Physical-chemical Properties Research Articles

Accessing a Medicinal-Chemistry-Relevant Chemical Space with sp2–sp3 Hybrid Heterocyclic Fragments

AbstractTarget-first drug discovery relies heavily on protein structure information, which severely limits its application. In recent years, fragment-based drug Design (FBDD) has been identified as an alternative solution, where screening of smaller molecules for lower affinity allowed the use of focused libraries with a higher hit rate. It is shown that coupling an sp2-rich heteroaromatic group with a monofunctional sp3-rich core gives fragments (186 examples) with advantageous physical-chemical properties, covering a chemical space often neglected in traditional libraries.

Overlooked role of boron precursors in tuning engineered zero-valent iron to activate peracetic acid for sustainable micropollutant oxidation

This work comprehensively investigated how the characteristics of boron (B) precursors affect the catalytic activity of microscale zero-valent iron (mZVI) towards peracetic acid (PAA) activation for micropollutant degradation. Three boron precursors were introduced into mZVI by ball milling with their physical-chemical properties carefully characterized, and their ability to activate PAA comprehensively evaluated via sulfamethoxazole (SMX) oxidation efficiency. It’s found that B2O3-ZVI demonstrated the highest capability to activate PAA for SMX degradation, with kobs 2 ∼ 3 times higher than Na2B4O7-ZVI and H3BO3-ZVI. Specially, B precursors regulate the ability of mZVI to activate PAA via the following two aspects: (1) affecting the formation and content of FeB to accelerate Fe(II) regeneration; (2) increasing the hydrophilicity of the iron particles and the affinity of B-ZVI for binding PAA to different extent. This study highlights the important role of boron precursors in tuning engineered mZVI to initiate Fenton-like process for water purification.

Mathematical formulation of the physical properties of Hydrocarbon Gases and the determination of these parameters in a Gas-Condensate field in Albania

Abstract The physic-chemical properties of fluids that saturate a bed have been followed throughout the course of resource exploitation through different analyses. Fluids released from the formation over time of exploitation change due to the change in the phase state of the fluids, their material balance and energy. Determining the type of reservoir fluid and its properties, including physical properties and chemical properties, play a key role in reservoir engineering for many decisions made in the development of an oil and gas field. In this manuscript, the properties of gases are analyzed step by step in both their physical and mathematical contexts, as well as that of gas. In this context, a gas-condensate field located in Albania was taken into consideration, determining its properties through the relevant correlations and the use of different graphs both for the measured value of the initial pressure of the formation and for the different values of the pressure taken into consideration.

Antimicrobial pullulan packaging materials embedded with starch/thymol nanoemulsion via dynamic high-pressure micro-fluidization for strawberry preservation

Thymol/waxy maize starch nanoemulsion (TWSN) was successfully prepared via dynamic high-pressure micro-fluidization (DHPM) and applied in pullulan-based active food packaging material (P-TWSN). The properties of TWSN and its effect on the structural and physical-chemical properties of P-TWSN were then investigated. Concurrently, the impact of TWSN (0, 5, 15, 20, 25 mL) on the storage quality and flavor substances of strawberries coated by film-forming solution (FFS) were investigated by gas chromatography-ion mobility spectrometry (GC-IMS). The results demonstrated that the prepared TWSN exhibited remarkable storage stability, maintaining a particle size of 127.9 ± 1.02 nm and a ζ-potential of −32.4 ± 0.42 mV. As TWSN concentration increased, P-TWSN exhibited a smooth and compact morphology, characterized by the presence of bubble-like pores and granular protrusions. Additionally, the FTIR peaks corresponded to the stretching vibration of -OH group of TWSN and related materials were shifted to lower wavenumbers. Furthermore, the materials with increasing content of TWSN exhibited excellent water solubility, enlarged WVP, stable thermal property and superior antibacterial capacity against gram-positive (S.aureus) than gram-negative (E. coli) bacteria. Strawberry samples sprayed by FFS with 20 mL TWSN exhibited the slowest decline in shrinkage, weight loss, titrable acidity, highest value of firmness, total soluble solids, and lower content of ascorbic acid and viable microorganisms in comparison with other dosages. Additionally, the contents of esters and alcohols in treated strawberries reached the summit on the fourth day of storage and subsequently declined, while the ketone content exhibited a downward trend with increasing TWSN, particularly in the samples with 20 and 25 mL TWSN. The studies identified an efficient method for preparing starch-based nanoemulsion by DHPM, which could be prospective in bio-active packaging materials.

