Density Functional Molecular Dynamics Simulations Research Articles

Molecular insights into the CO2 absorption mechanism by superbase protic ionic liquids by a combined density functional theory and molecular dynamics approach

Protic ionic liquids (PILs) are emerging as a new class of sustainable and efficient solvents for CO2 capture, requiring a fundamental understanding of their properties for their optimal design. To obtain a molecular-level understanding of the mechanism behind CO2 absorption in this class of absorbents, we selected four novel and high-efficient PILs prepared from superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo[4.3.0]-5-nonene (DBN) as cations, with imidazole (Im) and pyrazole (Pyr) as anions. Density functional theory (DFT) and molecular dynamics (MD) simulations were used to quantify their interactions and reaction mechanisms as well as the dynamics of the CO2 absorption process. Results indicate that CO2 primarily interacts with the anions of PILs through van der Waals forces, while the cations and anions of PILs mainly engage in strong hydrogen-bonding interactions. Additionally, the anions primarily serve as the absorption reaction sites for CO2, with their molecule centers of mass being the closest. Meanwhile, reaction with CO2 requires overcoming a relatively low energy barrier (i.e., ∼35–40 kJ·mol−1), making them more favorable for regeneration than benchmark solvents. Notably, MD simulations have also shown that CO2 molecules are preferentially accumulating at the gas/PILs interfaces and that chemisorption is leading the CO2 capture at low pressures in these PILs. Among the studied systems [DBUH][Pyr] is the most reacting system with CO2, while [DBUH][Pyr] shows the lower regeneration energy. The findings would shed more light on understanding and designing PILs for CO2 capture.

Integrating experimental and theoretical studies in the development of a novel alginate-based bio-composite for copper anticorrosion in 3.5 % NaCl environments

The development of new coatings based on a biopolymer, epichlorohydrin-modified alginate, and alginate-epichlorohydrin-SrTiO3 nanocomposites incorporating SrTiO3 (STO) nanoparticles in the alginate (Alg) matrix (Alg-Ep-STO), has been addressed in this study. Various characterization techniques were employed to analyze the prepared compounds, including X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), as well as surface analysis methods such as Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). Furthermore, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP) methods were used to evaluate corrosion inhibition and protection durability. The results demonstrate that the incorporation of STO nanoparticles into the alginate matrix with epichlorohydrin significantly improved the metal's resistance to corrosion. The experimental findings received reinforcement from various computational methods, including density functional theory (DFT), Molecular Dynamics (MD) and Monte Carlo (MC) simulations, which were employed to investigate the interactions between the Alg-Ep-STO nanocomposite and the copper surface. The computational outcomes revealed that the Alg-Ep-STO nanocomposite exhibits robust adhesion to the copper surface, maintaining a flat orientation, with its alignment being notably influenced by the presence of STO nanoparticles.

Study on inherent characteristics of asphalt regenerating agents: Insights from density functional theory calculations and molecular dynamics simulations

The asphalt mixtures containing reclaimed asphalt pavement (RAP) are gradually used in pavement. When the RAP content exceeds 25%, the influence of RAP properties on the performance of the asphalt mixture becomes more pronounced. To address this barrier, the incorporation of regenerating agents is adopted to soften RAP asphalt and ensure the performance of the asphalt mixture. Currently, research on the effect of regenerating agents is rapidly advancing, but there remains limited exploration of their inherent characteristics. This study employs advanced tools such as molecular dynamics (MD) simulations and density functional theory (DFT) to investigate the chemical properties and material attributes of regenerating agents. Fourteen common regenerating agents are selected, which can be classified into eight categories (A∼H) based on their structural features. The results reveal that linear alkanes and cycloalkanes are nonpolar surfaces due to their inherent structural characteristics, resulting in larger fraction free volume (FFV) values within the molecular structure. Considering the molecular weight and intermolecular interactions, these components exhibit a higher diffusion coefficient (D) value. In contrast, aromatics with benzene rings experience enhanced polarity and intermolecular interaction due to conjugated electron pairs forming π-π interactions, leading to reduced FFV values and D values. Moreover, the increase in molecular weight of aromatics significantly reduces both intermolecular interactions and D values. The carboxyl group in fatty acids leads to higher polarity, resulting in stronger intermolecular interactions and lower FFV values and D values. However, after esterification, the properties of fatty acid esters show improvement. Glycerol, with its hydroxyl group having the strongest polarity, exhibits a dense arrangement with the highest density and solubility parameters, which may exceed that of asphalt and may not be suitable as a rejuvenator. The investigation reveals that the polarity of regenerating agents is positively correlated with density, cohesive energy density, and solubility parameters.

