Diglyme Research Articles

Tuning local charge polarization of covalent organic frameworks for enhanced photocatalytic uranium (VI) reduction

The introduction of local charge polarization is an effective strategy to improve the electrostatic potential difference of covalent organic frameworks (COFs) photocatalysts. Herein, BPDA-COF with donor–acceptor (D-A) structure was firstly synthesized by using triphenyl-triazine and biphenyl monomers. Subsequently, the hydroxyl and bis(2-methoxyethyl)ether (PEO)-chains with increasing local charge polarization were introduced to synthesize DHBD-COF and PEO-COF, respectively. PEO-COF with electronegative and flexible PEO-chains created a strong local charge polarization to enhance the electrostatic potential differences, thus promoting the spontaneous transfer of electrons and inhibiting the recombination of electrons and holes. Furthermore, the super-hydrophilic PEO-chains provided super-strong uranium mass transfer capacity. Benefiting from these, PEO-COF exhibited excellent photocatalytic uranium reduction capabilities (1427.9 mg g−1). This work provides a novel insight to adjust the local charge polarization at the molecular level and broadens the strategy of photocatalytic reduction of U(VI) with COFs.

Synergistic Integration of Physical Embedding and Machine Learning Enabling Precise and Reliable Force Field.

Machine-learning force fields have achieved significant strides in accurately reproducing the potential energy surface with quantum chemical accuracy. However, this approach still faces several challenges, e.g., extrapolating to uncharted chemical spaces, interpreting long-range electrostatics, and mapping complex macroscopic properties. To address these issues, we advocate for a synergistic integration of physical principles and machine learning techniques within the framework of a physically informed neural network (PINN). This approach involves incorporating physical knowledge into the parameters of the neural network, coupled with an efficient global optimizer, the Tabu-Adam algorithm, proposed in this work to augment optimization under strict physical constraint. We choose the AMOEBA+ force field as the physics-based model for embedding and then train and test it using the diethylene glycol dimethyl ether (DEGDME) data set as a case study. The results reveal a breakthrough in constructing a precise and noise-robust machine learning force field. Utilizing two training sets with hundreds of samples, our model exhibits remarkable generalization and density functional theory (DFT) accuracy in describing molecular interactions and enables a precise prediction of the macroscopic properties such as the diffusion coefficient with minimal cost. This work provides valuable insight into establishing a fundamental framework of the PINN force field.

A novel ionic liquids phase change absorption system for carbon dioxide capture and utilization

In order to achieve low cost, and reduce energy consumption during regeneration, a novel ionic liquid phase change absorbent composed of tetraethylenepentamine [TEPA] imidazole [Im] and diethylene glycol dimethyl ether (DGME) and water was designed for CO2 capture applications. The absorbent [TEPAH][Im]+DM+H2O can achieves a CO2 absorption capacity of 2.08 mol CO2/mol ILs, the rich phase volume accounts for 15.6 vol%, and the mass fraction of CO2 is 99 %, this greatly reduces the regenerative volume of the absorption system, showing the potential of energy saving and emission reduction. After five absorption–desorption cycles, the regeneration efficiency of the system remained above 96 %. The CO2 capture mechanism was analyzed using both 13C NMR spectroscopy and density functional theory (DFT) calculations to elucidate its underlying processes. The cation [TEPAH]+ and the anion [Im]- each undergo a reaction with CO2 to produce carbamate, followed by hydrolysis of carbon dioxide to yield carbonate. The absorption system’s phase transition behavior primarily arises from variations in CO2 product solubility across solvents. Moreover, the ionic liquid facilitated the conversion of CO2 into quinazoline-2,4 (1H, 3H)-dione with a remarkable yield of 98 %. Even after five cycles, the ILs maintained substantial catalytic activity.