The Use of Lemongrass/Lemon Blend Essential Oil Nanoemulsions in Chewy Candy Formulations and Its Evaluation Against Streptococcus mutans and Porphyromonas gingivalis

Lemongrass (Lg) and lemon (Lm) essential oils (EOs) mainly contain citral and limonene, respectively, which are not limited to flavor for food but can also provide antibacterial activity. The information on the enrichment of these combined EOs in chewy candy products has never been documented yet. This study aimed to evaluate the physical-chemical properties and volatile compound of nanoemulsion formulations of Lg/Lm blend EOs as well as the physical-chemical properties, total plate count (TPC), and sensory acceptability of chewy candy formulated with nanoemulsions. Antibacterial evaluations against Streptococcus mutans and Porphyromonas gingivalis were performed for both nanoemulsion and chewy candy. Blending Lg and Lm EOs at ratios of Lg1.85 : Lm2.25 and Lg3.65 : Lm0.45 showed a broadly different constituent of the volatile compound than the ratio with the least amount of Lg (Lg0.05 : Lm4.05) but all the formulations possessed eugenol, β-Bisabolene, and caryophyllene oxide. The combination of Lg1.85 : Lm2.25 produced the nanoemulsion with the lowest particle size but lower zeta potential and emulsion stability. At this ratio, the significant inhibitory activity of the nanoemulsion was found to be 92.40% and 84.14% for S. mutans and P. gingivalis, respectively (p < 0.05). Its application in chewy candy formulation also resulted in the highest inhibitory activity against S. mutans (85%) and P. gingivalis (77.20%). Chewy candy formulated with Lg1.85 : Lm2.25 nanoemulsion was also found to have the lowest TPC of 3.72 log CFU/g. The overall acceptability of the chewy candy was around neutral (3.77) by panelists for its higher color score (4.73) and aroma (4.37) in average to the other samples. This study discovered the potential of Lg/Lm blend EOs nanoemulsion for enhancing the antibacterial effect and improving the texture and color of chewy candy.

Impact of seawater temperature and physical-chemical properties on sorption of pharmaceuticals, stimulants, and biocides to marine particles

Pharmaceuticals, stimulants, and biocides enter the environment via wastewater from urban, domestic, and industrial areas, in addition to sewage, aquaculture and agriculture runoff. While some of these compounds are easily degradable in environmental conditions, others are more persistent, meaning they are less easily degraded and can stay in the environment for long periods of time. By exploring the adsorptive properties of a wide range of pharmaceuticals, stimulants, and biocides onto particles relevant for marine conditions, we can better understand their environmental behaviour and transport potential. Here, the sorption of 27 such compounds to inorganic (kaolin) and biotic (the microalgae Cryptomonas baltica) marine particles was investigated. Only two compounds sorbed to microalgae, while 23 sorbed to kaolin. The sorption mechanisms between select pharmaceuticals and stimulants and kaolin was assessed through exploring adsorption kinetics (caffeine, ciprofloxacin, citalopram, fluoxetine, and oxolinic acid) and isotherms (ciprofloxacin, citalopram, and fluoxetine). Temperature was shown to have a significant impact on partitioning, and the impact was more pronounced closer to maximum sorption capacity for the individual compounds.

Recent Advances in Light Penetration Depth for Postharvest Quality Evaluation of Fruits and Vegetables.

Light penetration depth, as a characteristic parameter reflecting light attenuation and transmission in biological tissues, has been applied in nondestructive detection of fruits and vegetables. Recently, with emergence of new optical detection technologies, researchers have begun to explore methods evaluating optical properties of double-layer or even multilayer fruit and vegetable tissues due to the differences between peel and pulp in the chemical composition and physical properties, which has gradually promoted studies on light penetration depth. A series of demonstrated research on light penetration depth could ensure the accuracy of the optical information obtained from each layer of tissue, which is beneficial to enhance detection accuracy for quality assessment of fruits and vegetables. Therefore, the aim of this review is to give detailed outlines about the theory and principle of light penetration depth based on several emerging optical detection technologies and to focus primarily on its applications in the field of quality evaluation of fruits and vegetables, its future applicability in fruits and vegetables and the challenges it may face in the future.