Boosting Phosphoric Acid Retention in Polymer Electrolyte Membranes by Zwitterions: Insights from DFT Calculations and MD Simulations.

Effective retention of phosphoric acid (PA) is crucial for the efficient operation of fuel cells based on PA-doped polymeric membranes, which is highly challenging due to the moisture-induced loss of PA. Therefore, a comprehensive understanding of the interplay among PA, functional groups, and water is essential for designing membrane materials. Using density functional theory (DFT) calculations and molecular dynamics (MD) simulations, we unveil the remarkable capability of zwitterions to effectively sequester PA, thereby unlocking the potential for fuel cell optimization. Our DFT calculations show that zwitterions, termed "charged proton-accepting bases", exhibit stronger interactions with PA compared to the traditional neutral proton-accepting bases. Furthermore, the presence of water amplifies such a discrepancy, with the zwitterion-PA interactions playing a dominant role in the zwitterion-PA-water cluster due to the strongest affinity of zwitterions to PA. Conversely, the ability of neutral bases to retain PA is significantly attenuated by moisture as the interactions between water and PA surpass those between neutral bases and PA. The strong zwitterion-PA associations arise primarily from the formation of multiple hydrogen bonds. Furthermore, MD simulations reveal the uniform distribution of zwitterions in aqueous environments and their pronounced affinities for both PA and water. In contrast, neutral bases tend to aggregate, interacting limitedly with PA. These findings underscore the effectiveness of zwitterions in boosting PA retention in fuel cells.

Comprehensive investigation of sustainable corrosion inhibitors on Cu–Zn alloy in simulated cooling water: Electrochemical explorations, SEM/EDX analysis, and DFT/molecular simulations utilizing expired Bepotastine-B as a green inhibitor

In terms of green chemistry, the use of the use of expired drugs has recently gained attention as sustainable corrosion inhibitors due to their biodegradability, environmental friendliness, low cost, and easy availability. This paper aimed to evaluate the protective action of expired Bepotastine-B on Cu–Zn alloy in simulated cooling water (SCW) using weight loss (WL), Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), surface morphology analysis and computer modeling methods, including density functional theory (DFT) and molecular dynamic simulations (MS).The variables concentration, reaction temperature, and pH of an expired drug were examined. The electrochemical results demonstrated that the expired Bepotastine-B is a mixed-type inhibitor that blocks both the anodic and cathodic potentials, which exhibited high inhibition. The corrosion rate falls as the Bepotastine increases and increases as the temperature rises. The drug's adsorption on Cu–Zn alloy follows the Langmuir isotherm model. The examination of surface morphology (SEM/EDX) indicated a formation of an insoluble complex and a fine film of inhibitor, which effectively hinders Cu–Zn alloys from deteriorating, covering the surface. These findings confirmed the formation of an adsorbed layer by the Bepotastine-B molecules hindered the dissolving of Cu–Zn alloys. The inhibitory impact of Bepotastine-B, which investigated, theoretically using DFT and the computational results align well with the results obtained from experimental inhibition efficiencies. The inhibition efficiency (IE) improved with raising Bepotastine-B concentration. The maximum IE of 94.6% has been achieved at 300 mg/L. The combination of experimental and computational approaches enhanced our understanding of the corrosion inhibition mechanism and underscored the potential of Bepotastine-B as a sustainable, and effective corrosion inhibitor for Cu–Zn alloy in this medium at dissimilar temperatures. These findings can serve as a useful guideline for future research aimed at investigating the inhibitory impact of expired drugs as a green one.

Harnessing the High Interfacial Electric Fields on Water Microdroplets to Accelerate Menshutkin Reactions.

Even though it is still an emerging field, the application of a high external electric field (EEF) as a green and efficient catalyst in synthetic chemistry has recently received significant attention for the ability to deliver remarkable control of reaction selectivity and acceleration of reaction rates. Here, we extend the application of the EEF to Menshutkin reactions by taking advantage of the spontaneous high electric field at the air-water interfaces of sprayed water microdroplets. Experimentally, a series of Menshutkin reactions were accelerated by 7 orders of magnitude. Theoretically, both density functional theory calculations and ab initio molecular dynamics simulations predict that the reaction barrier decreases significantly in the presence of oriented external electric fields, thereby supporting the notion that the electric fields in the water droplets are responsible for the catalysis. In addition, the ordered solvent and reactant molecules oriented by the electric field alleviate the steric effect of solvents and increase the successful collision rates, thus facilitating faster nucleophilic attack. The success of Menshutkin reactions in this study showcases the great potential of microdroplet chemistry for green synthesis.