An in situ gel electrolyte for the facile preparation of high‐safety Li‐S battery

AbstractLithium‐sulfur (Li‐S) battery shows promising development potential in secondary lithium‐ion batteries. However, the shuttle effect of polysulfides, uncontrollable lithium dendrite growth, and safety hazards in conventional liquid electrolytes limit the popularity of Li‐S batteries in the future commercial market. In this work, a high‐performance gel electrolyte (GPE) was prepared in situ by initiating the ring‐opening polymerization of 1,3‐dioxolane (DOL) with aluminum trifluoromethanesulfonate (Al(OTf)3) and using diethylene glycol dimethyl ether (DME) as a plasticizer, which can effectively improve the interfacial compatibility between sulfur cathode and the electrolyte, as well as the stability of lithium anode. The electrochemical performance of the poly‐DOL (PDOL) GPE was optimized by adjusting the concentration ratio of the initiator. When the concentration of Al(OTf)3 is 4 mM, the PDOL GPE has a high ionic conductivity up to 3.81 × 10−4 S cm−1 and a lithium ion migration number of 0.57. The assembled quasi‐solid‐state Li‐S batteries shows an initial discharge specific capacity of 908.1 mAh g−1 at 0.1 C with a capacity retention of 68% after 240 cycles, and its average Coulombic efficiency is maintained at 96.1%. This gel electrolyte design provides a feasible practical idea in quasi‐solid‐state Li‐S batteries.

Effect of Temperature on Faradaic Efficiency and SEI Formation in Lithium Mediated Nitrogen Reduction

Lithium-mediated nitrogen reduction (Li-N2R) can be distributed and powered by renewable energy, making it a sustainable ammonia production alternative to the Haber Bosch process. While Haber Bosch is responsible for 1.3% of CO2 emissions yearly and requires centralized facilities with high temperatures and pressures, Li-N2R works at near-ambient conditions and therefore allows for decentralized production.1 First, lithium (Li+) ions electroplate as lithium metal on the working electrode. Second, the deposited lithium reacts with N2 gas to form lithium nitride (Li3N). Lastly, Li3N reacts with a proton source to form ammonia (NH3) (Figure Right).During Li-N2R, the NH3 selectivity is controlled through the mass transport of N2, Li+, and protons to the working electrode electrode (WE). The transport of these species is limited by the solid electrolyte interface (SEI), a passivation layer formed on top of the WE.2 The thickness and ratio of organic and inorganic species in the SEI change at different cycling temperatures, thus affecting the rates of transport between charge and uncharged species traveling to and from the electrode. Here, we study the impacts of temperature on FE and SEI composition in 1M LiBF4 in both diglyme (DG) and tetrahydrofuran (THF) with a 1v% ethanol (EtOH) proton source (Figure Left). Using ion chromatography (IC), nuclear magnetic resonance (NMR), and inductively coupled plasma mass spectrometry (ICP-MS) on the SEI dissolved in D2O, we quantify the SEI species formed at different cycling temperatures. Our correlation of temperature and SEI compositions to FE provide opportunities to engineer the SEI for improved Li-N2R FE and stability. 1J. W. Erisman et al., Nat. Geosci 2008. 1, 636–639 2K. Steinberg et al., Nat. Energy 2022, 8 (2), 138 Figure 1

Temperature Dependence of SEI Formation and Faradaic Efficiency in Electrochemical Lithium Mediated Nitrogen Reduction to Ammonia