MES surfactant-based liquid soaps added with eco-enzyme and pandan wangi leaf extract (Pandanus amaryllifolius Roxb) on physical-chemistry properties, and antibacterial activity,"

The growing demand for liquid soap has spurred innovations in soap formulations, particularly using methyl ester sulfonate (MES) as a surfactant base combined with natural ingredients like eco-enzyme and fragrant pandan leaf extract. This study aimed to determine the optimal liquid soap formulation by evaluating physicochemical properties and antibacterial activity against Staphylococcus aureus. The research was conducted in two stages. First, liquid soap was produced at different temperatures (20°C, 50°C, and 100°C) to identify the optimal temperature based on maximum lipase activity. In the second stage, various formulations were prepared, incorporating eco-enzyme and fragrant pandan leaf extract at the identified optimal temperature. The six formulations tested were: F1 (MES-based soap), F2 (20% eco-enzyme), F3 (15% eco-enzyme and 5% fragrant pandan leaf extract), F4 (10% eco-enzyme and 10% fragrant pandan leaf extract), F5 (5% eco-enzyme and 15% fragrant pandan leaf extract), and F6 (20% fragrant pandan leaf extract). The formulations were assessed for lipase activity, pH, density, and viscosity. The most effective formulation was further tested for antibacterial activity using the disc diffusion method with six treatments, including MES-based soap and controls. Statistical analysis using One-Way ANOVA revealed that adding eco-enzyme and fragrant pandan leaf extract significantly affected the soap's properties. The optimal formulation, containing 5% eco-enzyme and 15% fragrant pandan leaf extract, exhibited a lipase activity of 15,778 U/mL, a pH of 5.02, a density of 1.06 g/mL, a viscosity of 3.59 cP, and an antibacterial zone of 37.22 mm, making it the best candidate for further development

Regenerated spent graphite with enhanced pre-storage abilities of near-surface layers towards high-rate properties

Attracted by the potential value of spent lithium-ion batteries, their high effective-recycling has been devoted to numerous attentions. Unfortunately, spent graphite is always used as fossil fuel, accompanying with the serious resources wasting and carbon emission. Owing to low-cost and energy-consumption, their direct regeneration has been regarded as the next-generation key technology. Although high-temperature sintering can induce the recovering of internal structure, they still suffer from strong surface anisotropy. Herein, through the introduction of coating-layer, their infiltration abilities and isotropy are effectively improved. And, their physical-chemical properties can be recovered to that of commercial materials, containing compact-density, impurities-content and conductivities. The as-regenerated sample delivers a Li-storage capacity of 324 mA h g−1 at 1.0 C after 250 cycles. Even at high rates, their specific capacity can be still kept at about 286 mA h g−1 after 300 loops. Assisted by detailed electrochemical analysis, the pre-storage role of surface/near-surface layer is successfully confirmed, accompanied by stable charge balance. Moreover, its diffusion energy barrier of layers is further decreasing, accompanying with the considerable ion-diffusion behaviors. Therefore, the work is anticipated to provide significant surface-tailoring strategy for spent graphite, meanwhile illustrating the in-depth understanding of carbon-layers effect.

Atomic resolution map of the solvent interactions driving SOD1 unfolding in CAPRIN1 condensates

Biomolecules can be sequestered into membrane-less compartments, referred to as biomolecular condensates. Experimental and computational methods have helped define the physical-chemical properties of condensates. Less is known about how the high macromolecule concentrations in condensed phases contribute "solvent" interactions that can remodel the free-energy landscape of other condensate-resident proteins, altering thermally accessible conformations and, in turn, modulating function. Here, we use solution NMR spectroscopy to obtain atomic resolution insights into the interactions between the immature form of superoxide dismutase 1 (SOD1), which can mislocalize and aggregate in stress granules, and the RNA-binding protein CAPRIN1, a component of stress granules. NMR studies of CAPRIN1:SOD1 interactions, focused on both unfolded and folded SOD1 states in mixed phase and demixed CAPRIN1-based condensates, establish that CAPRIN1 shifts the SOD1 folding equilibrium toward the unfolded state through preferential interactions with the unfolded ensemble, with little change to the structure of the folded conformation. Key contacts between CAPRIN1 and the H80-H120 region of unfolded SOD1 are identified, as well as SOD1 interaction sites near both the arginine-rich and aromatic-rich regions of CAPRIN1. Unfolding of immature SOD1 in the CAPRIN1 condensed phase is shown to be coupled to aggregation, while a more stable zinc-bound, dimeric form of SOD1 is less susceptible to unfolding when solvated by CAPRIN1. Our work underscores the impact of the condensate solvent environment on the conformational states of resident proteins and supports the hypothesis that ALS mutations that decrease metal binding or dimerization function as drivers of aggregation in condensates.