Investigation of the mechanisms and adsorption of a new pyrazole derivative against corrosion of carbon steel in hydrochloric acid solution: Experimental methods and theoretical calculations

In an electrolyte of hydrochloric acid (1 M HCl) at 303 K, the effectiveness of the pyrazole derivative N,N,N′,N′-tetrakis((3,5-dimethyl-1 H-pyrazol-1-yl)methyl)pyridine-2,6-diamine (PRPD) as a corrosion inhibitor was examined. Several experimental methods, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface morphology analysis (SEM) coupled with energy dispersive X-ray analysis (EDX), AFM, contact angle (CA), FTIR, X-ray photoelectron spectroscopy (XPS), UV–visible, and X-ray diffraction (XRD), were used to conduct the measurements. To support these experimental findings, we use theoretical calculations such as density functional theory (DFT) and molecular dynamics (MD) simulations. The achieved findings manifested that the PRPD behaves as a powerful corrosion inhibitor, achieving an anti-corrosion performance of 97.2% at 0.001 M. The PDP technique suggests that PRPD is part of a mixed-type inhibitor. The PRPD molecules are chemisorbed at the carbon steel (CS) surface in accordance with the Langmuir isotherm model. On the ground of surface analysis, the build-up of an adsorptive layer inhibitor on the steel surface has been verified. DFT and MD simulation analyses have validated the experimental findings. These results contribute to the creation of successful corrosion control methods by providing insightful information about the inhibition of carbon steel corrosion in a 1 M HCl environment.

Comprehensive Study of Lithium Diffusion in Si/C-Layer and Si/C3N4 Composites in a Faceted Crystalline Silicon Anode for Fast-Charging Lithium-Ion Batteries.

By using silicon (Si) as an anode of lithium-ion batteries, the capacity can be significantly increased, but relatively large volume expansion limits the application as an efficient anode material. Huge volume expansion of the silicon anode during lithiation, however, leads to cracking and losing its connection with the current collector. This shortcoming can be improved by the deposition of a nanometric carbon- or nitrogen-doped carbon coating on the silicon surface, resulting in Si/C-layer and Si/C3N4 interfaces. In this work, Li+ diffusion in Si/C-layer and Si/C3N4 composite materials along three Si surfaces and various ion pathways were carefully analyzed by using density functional theory and ab initio molecular dynamic (AIMD) simulations. Both Si/C and Si/C3N4 interfaces and three Si surfaces of (100), (110), and (111) were investigated. The formation of nitrogen holes and monatomic carbon binders in the composite increases ion diffusivity and limits volume expansion. Furthermore, the Bader analysis shows that the type and orientation of the surfaces have important effects on ion distribution. The results indicated that the C3N4 composite increases Li+ diffusion in Si (100) from 7.82 × 10-5 to 3.17 × 10-4 cm2/s. The presented results provide a guide for the appropriate design of stable and safe high-energy-density batteries.

Experimental, surface and theoretical investigations of a new benzodiazepine derivative designed for corrosion inhibition of carbon steel in 15% hydrochloric acid medium under hydrodynamic environment

The prime objective of the present research is to explore the green synthesis of benzodiazepine derivative (BDZ) using the microwave irradiation method and its application as a novel corrosion inhibitor for carbon steel in 15 % HCl under hydrodynamic condition at 1500 rpm. The performance ability of BDZ rises from 42.35 % (without BDZ) to 93.41 % (with BDZ). The BDZ depicted the cathodic inhibitive nature. The charge transfer resistance (Rct) changes from 41.9 Ω cm−1 to 313 Ω cm−1 with the falling of double layer capacitance (Cdl) from 92.1 μF cm−2 to 45.2 μF cm−2 on the introduction of BDZ supports the adsorption of BDZ molecules at the active sites of the carbon steel surface. The molecular adsorption of BDZ is governed by Temkin isotherm. The results of the surface analysis support the creation of an inhibitive layer of BDZ over the carbon steel surface. Density Functional Theory (DFT) and Molecular Dynamic simulations (MD) calculations were further performed to justify the experimental results. Molecular docking was used to analyze the BDZ and sulfate-reducing bacteria (SRB) protein interaction.