Lithium-mediated nitrogen reduction (Li-N2R) is a promising electrochemical ammonia production alternative to the Haber Bosch process, a process responsible for 1.3% of CO2 emissions yearly.1 While Haber Bosch requires high temperatures and pressures in large centralized facilities, Li-N2R works at near-ambient temperatures and pressures allowing for decentralized production and can be powered by renewable electricity sources. In Li-N2R, Li ions are plated as Li metal on the working electrode, which then reacts with N2 gas to form lithium nitride (Li3N). Lithium nitride reacts with a proton source to form ammonia (NH3) (Figure left).Past research indicates that the solid electrolyte interface (SEI) formed in the electrochemical system has a large impact on the NH3 faradaic efficiency (FE) of the cell.2 Variations in the temperature during cell cycling can influence both the thickness and composition of the SEI. This, in turn, alters the kinetics of species transport to and from the electrode. Consequently, SEIs formed at different temperatures lead to varying proportions of products in the reaction, and are a helpful tool to tune the system towards NH3 selectivity. We elucidate temperature effects on SEI formation and FE for electrolytes with 1M LiBF4 in two common solvents, Tetrahydrofuran (THF) and diglyme (DG), with a 1v% ethanol (EtOH) proton source (Figure right). We also confirm the validity of our results with an Ar control. By dissolving SEI species in a D2O rinsate, we can quantify the composition of the SEI formed at different temperatures using a combination of nuclear magnetic resonance (NMR), inductively coupled plasma mass spectrometry (ICP-MS), and ion chromatography (IC). With our strategy, we correlate SEI composition trends with changes in FE, and provide pathways towards engineering the SEI for enhanced Li-N2R FE to NH3 and improved electrolyzer lifetime. 1J. W. Erisman et al., Nat. Geosci 2008, 1, 636–639 2K. Steinberg et al., Nat. Energy 2022, 8 (2), 138 Figure 1

The influence of molecular structure on the oxidation reactivity of long-chain ethers: Experimental observation and theoretical analysis

Long-chain ethers have been proposed as promising biofuels for advanced combustion methods, yet their low-temperature oxidation (LTO) characteristics remain poorly understood. In this study, the LTO reactivities of n-heptane and five long-chain ethers with different structures, including dibutyl ether (DBE), diethylene glycol dimethyl ether (DGM), polyoxymethylene dimethyl ethers (PODE), 1,2-dimethoxyethane (1,2-DME), and dipropyleneglycol dimethyl ether (DPGDE) are investigated using a cooperative fuel research (CFR) engine, which is closer to the actual internal combustion engine operating environment. Products formed from LTO of ethers and n-heptane are investigated over a wide range of compress ratios (CRs), and their relationship to the global oxidation reactivity is suggested based on the quantum chemistry calculation. The presence of oxygen atoms in long-chain ethers significantly enhances oxidation reactivity, with the global oxidation reactivity ranking as follows: DGM > DPGDE > 1,2-DME > DBE > PODE > n-heptane. The key intermediate species generated during the LTO of n-heptane include aldehydes, ketones, and cyclic ethers, while oxygen atoms in ethers facilitate the formation of acids. The species pathway analysis and quantum chemistry calculations reveal that (1,5) and (1,6) H-transfers of alkylperoxy radical (ROȮ) are critical chain-propagation channels, playing pivotal roles in the LTO process. The impact of oxygen on oxidation reactivity can be attributed to two primary factors: accelerating the H-abstraction of ȮH and H-transfer of ROȮ by weakening the neighboring C-H bonds, and enhancing the branching ratio of H-transfer of ROȮ. The arrangement of two oxygen atoms between every two carbon atoms (–OCH2CH2O–) is optimal for oxidation reactivity, while the arrangement of oxygen and carbon (–OCH2OCH2–) weakens the oxidation activity due to fewer available hydrogens for H-transfer. The methyl group in branching-chain, exhibit reduced oxidation reactivity due to the strength of C-H bonds. Additionally, for ethers with the same structure, a longer carbon chain allows for more available hydrogens, resulting in stronger oxidation reactivity.

A Novel Phase Change Absorbent for CO2 Capture with Low Viscosity and Effective Absorption–Desorption Properties