Understanding the growth kinetics of polydopamine nanoparticles as a function of the temperature and the type of alcohol used as solvent media in their polymerization

Currently, one of the bottlenecks in the large-scale production of particles used for biomedical purposes is reproducibility achieving sizes less than 100 nm. For this reason, the main purpose of this work was to elucidate how the size of polydopamine nanoparticles (PDA NPs), which are widely used in cancer nanomedicine, was affected by several synthesis parameters to facilitate their production scaling-up. Specifically, PDA NPs growth kinetics were investigated as a function of the polymerization temperature (15–50 °C) and the type of alcohol (ethanol, 2-propanol, or a mixture of both) used to produce them, finding that an increase in temperature and the amount of 2-propanol in the solvent media allowed smaller NPs to be obtained. Based on the results achieved, a mathematical model capable of predicting PDA NP diameter as a function of the temperature and reaction time, the NH4OH concentration, and the type of alcohol used to synthesize them was proposed. Also, PDA solubility in the different media was studied to explain NP size behavior depending on the type of alcohol employed, which conditioned the formation of PDA oligomers. Finally, additional assays were conducted to confirm that an increase in the synthesis temperature did not affect some of the most important properties of PDA NPs from a biomedical point of view: their Fe3+-loading capacity and their inherent antitumor activity. Therefore, the results obtained in this research could be useful to scale-up the obtaining of 100 nm PDA NPs in a reproducible manner hereafter without significantly altering their outstanding physical-chemical properties.

Oil sands process-affected water composition effect on Henry's law constants for polycyclic aromatic compounds: Theory and experiment

Oil sands process-affected water (OSPW) is a source of atmospheric emission for polycyclic aromatic compounds (PACs), compounds known to have toxic effects on humans. Estimating emissions and assessing the chemical fate of PACs requires measured or predicted physical-chemical properties such as Henry's law constants (H), that can be used to predict chemical transfer into the atmosphere. OSPW is a complex water-based mixture that is highly variable in composition and nature and contains both organic and inorganic ions. This study uses COSMO-RS solvation theory to estimate and compare Henry's law constants for a set of PACs in both water and theoretically modelled OSPW, to assess the expected deviation that occurs from pure water H values due to the ionic content within OSPW. Experimental measurements of Henry's law constants for PACs in pure water and OSPW using EVA-coated passive dosing and sampler beads were also made in support of our theoretical predictions. For the theory work, OSPW composition data for the Athabasca oil sands in Alberta were used to model a simulated OSPW environment with realistic sodium, chloride, fluoride, sulfate, potassium, bicarbonate, and naphthenic acid concentrations. Theory results indicate that the combined presence of these ions at OSPW concentrations has a negligible effect on H values, causing on average a 3% or 0.014 log unit deviation. By comparison, temperature has a much larger influence on H values, with estimations showing an average 0.20 log unit increase for a 5 °C increase in temperature. The experimental results demonstrate that Henry's law constants can be accurately and precisely measured with this technique in pure water but with less precision in OSPW. Nevertheless, the experimental results support the conclusion that Henry's law constants for OSPW can be accurately estimated assuming a pure water phase.

Thermochemistry of Solid-State Formation, Structure, Optical, and Luminescent Properties of Complex Oxides Eu2MeO6 (Me-Mo, W), Eu2W2O9: A Combined Experimental and DFT Study.

