectivity in 12-Crown-4-Functionalized Polymer Membranes.

Direct lithium extraction via membrane separations has been fundamentally limited by lack of monovalent ion selectivity exhibited by conventional polymeric membranes, particularly between sodium and lithium ions. Recently, a 12-Crown-4-functionalized polynorbornene membrane was shown to have the largest lithium/sodium permeability selectivity observed in a fully aqueous system to date. Using atomistic molecular dynamics simulations, we reveal that this selectivity is due to strong interactions between sodium ions and 12-Crown-4 moieties, which reduce sodium ion diffusivity while leaving lithium ion mobility relatively unaffected. Moreover, the ion diffusivities in the membrane, when scaled by their respective solution diffusivities and free ion fractions, can be collapsed to an almost universal relationship depending on solvent volume fraction.

3D bicontinuous diamond-like morphologies in thin films of soluted block copolymers.

As shown theoretically earlier via both weak segregation and self-consistent field theories, ordering of confined molten di- and tri-block copolymer morphologies in the presence of a proper 1D patterned substrate could induce the formation of 3D bicontinuous (in particular, diamond-like) morphologies (DLMs). The purpose of the present paper is to study, unlike the previous studies, how the stable DLMs are formed not in a melt but in a solution of symmetric diblock copolymers with a nonselective solvent that wets the thin film on the patterned substrate. It is shown, via a straightforward self-consistent field calculation of the total solution free energy for various competing phases, that the DLM could be formed in the solutions (with the solvent volume fraction of 0.5), which provides much faster thermodynamic equilibration of the solution as compared to the melt. The last circumstance can ease the production of stable DLMs in thin films of copolymers. The phase diagram describing the stable phases on the plane "the pattern period-the film thickness" is built.

Theoretical study of twin-column recycling chromatography with a solvent-gradient for preparative binary separations

Twin-column recycling chromatography with a solvent gradient (TCRC-SG) was investigated with the equilibrium-dispersive chromatography model. The solvent gradient caused by constant addition of a modifier between the two columns created a band compression effect to counterbalance band broadening, so that the target component band neither broadened nor shrunk. Meanwhile, band compression accelerated the separation but prevented excessive separation. Increasing the volume fraction of weak solvent in the modifier and reducing the modifier flowrate enhanced band compression and improved the separation. The effect of column efficiency (number of theoretical plates: 500–1500) on the separation was not significant. According to the separation behavior, a simple operation scheme is proposed to automatically control column switching without needing to determine the adsorption isotherm and designing operating conditions in advance. In comparison with simulated moving bed, TCRC-SG had a higher feed throughput, but consumed more solvent. The results showed that TCRC-SG is favorable for preparative separation.

An empirical model for sorption by glassy polymers: An assessment of thermodynamic parameters

A new fitting model for sorption by glassy polymers is suggested based on the Flory–Huggins (FH) equation with a composite formula for the FH interaction parameter, χ, which is applicable if sorption experimental data shows a single-maximum variation of the FH parameter. Namely, a power-like and a linear approximation is assumed for χ(φ1), as a function of solvent volume fraction φ1, before and after the point of its maximum. After determining the maximum point from a direct inspection of the sorption data, the three fitting parameters are evaluated by solving two independent least-square minimization problems. Several sorption studies of biopolymers taken from the literature show that the endset of the glass transition region is correlated with the position of the maximum of the FH interaction parameter. Based on this hypothesis and the Vrentas–Vrentas model for sorption of glassy polymers, a theoretical framework for the glass transition analysis is developed. In particular, the solvent-induced glass transition temperature variation can be estimated from the sorption isotherm as a function of the solvent content corresponding to temperatures above the temperature of sorption.

Protein-based nanoparticles synthesized at a high shear rate and optimized for drug delivery applications

This study aims to establish a method for the preparation of protein-based nanoparticles with uniform-sized nanoparticles less than 100 nm. For this, the conventional desolvation method was enhanced by applying a high shear rate. Molecular bovine serum albumin (BSA) was exploited in the modified method. The synthesis condition was optimized by the Taguchi approach. For this, an orthogonal array of L16 was used for four parameters each at four levels. Temperature, pH, agitation speed, and the volume fraction of organic solvents (ethanol/acetone) were selected as affecting parameters. The smallest size of BSA nanoparticles was obtained at pH 8, 8 °C, 66.7% (v/v) ethanol to acetone, and 7000 rpm of agitation speed (shear rate ~73304 s−1). The nanoparticles were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The BSA nanoparticles with the smallest size of 76 nm were used for the controlled release of cefazolin (Cef) as one of the most commonly used antibiotics for the treatment of bacterial infections. Also, the loading capacity and in vitro drug release kinetic behavior of the BSA nanoparticles were investigated. Amongst the adsorption equilibrium isotherms fitted to the experimental data, the Freundlich isotherm was the best isotherm with R2 = 0.97. The release kinetics of Cef was followed by the Korsmeyer-Peppas model (R2 = 0.99) revealing that the drug release is controlled by the non-Fickian diffusion-based mechanism along with polymer erosion. The kinetic data showed that about 99% of the drug is released within 42 h. According to the result of this study, BSA nano-formulation could be an encouraging carrier for antibiotics delivery.

4D Printing of Glass Fiber-Regulated Shape Shifting Structures with High Stiffness.

4D printing allows 3D printed structures to change their shapes overtime under external stimuli, finding a wide range of potential applications in actuators, soft robotics, active metamaterials, flexible electronics, and biomedical devices. However, most 4D printing uses soft polymers to accommodate large strain shape-changing capability at the price of low stiffness, which impedes their engineering applications. Here, we demonstrate an approach to design and manufacture self-morphing structures with large deformation and high modulus (∼4.8 GPa). The structures are printed by multimaterial direct ink writing (DIW) using composite inks that contain a high volume fraction of solvent, photocurable polymer resin, and short glass fibers as well as fumed silica. During printing, the glass fibers undergo shear-induced alignment through the nozzle, leading to highly anisotropic mechanical properties. The solvent is then evaporated, during which the aligned glass fibers enable anisotropic shrinkage in the parallel and perpendicular directions to the fiber alignment for shape shifting. A final postphotocuring step is applied to further increase the stiffness of the composite from ∼300 MPa to ∼4.8 GPa. A finite element analysis (FEA) model is developed to predict the influence of the solvent, fiber contents, and fiber orientation on the shape shifting. We demonstrate the anisotropic volume shrinkage of the structures can be used as active hinges to transform printed two-dimensional structures into complex three-dimensional structures with large shape-shifting and outstanding mechanical properties. This strategy for fabricating composite structures with programmable architectures and excellent mechanical properties shows potential applications in morphing lightweight structures with load-bearing capabilities.