Excessive carbon dioxide (CO2) emissions can lead to environmental problems, and the use of phase change absorbents for CO2 capture has received much attention due to their excellent absorption and desorption properties. Herein, a novel liquid–liquid phase change absorbent consisting of N‐aminoethylpiperazine (AEP), diethylene glycol dimethyl ether (DEGDME), and H2O is utilized. Under the optimal absorption conditions, the absorption capacity is 1.23 mol CO2·mol−1 amine. The rich‐phase viscosity of the AEP/DEGDME/H2O solution is only 6.2 mPa s−1, and the rich phase‐to‐volume ratio is 52.7%, which is suitable for industrial applications. After five cycles of absorption–desorption experiments, the cyclic capacity reaches 0.62 mol CO2·mol−1 amine. However, it should be noted that this leads to an increase in the viscosity of the solution with time. The 13C Nuclear Magnetic Resonance characterization is used to analyze the material distribution and phase separation mechanism, and it is found that during the absorption process, the carbamate and carbonate products generated by the reaction of the amino group in the AEP with CO2 are mainly located in the rich phase, while the DEGDME and H2O mainly remain in the lean phase. In the desorption process, most of the absorbed products are decomposed, and the regeneration efficiency is 66.8%. Through the regeneration energy consumption experiment, when the regeneration efficiency is 56%–67%, the total regeneration energy consumption is 2.71–2.89 GJ t−1 CO2, which is 0.91–1.09 GJ t−1 CO2 lower than that of the regeneration efficiency of 30 wt% MEA solution at 63%, which indicates that this absorbent has certain energy‐saving advantages.

Investigation of the effect of ether oxygenated additives on diesel engine performance, combustion, and exhaust emissions - An experimental approach

Conventional energy sources, including diesel and petrol, are decreasing day by day, while their reserves are limited. However, it is difficult to find alternative fuels to replace them. Hence, to fulfill the growing energy demand and reduce environmental emissions, it is vital to find a wide variety of oxygenated compounds to conventional diesel fuels that show low emission potential from transport engines. In this research, we investigated diesel engine performance, combustion, and exhaust emissions with the addition of 10 %, 15 %, 25 %, and 30 % of three different oxygenated blends, including Diethylene Glycol Dimethyl ether (DGM), Di-n-Butyl Ether (DBE), and Tripropylene-Glycol Monomethyl ether (TPGM). This paper presents the brake-specific fuel consumption (BSFC), Brake Thermal Efficiency (BTE), Brake Mean Effective Pressure (BMEP), and Brake Specific Energy Consumption (BSEC) for these fuel blends. The generated emissions of carbon dioxide (CO2), Carbon Monoxide (CO), and nitrogen oxide (NO) were quantified for four different engine speeds of 1500, 1800, 2000, and 2400 rpm for neat (100 %) oxygenated blends. This research also shows the in-cylinder pressure and heat release rate (HRR) of these three oxygenated blends. The outcome of this paper will help future researchers to develop automobiles and vehicles for oxygenated blends with conventional fuels.

Engineering of Aromatic Naphthalene and Solvent Molecules to Optimize Chemical Prelithiation for Lithium-Ion Batteries.

A cost-effective chemical prelithiation solution, which consists of Li+, polyaromatic hydrocarbon (PAH), and solvent, is developed for a model hard carbon (HC) electrode. Naphthalene and methyl-substituted naphthalene PAHs, namely 2-methylnaphthalene and 1-methylnaphthalene, are first compared. Grafting an electron-donating methyl group onto the benzene ring can decrease electron affinity and thus reduce the redox potential, which is validated by density functional theory calculations. Ethylene glycol dimethyl ether (G1), diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether solvents are then compared. The G1 solution has the highest conductivity and least steric hindrance, and thus the 1-methylnaphthalene/G1 solution shows superior prelithiation capability. In addition, the effects of the interaction time between Li+ and 1-methylnaphthalene in G1 solvent on the electrochemical properties of a prelithiated HC electrode are investigated. Nuclear magnetic resonance data confirm that 10-h aging is needed to achieve a stable solution coordination state and thus optimal prelithiation efficacy. It is also found that appropriate prelithiation creates a more Li+-conducing and robust solid-electrolyte interphase, improving the rate capability and cycling stability of the HC electrode.