Complex oxides Eu2MeO6 (Me-Mo, W), Eu2W2O9 were obtained by a solid-phase reaction between binary oxides. The thermodynamic and kinetic mechanisms of the reaction processes were established using a variety of physical-chemical methods. All compounds obtained in this work crystallize in the low-symmetry monoclinic system, forming complex framework structures, which determine a set of very valuable physical-chemical properties. Comparison of experimental Kubelka-Munk functions and DFT- calculated absorption spectra shows adequate agreement and reveals the origin of the fundamental absorption. In addition, the deficiency in DFT calculations in the part of mutual contribution of CTBs of Mo-O and W-O, from one side, and Eu-O contributions, from the other side, is reported. Calculations of absorption spectra are shown to be superior to band structure analysis in the determination of optical band gaps. Additionally, luminescent properties of Eu2MeO6 and Eu2W2O9 compounds were investigated. These studies provide a better understanding of the electronic and optical properties of the compounds Eu2MeO6 and Eu2W2O9, along with their potential applications in various areas.

Polyvinyl alcohol/sodium alginate-based conductive hydrogels with in situ formed bimetallic zeolitic imidazolate frameworks towards soft electronics

Bimetallic zeolitic imidazolate frameworks (BZIFs) have received enormous attention due to their unique physi-chemical properties, but are rarely reported for electrically conductive hydrogel (ECH) applications arising from low intrinsic conductivity and poor dispersion. Herein, we propose an innovative strategy to prepare highly conductive and mechanically robust ECHs by in situ growing Ni/Co-BZIFs within the polyvinyl alcohol/sodium alginate dual network (PZPS). 2-methylimidazole (MeIM) ligands copolymerize with pyrrole monomers, enhancing the electrical conductivity; meanwhile, MeIM ligands act as anchor points for in-situ formation of BZIFs, effectively avoiding phase-to-phase interfacial resistance and ensuring a uniform distribution in the hydrogel network. Due to the synergism of Ni/Co-BZIFs, the PZPS hydrogel exhibits a high areal capacitance of 630.3 mF·cm−2 at a current density of 0.5 mA·cm−2, promising for flexible energy storage devices. In addition, PZPS shows excellent mechanical strength and toughness (with an ultimate tensile strength of 405.0 kPa and a toughness of 784.2 kJ·m−3 at an elongation at break of 474.0 %), a high gauge factor of up to 4.18 over an extremely wide stress range of 0–42 kPa when used as flexible wearable strain/pressure sensors. This study provides new insights to incorporating highly conductive and uniformly dispersed ZIFs into hydrogels for flexible wearable electronics.

Activity of Membrane-Permeabilizing Lpt Peptides.

Herein, we investigated the toxicity and membrane-permeabilizing capabilities of Lpt and Lpt-like peptides, belonging to type I toxin-antitoxin systems carried by plasmid DNA of Lacticaseibacillus strains. These 29 amino acid peptides are predicted to form α-helical structures with a conserved central hydrophobic sequence and differently charged hydrophilic termini. Like Lpt, the expression of Lpt-like in E. coli induced growth arrest, nucleoid condensation, and cell membrane damage, suggesting membrane interaction as the mode of action. The membrane permeabilization activity of both peptides was evaluated by using liposome leakage assays, dynamic light scattering, and CD spectroscopy. Lpt and Lpt-like showed liposome leakage activity, which did not lead to liposome disruption but depended on peptide concentration. Lpt was generally more effective than Lpt-like, probably due to different physical chemical properties. Leakage was significantly reduced in larger liposomes and increased with negatively charged PCPS liposomes, indicating that electrostatic interactions and membrane curvature influence peptide activity. Contrary to most membrane-active peptides, Lpt an Lpt-like progressively lost their α-helical structure upon interaction with liposomes. Our data are inconsistent with the formation of membrane-spanning peptide pores but support a mechanism relying on the transient failure of the membrane permeability barrier possibly through the formation of "lipid pores".

Experimental characterization of two clay deposits blended with feldspar and quartz for building services and refractory applications

Clay deposits across the globe have variations in mineralogical compositions that elicit their use in numerous applications. In this study, two clay deposits were identified and blended with feldspar and quartz in various amounts to produce different samples of composites that could be used for applications in building services and refractories. Chemical analysis, mineralogical composition, microstructure, physical properties, and thermal behaviours were characterized. The X-ray fluorescence (XRF) analysis results show that the clays belong to the aluminosilicate group containing traces of other oxides which enhance strength and the crystallization of thermally stable phases. The XRD patterns confirmed the presence of dominant quartz with moderate to minor presence of kaolin, orthoclase, and albite. The texture of the clays showed particles of different sizes and shapes with uneven distribution. The EDX characteristic spectrum showed x-ray characteristic peaks of Si, Al, Fe, K, and O which affirmed their major oxide compositions. Physical properties results show that firing at various temperatures and blending resulted to increase in Bulk density and flexural strength while apparent porosity and water absorption decreased. The TGA, DTA, and DSC results show that the two clay minerals are thermally stable. This can be attributed to the nucleation and crystallization of refractory phases like cristobalite and mullite. Addition of feldspar and quartz was found to contribute significantly to improve the overall properties of the investigated clays. A comparison of the various results from the two clay deposits suggests that they could be suitable for building services and refractory applications.