Repurposing of Strychnine as the Potential Inhibitors of Aldo-keto Reductase Family 1 Members B1 and B10: Computational Modeling and Pharmacokinetic Analysis.

AKR1B1 and AKR1B10 are important members of aldo-keto reductase family which plays a significant role in cancer progression by modulating cellular metabolism. These enzymes are involved in various metabolic processes, including the synthesis and metabolism of hormones, detoxification of reactive aldehydes, and the reduction of various endogenous and exogenous compounds. This study aimed to explore the potential of strychnine as an anticancer agent by targeting AKR1B1 and AKR1B10 via drug repurposing approach. To assess the drug-like properties of strychnine, a physiologically based pharmacokinetic (PKPB) model and High Throughput Pharmacokinetics (HTPK) approach were employed. The obtained results fell within the expected range for drug molecules, confirming its suitability for further investigation. Additionally, density functional theory (DFT) studies were conducted to gain insight into the electronic properties contributing to the drug molecule's reactivity. Building upon the promising DFT results, molecular docking analysis using the AutoDock tool was performed to examine the binding interactions between strychnine and the proposed targets, AKR1B1 and AKR1B10. Findings from the molecular docking studies suggested a higher probability of strychnine acting as an inhibitor of AKR1B1 and AKR1B10 with docking scores of - 30.84 and - 29.36kJ/mol respectively. To validate the stability of the protein-ligand complex, Molecular Dynamic Simulation (MDS) studies were conducted, revealing the formation of a stable complex between the enzymes and strychnine. This comprehensive approach sheds light on the potential effectiveness of strychnine as a treatment for breast, lung, liver, and pancreatic cancers, as well as related malignancies. The novel insights gained from the physiologically based pharmacokinetic modeling, density functional theory, molecular docking, and molecular dynamics simulations collectively support the prospect of strychnine as a promising molecule for anticancer therapy. Further investigations are warranted to validate these findings and explore the therapeutic potential of strychnine in preclinical and clinical settings.

Experimental and theoretical study on corrosion inhibition and adsorption performance of Ipomoea batatas L. leaf extract for mild steel

Recent years have seen a surge in interest in efficient, green, and eco-friendly corrosion inhibitors, leading to extensive research on plant extracts. This study investigates the active phytochemicals in abundant Ipomoea batatas L. leaves, which were extracted with ultrasonics using an ethanol–water solution and applied to mitigate the corrosion of mild steel (MS) in a 1 M HCl pickling solution. The chemical compositions and corrosion inhibition properties of the leaf extract of Ipomoea batatas L. (IBLE) were explored through multiple experiments, and the adsorption thermodynamic and kinetic parameters were analysed. Electrochemical results indicated that the corrosion inhibition mechanism of IBLE is a geometric coverage effect; IBLE acts as a mixed-corrosion inhibitor; and the inhibition efficiency increases with extract concentration and solution temperature, reaching up to 96.4 % at 318 K. X-ray photoelectron spectroscopy (XPS) results showed the adsorption of C=C, C–N, C–N+, C=N, C=N+, C=O, C=O+, C–O, C–O+, Fe-N and other carbonaceous groups on the steel surface. Surface observation confirmed that IBLE can effectively retard steel corrosion. The adsorption analysis revealed that the protective film is a monolayer that follows the Langmuir isotherm, and the oriented adsorption of active ingredients enhances the order of the MS surface. Density functional theory (DFT) and molecular dynamics (MD) simulations were conducted to examine the relationship between inhibition and adsorption of IBLE. The theoretical calculations confirmed that the active compounds in IBLE can adsorb on the Fe (110) surface through physical patterns and by sharing charges with iron to form coordinate bonds. The adsorption abilities of different ingredients vary, but all exhibit synergistic adsorption effects. IBLE can be considered an efficient and renewable corrosion inhibitor for MS in HCl pickling media.