Dendrite/Volume Expansion-Free Lithium Deposition Inside the Enclosed Nanoscale Space of Electrochemically Modified Graphite

Though over-lithiation of graphite can increase the initial specific capacity of the anodes, the cycling stability is unsatisfactory as metallic lithium depositing on the surface of graphite has poor reversibility. In this work, we utilize electrochemical co-intercalation of Li+ and diethylene glycol dimethyl ether (DEGDME) to prepare [Li-DEGDME]+-graphite co-intercalation compounds ([Li-DEGDME]-Gr) from pristine graphite. The expanded d-spacing and abundant cross-layer voids in the interlayer structure of [Li-DEGDME]-Gr owing to the co-intercalation of [Li-DEGDME]+ complex ions and parasitic chemical reactions between solvent molecules and graphene layers promotes the migration of bare Li+ and provides sufficient interior space for extra lithium-storage. As a result, a much higher lithium-storage capacity of 810 mAh g−1 can be successfully achieved. The extra lithium-storage is proved to originate from the deposition of lithium metal inside the enclosed nanoscale space of the as modified graphite, which inhibits the formation of lithium dendrites, isolates lithium metal from electrolytes and avoids volumetric expansion, enabling the [Li-DEGDME]-Gr electrodes to exhibit better cycling stability with high specific capacity. This work proposes a new strategy to enhance the reversibility of lithium metal plating/stripping by accommodating lithium deposition inside modified carbon materials, thus effectively increasing the reversible capacity of graphite-based anode materials.

Influence of glycol ether additive with low molecular weight on the interactions between CO2 and oil: Applications for enhanced shale oil recovery

The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO2 enhanced oil recovery (EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO2 and oil were investigated here. The solubility of glycol ether additive in CO2 was firstly characterized. Then, the effects of glycol ether additives on the interfacial tension (IFT) between CO2 and hexadecane and the volume expansion and extraction performance between CO2 and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether (DEG), triethylene glycol dimethyl ether (TEG), and tetraethylene glycol dimethyl ether (TTEG) all have low cloud point pressure and high affinity with CO2. Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO2 by more than 30.0%, while an overall reduction of 20.0%–30.0% for TEG and 10.0%–20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO2 for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO2 have potential application for EOR. This study can provide theoretical guidance for the optimization of CO2 composite systems for oil displacement.

Monolithic Interphase Enables Fast Kinetics for High‐Performance Sodium‐Ion Batteries at Subzero Temperature

AbstractIn spite of the competitive performance at room temperature, the development of sodium‐ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low‐concentration electrolyte, consisting of 0.5M NaPF6 dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature. Such an electrolyte generates a thin, amorphous, and homogeneous cathode/electrolyte interphase at low temperature. The interphase is monolithic and rich in organic components, reducing the limitation of Na+ migration through inorganic crystals, thereby facilitating the interfacial Na+ dynamics at low temperature. Furthermore, it effectively blocks the unfavorable side reactions between active materials and electrolytes, improving the structural stability. Consequently, Na0.7Li0.03Mg0.03Ni0.27Mn0.6Ti0.07O2//Na and hard carbon//Na cells deliver a high capacity retention of 90.8 % after 900 cycles at 1C, a capacity over 310 mAh g−1 under −30 °C, respectively, showing long‐term cycling stability and great rate capability at low temperature.

Monolithic Interphase Enables Fast Kinetics for High-Performance Sodium-Ion Batteries at Subzero Temperature.

In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low-concentration electrolyte, consisting of 0.5M NaPF6 dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature. Such an electrolyte generates a thin, amorphous, and homogeneous cathode/electrolyte interphase at low temperature. The interphase is monolithic and rich in organic components, reducing the limitation of Na+ migration through inorganic crystals, thereby facilitating the interfacial Na+ dynamics at low temperature. Furthermore, it effectively blocks the unfavorable side reactions between active materials and electrolytes, improving the structural stability. Consequently, Na0.7Li0.03Mg0.03Ni0.27Mn0.6Ti0.07O2//Na and hard carbon//Na cells deliver a high capacity retention of 90.8 % after 900 cycles at 1C, a capacity over 310 mAh g-1 under -30 °C, respectively, showing long-term cycling stability and great rate capability at low temperature.