Large-Scale Exploration of the LiSiPON System Using a High Throughput Experimental Method

Amorphous thin film materials in the LiPON(1) or LiSiPON(2) systems have been prepared for the first time in the early 1990s using magnetron sputtering. Since then, LiPON materials have been used as state-of-the-art solid electrolytes into all-solid-state thin film micro-batteries thanks to their outstanding properties (electrochemical stability vs Li°, wide electrochemical stability window of ~[4-0] V vs. Li+/Li0, isotropic and homogeneous medium, beneficial mechanical properties(3), very low electronic conductivity). The ionic conductivity of LiPON prepared from Li3PO4 targets remains rather moderate, reaching a maximum of 3.10-6 S.cm-1 at room temperature. However, it has recently been demonstrated that the introduction of SiO2 as a second glass former can increase this value up to 2.10-5 S.cm-1, and also that the ionic conductivity of these compounds does not increase steadily with their Li content.(4)This highlights the convoluted effects of mixed formers(5) (Si, P, B...), mixed anions(6) (O, N, S...) and Li concentration on the ionic conductivity. Nevertheless, the latter are usually observed on limited series of compositions, and barely not studied on large sets of samples, which can limit the understanding of composition-structure-conductivity relationships.In this context the aim of our work was to build a High Throughput Screening (HTS) approach to explore the LixSiyPzOuNw system as a case study (Fig.1). Indeed, HTS approaches aim to accelerate material breakthrough discovery, and to understand beyond the material mechanisms. In material science, the goal is to accelerate the discovery of new keys organic, inorganic or composite materials. It may also bring beyond ‘classical’ iterative method regarding the study of complex systems (ternary, quaternary...)(7). To do so, wide ranges of material libraries are synthesized, prior to be tested through an automated characterization workflow.Our specific approach starts with the preparation of material libraries by combinatorial synthesis using magnetron co-sputtering with tilted targets, then goes through automated and fast characterizations targeting specific properties, relevant to its application as ionic conductor.Deposition of thin films displaying composition and thickness gradients at the surface of a 4’’ silicon substrate is achieved by co-sputtering three target materials in a pure Ar or N2 atmosphere. Deposition through a shadow mask allows to discretize the continuum and to prepare a library of 76 separate LixSiyPzOuNw samples in one experiment. Then, by tuning the sputtering parameters (i.e discharge gas, gas pressure, incident power, target tilt, target-to-substrate distance,...) different compositional domains can be explored.Relevant automated characterization techniques are then applied to the material library spread on the 4’’ substrate. For the assessment of these amorphous ionic conducting films, dimensional (thickness), physical-chemical (composition & local structure) and functional properties (ionic/electronic conductivities) are studied.In this sequence, determining the composition of the thin film is a real challenge due to a number of requirements :(i) light elements analysis, especially lithium; (ii) need of localized analysis (mapping) on few mm² over large substrate (4” wafer); (iii) scarce material quantity available (~ μg) and finally (iv) fast analysis. Over lab-scale techniques available, only Laser Induced Breakdown Spectroscopy technique (LIBS) seems to fulfil all these requirements. To this purpose, LIBS is developed as a HTS mapping technique for chemical analysis. A sample calibration approach is implemented through coupling with robust chemical analysis techniques (RBS, NRA, ICP-OES, SEM-EDS).In short, this specific HTS procedure will be discussed and results about composition-structure-conductivity relationships in the LiSiPON system will be presented (Fig.2).References J. B. Bates et al., J. Power Sources. 43, 103–110 (1993).N. J. Dudney, J. B. Bates, J. D. Robertson, J. Vac. Sci. Technol. A. 11, 377–389 (1993).A. S. Westover et al., Chem. Mater. 35, 2730–2739 (2023).T. Famprikis, J. Galipaud, O. Clemens, B. Pecquenard, F. Le Cras, ACS Appl. Energy Mater. 2, 4782–4791 (2019).Y. Su et al., Phys. Status Solidi B. 254, 1600088 (2017).N. Mascaraque, J. L. G. Fierro, A. Durán, F. Muñoz, Solid State Ion. 233, 73–79 (2013).E. J. Amis, X.-D. Xiang, J.-C. Zhao, MRS Bull. 27, 295–300 (2002). Figure 1