Lamellar Nanoporous Metal/Intermetallic Compound Heterostructure Regulating Dendrite-Free Zinc Electrodeposition for Wide-Temperature Aqueous Zinc-Ion Battery.

Aqueous zinc-ion batteries are attractive post-lithium battery technologies for grid-scale energy storage because of their inherent safety, low cost and high theoretical capacity. However, their practical implementation in wide-temperature surroundings persistently confronts irregular zinc electrodeposits and parasitic side reactions on metal anode, which leads to poor rechargeability, low Coulombic efficiency and short lifespan. Here, this work reports lamellar nanoporous Cu/Al2Cu heterostructure electrode as a promising anode host material to regulate high-efficiency and dendrite-free zinc electrodeposition and stripping for wide-temperatures aqueous zinc-ion batteries. In this unique electrode, the interconnective Cu/Al2Cu heterostructure ligaments not only facilitate fast electron transfer but work as highly zincophilic sites for zinc nucleation and deposition by virtue of local galvanic couples while the interpenetrative lamellar channels serving as mass transport pathways. As a result, it exhibits exceptional zinc plating/stripping behaviors in aqueous hybrid electrolyte of diethylene glycol dimethyl ether and zinc trifluoromethanesulfonate at wide temperatures ranging from 25 to -30°C, with ultralow voltage polarizations at various current densities and ultralong lifespan of >4000 h. The outstanding electrochemical properties enlist full cell of zinc-ion batteries constructed with nanoporous Cu/Al2Cu and ZnxV2O5/C to maintain high capacity and excellent stability for >5000 cycles at 25 and -30°C.

Organic Solvent-Based Li–Air Batteries with Cotton and Charcoal Cathode

We report on the construction and investigation of Li–air batteries consisting of a charcoal cathode and cotton texture soaked with different organic solvents containing a lithium triflate (LiOTf) electrolyte. Charcoal was found to be an appropriate cathode for Li–air batteries. Furthermore, cycling tests showed stable operation at over 800 cycles when dimethyl sulfoxide (DMSO) and diethylene glycol dimethyl ether (DEGME) were used as solvents, whereas low electrochemical stability was observed when propylene carbonate was used. The charging, discharging, and long-term discharging steps were mathematically modeled. Electrochemical impedance spectroscopy showed Gerischer impedance, suggesting intensive oxygen transport at the surface of the charcoal cathode. Diffusion, charge transfer, and solid electrolyte interphase processes were identified using distribution of relaxation time analysis. In the polypropylene (PP) membrane soaked with LiOTf in DEGME, three different states of Li ions were identified by 7Li-triple-quantum time proportional phase increment nuclear magnetic resonance measurements. On the basis of the latter results, a mechanism was suggested for Li-ion transport inside the PP membrane. The activity of the charcoal cathode was confirmed by Raman and cyclic voltammetry measurements.

Electrolyte optimization for sodium-sulfur batteries

Due to high theoretical capacity, low cost, and high energy density, sodium-sulfur (Na-S) batteries are attractive for next-generation grid-level storage systems. However, the polysulfide shuttle leads to a rapid capacity loss in sodium-sulfur batteries with elemental sulfur as the cathode material. Most previous studies have focused on nanoengineering methods for creating stable Na anodes and S cathodes. A proven strategy to mitigate the shuttle effect is to covalently bond elemental sulfur to a polymeric backbone and use it as the active ingredient instead of elemental sulfur. In this regard, we synthesized sulfurized polyacrylonitrile (SPAN) cathodes. In addition to the electrodes, electrolyte selection is crucial for sodium sulfur batteries with long cycle life, high energy densities, and rate capabilities. Thus, we explored various electrolyte compositions; specifically organic solvents such as propylene carbonate (PC), dioxolane (DOL), dimethoxyethane, and diglyme (DIG) were mixed in different proportions to create electrolyte solvents with both ethers and carbonates to promote the formation of bilateral solid electrolyte interphase (SEI). This bilateral SEI strategy has been employed to prevent polysulfide shuttle and dendrite growth in lithium-sulfur batteries. Sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) was chosen as the electrolyte salt. The prepared coin cells were tested for rate capability and capacity retention, and the results have been analyzed. High initial discharge capacity of ∼740 mAh g−1 with ∼66% capacity retention over 100 cycles was observed for 0.8M NaTFSI in PC50DOL50 (v/v). The cell with 0.8M NaTFSI in PC50DIG50 has exhibited strong capacity retention of 74.60% with excellent Coulombic efficiency of 99%. Molecular dynamics (MD) simulations were carried out to further understand these results.