Comparative Investigation of Large-Scale Cells of Supercapacitors Using Low-Temperature Electrolytes

The implementation of the concept of sustainable development for humanity, the advancement of alternative energy, hybrid and electric transport, and backup power supply systems, necessitate the creation of efficient energy storage devices. Such systems include lithium-ion, nickel-metal hydride, and redox flow batteries, where Faraday processes play a crucial role in energy storage mechanisms. One notable advantage of double-layer supercapacitors (SCs) as energy storage devices is the absence of Faraday processes during charge and discharge [1,2]. Moreover, the absence of Faraday processes, the rate of which sharply decreases with decreasing temperature, makes SC cells practically the only devices where power and energy features can potentially be maintained at a sufficient level at extremely low temperatures, down to minus 70-80°C [3]. The demand for developing energy storage systems capable of operating at extreme temperatures without extensive thermal control, such as space avionics systems, electric aircraft, uncrewed aerial vehicles, and electric and hybrid electric vehicles, is growing.Various methods have been adopted today to improve the performance of supercapacitors at low temperatures [4,5]. The central aspect in this direction is electrolytes, which have the most critical impact on the supercapacitor performance at these temperatures. While many investigations have been conducted on laboratory cells, a comparative analysis of the electrochemical characteristics of cells based on the developed electrolytes (non-aqueous electrolytes) was carried out to understand the correlation between laboratory and large-scale manufactured SC cells.The electrolyte mixture was prepared using organic substances: acetonitrile (AN), ethyl acetate (EA), toluene (TL), diethyl ether (DE), and vinylene carbonate (VC). A 1.2 M solution of salt TEMA TFB was used to prepare the electrolyte. Test electrolyte mixtures were prepared by adding the test additive in the amount of 5, 10, 15, and 20 vol% for DE and TL and 0.1, 1, 3, and 5 vol% for VC to the AN: EA (3:1 by volume %) mixture. These co-solvents were chosen due to their low melting point, relatively low viscosity, and moderate dielectric constant values.A comprehensive investigation of the physical-chemical and electrochemical properties demonstrates that additives to the electrolyte mixture can extend the lower boundary of the operating temperature range down to −68°C, providing good electrochemical characteristics of the cells: capacitance and stability during long-term cycling [6].To understand the behavior of developed electrolytes in large-scale SC cells, manufactured large-scale SC cells (LSC) with a standard initial capacitance of 1500F were used. Figure 1a shows the capacitance change of large-scale SC cells based on electrolyte mixture AN: EA (3:1), AN: EA (3:1) +3%VC, AN: EA (3:1) +10%DE, and AN: EA (3:1) +10%TL at +25°C. It is evident that the capacitance of LSC-based SC is nearly maintained for more than 1000 charge-discharge cycles at a temperature of +25°C, demonstrating better performance than laboratory cells. Equivalent measurements were also carried out on the self-discharge of LSC-based SC cells (Fig. 1d), showing only a slight voltage drop for just over 2 days.This behaviour indicates high resistance to various electrochemical processes, such as electrochemical decomposition of the activated electrode material and electrolyte compound,corrosion of the current-collector material,undesirable Faraday redox processes. Notably, the leakage current for large-scale cells is lower than for small (laboratory) cells, enhancing the capacitance retention ability for large-scale cells. Figure 1. Cycle-life stability (a, b, c) and self-discharge behavior (d) of the LSC cells based on electrolyte mixtures at temperatures of 25 °C (a, d), -60 (b) and -65 (c).For all samples, an increase in capacitance is observed as the number of charge-discharge cycles increases (Fig.1). This is likely due to the high current value (50A) used for large-scale cells, causing Joule heating in the cell structures, and increasing the temperature of the electrolyte mixture by several degrees.Tests of the developed electrolytes as part of laboratory SC cells and large-scale industrially produced SC cells confirmed their high resource stability during 10,000 cycles of continuous charge-discharge at a current density of 1.5 A/g, including at a temperature corresponding to the upper limit of the operating temperature range. Additionally, the resistance of SCs with these electrolytes to self-discharge was demonstrated, showcasing the possibility of a "cold start" of SC elements at a temperature of –60 °C.