Structural study of two polymer chains of poly(2-methoxyethyl glycidyl ether)-b-poly(2-ethoxyethyl glycidyl ether) thermoresponsive block copolymers using molecular dynamics simulations

Block copolymers are expected to be applied in a wide variety of fields due to the property of self-assembly. Our group has reported that poly(glycidyl ether) block copolymers exhibited complex temperature response in aqueous solution. In this study, we investigated the two chains of the block copolymer structure and configurations at different temperatures by using MD simulation. The results showed that at low temperatures, the polymer structure is linear and can form micelles, but above a certain temperature, the polymer structure changes to a U-shape and the micelle structure would be destroyed, which is responsible for the complex temperature response.

Diglyme as a Promoter for the Electrochemical Formation of Quaternary Graphite Intercalation Compounds Containing two Different Types of Solvents

AbstractCo‐intercalation using ether‐based electrolytes renders graphite as a promising anode material in sodium‐ion batteries (SIBs). While most research on electrochemical solvent co‐intercalation in graphite has focused on linear ethers such as mono‐, di‐, tri‐, tetra‐, and penta‐glyme, we herein investigate the possibility of reversible electrochemical co‐intercalation with alternative solvents, especially cyclic ethers tetrahydrofuran (THF) and 1,3‐dioxolane (DOL), which show no signs of co‐intercalation on their own. We demonstrate, however, that this reaction becomes feasible when incorporating diethylene glycol dimethyl ether (2G, diglyme) as an additive. Operando X‐ray diffraction and ex‐situ ss‐NMR techniques are employed comprehensively to understand the co‐intercalation reaction of these cyclic ethers, along with Na+‐glymes, into graphite during cycling. When using these mixed electrolytes i. e., THF/2G and DOL/2G, the voltage profiles changes compared to the pure glyme‐based electrolyte, while showing comparable specific capacities and good long‐term durability. Overall, we propose that even trace amounts of diglyme prompt the co‐intercalation of THF and DOL into graphite layers. This leads to the formation of quaternary graphite intercalation compounds (q‐GICs), expanding beyond the realm of ternary graphite intercalation compounds (t‐GICs).

Thermal properties of glycinin in crowded environments

Crowded environments, commonly found in the food system, are utilized to enhance the properties of soybean proteins. Despite their widespread application, little information exists regarding the impact of crowded environments on the denaturation behaviors of soybean proteins. In this study, we investigated how crowding agents with varying molecular weights, functional groups, and topology affect the denaturation behavior of glycinin under crowded conditions. The results reveal that thermal stability in PEG crowded environments is mainly influenced by both preferential hydration and binding. The stabilization is primarily enthalpy-driven, with aggregation contributing additional entropic stabilization. Specifically, ethylene glycol and diethylene glycol exhibit temperature-dependent, bilateral effects on glycinin stability. At the denaturation temperature, hydrophobic interactions play a predominant role, decreasing glycinin's thermal stability. However, at a molecular weight of 200 g/mol, there is a delicate balance between destabilizing and stabilizing effects, leading to no significant change in thermal stability. With the addition of PEG 400, 1000, and 2000, besides preferential hydration, additional hard-core repulsions between glycinin molecules enhance thermal stability. Methylation modification experiments demonstrated that 2-methoxyethyl ether exerted a more pronounced denaturing effect. Additionally, the cyclization of PEG 1000 decreased its stabilizing effect.