Changing the Linking Functionality in a Triblock Co-Polymer for Electrolyzer or Fuel Cell Membrane or Ionomer for Chemical Stability Improvements and Potentially Other Consequences.

We have developed a versatile scalable triblock polymer system for anion exchange membrane (AEM) based electrochemical energy conversion devices. This system is uniquely suited to solving both the membrane and ionomer challenges for the commercialization of AEM water electrolysis or fuel cells. Using our advanced fundamental understanding of AEMs based on our work which began in 2010, we can design systems from first principles to match the needs of the device. A triblock ABA polymer is readily fabricated that has both chemical and mechanical stability. The synthesis of these systems is robust, high yield and amenable to high volume production. It utilizes a novel dual chain transfer agent to mediate the chain-transfer ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) or the polymerization of isoprene (IP) to give the hydrophobic B block of the polymer. This is followed by the reversible addition-fragmentation chain transfer radial polymerization of chloromethylstyrene (CMS). The polyCMS (pCMS) blocks are then quaternized with an amine to give the cationic hydrophilic A block. Before quaternization the B block is hydrogenated to give either semi-crystalline polyethylene (pE) or amorphous polymethylbutylene (pMB) from pCOE and pIP respectively. The obvious achilles heal in this system from a chemical durability standpoint is the linking ether functionality between the hydrophobic and hydrophilic blocks. The material we have synthesized to date have exceptional chemical and mechanical stability. It performs very well in ex-situ testing with KOH solutions and in device testing we have demonstrated >500 h at 50°C in water electrolysis in 5 cm2 cells in 1M carbonate electrolyte at 0.5 A cm-2. We attribute the chemical stability to the fact that we post quaternize the membrane to give methylpipiridinium cations and we assume that this reaction does not fully penetrate down the hydrophilic chain. This leaves a hydrophobic un-quaternized region close to the hydrophobic block that does not allow access to the ether linkage by the hydrated hydroxide anion. Recently a new approach to the telehelic mid block pCOE has been reported that has no ether linkages and allows the hydrophobic outer blocks to be linked by a methylene linker. This gives use an opportunity to directly contrast the chemical stability of two identical triblock co-polymers one with an ether linkage and one with a methylene linkage between blocks. In this presentation we will show the results from ex-situ chemical stability test one at low temperatures and higher hydroxide concentration and one at higher temperature and lower hydroxide concentration. There are many examples in polymer electrolyte chemistry where a simple change leads to unintended consequences. The geometry of the ether linkage versus the methylene linkage will change the way that the polymer chains will organize and entangle in ways that are not currently predictable. To probe the mechanical, chemical and morphological difference between these two polymers we will fully characterize and contrast both polymers physical chemical properties including water uptake, ionic conductivity, DSC, TGA, tensile strength and morphology through SAXS, WAXS and HRTEM. Data for the two polymer membranes will also be contrasted and compared in small laboratory 5 cm2 single cells for both electrolysis in dilute carbonate and H2/O2 fuel cells using conventional catalysts.

Preparation and property study of sawdust-modified cement mortar

Sawdust, a solid waste generated during stone processing, poses a serious threat to the environment with its untreated accumulation. This paper first analyzes the chemical composition and physical properties of sawdust, and discusses its mechanism of action in cement mortar. By systematically optimizing the blending ratio and modification method of sawdust, the sawdust-modified cement mortar with excellent performance was prepared. This study evaluates the key performance indicators of sawdust-modified cement mortar, such as compressive strength, flexural strength, and durability, through a series of experiments. The experimental results indicate that the incorporation of an appropriate amount of sawdust significantly enhances the mechanical properties of cement mortar, while also improving its durability, particularly in terms of freeze-thaw resistance. Microstructural analysis reveals the mechanism by which sawdust improves the pore structure of cement mortar; the active components in the sawdust react with the hydration products of cement, resulting in the formation of crystalline structures with higher strength.Therefore, the use of sawdust as a modifier in cement mortar can improve its mechanical properties and durability, while simultaneously reducing the accumulation of solid waste and promoting the sustainable development of building materials.