Examination of the main chemical components of essential oil of Syzygium aromaticum as a corrosion inhibitor on the mild steel in 0.5 M HCl medium

The study delves into the versatile applications of essential oils, natural aromatic compounds derived from plants through hydro-distillation or cold extraction, across industries such as cosmetics, fragrances, food processing, traditional medicine, and agriculture. Notably, these plant-derived compounds have gained prominence as corrosion inhibitors for metals and alloys in acidic environments. The research focuses on evaluating the inhibitory capacity of Suzygium aromaticuim on regular steel submerged in an acidic medium, employing various concentrations of essential oil (1.5 g/L to 6 g/L). The inhibitory effectiveness was evaluated using electrochemical techniques, including potentiodynamic polarization curves and electrochemical impedance spectroscopy. Electrochemical measurements and optical microscope analyses were used to examine the effect of cloves' essential oils on the corrosion resistance of mild steel in a 0.5 M HCl media. NMR and IR spectroscopy were used to learn about the two isolated chemicals (eugenol and β-caryophyllene). The corrosion-inhibiting properties of β-caryophyllene at 2 g/L in an acidic media were studied. Density functional theory (DFT) computations and molecular dynamics simulations were used to isolate the essential oil component of cloves responsible for the corrosion inhibition of mild steel. Inhibition effectiveness peaked at 94 % at 4 g/L, leading the researchers to infer that the natural substance is a mixed-type inhibitor. Optical microscope analysis confirmed the protection offered at the optimum concentration, while β-caryophyllene demonstrated noteworthy inhibitor efficiency, especially when compared to Eugenol. DFT analysis further supported the corrosion inhibition potential of β-caryophyllene in aggressive solutions.

Comparative study of cationic Nile blue and anionic methyl orange dyes adsorption in water on the (110) surface of metal chlorides by DFT and MD approaches

Computational studies using density functional theory (DFT) and molecular dynamics simulations (MD) provide a valuable way to evaluate the removal of dyes by different adsorbents. In this study, Nile blue (with a positive charge; NB+) and methyl orange (with a negative charge; MO−) were used to examine the adsorptive performance of metal chlorides MCl2 (where M = Mg, Mn, Zn or Ni) from water. The calculated gap energies of NB+ and MO− were 5.333 and 2.395 eV, respectively, suggesting that the NB+ molecule is more reactive, electrophilic and can adsorb strongly on the MCl2 surface compared to MO−. Frontier molecular orbitals, Mulliken charge and an electrostatic potential map were used to explain the redox reactive sites of the investigated molecules. In addition, possible donor–acceptor interactions of molecules were assessed by natural bond orbital analysis. The negative values of back-donation energy ΔEback-donation for both dyes reflected that back donation for both dyes was energetically favorable. Furthermore, the most stable energy configuration of NB+ and MO− adsorption on MCl2 was determined by MD simulations. These simulations showed that both dyes can be adsorbed onto the MCl2 (110) surface in a nearby horizontal position. The radial distribution function peak values for all systems occurred at distances greater than 3.5 Å, indicating that the dyes were physically adsorbed onto the MCl2 surfaces through van der Waals interactions. The negative values of adsorption energy for both studied dyes indicated spontaneity of the adsorption process. Furthermore, MD simulations revealed that the adsorption energies between NB+ and MCl2 were much higher than between MO− and MCl2.

Theoretical investigations on CL-20/ANTA co-crystal explosive via molecular dynamics method.

The study of CL-20 co-crystal has always been a focal point within the field of energetic material modification. In this study, we employed a combination of density functional theory and molecular dynamics simulations to investigate the properties of hexanitrohexaazaisowurtzitane (CL-20)/3-amino-5-nitro-1,2,4-triazole (ANTA) with different molar ratios ranging from 4:1 to 1:4. Additionally, EXPLO-5 software utilized to predict the detonation properties and products of pure CL-20, ANTA, and CL-20/ANTA systems. The results revealed that there was an interaction between CL-20 and ANTA molecules, which had the potential to form a co-crystal. The most likely molar ratio for co-crystal formation was 1:1, and the main driving forces for co-crystal formation were electrostatic force, dispersion force, and van der Waals force. The co-crystal explosive exhibited moderate sensitivity and excellent mechanical properties. Furthermore, the co-crystal detonation performance at a molar ratio of 1:1 was between that of CL-20 and ANTA, representing a new type of insensitive high-energy material. The properties of CL-20/ANTA co-crystal were predicted by molecular dynamics (MD) method under Materials Studio software. For the whole MD simulations, set the temperature at 298 K, and the pressure was 0.0001 GPa. Conducted MD simulation under the NPT ensemble for a total simulation duration of 1 ns. The first 0.5 ns was used for thermodynamic equilibrium, and the last 0.5 ns was used for statistical calculation and analysis. Sampling was recorded every 10 fs during the calculation.

Computational investigation of the structures, properties, and host‐guest chemistry of prism[n]arenes

AbstractThe discovery of new and functional macrocyclic host compounds is an important part of supramolecular chemistry. Since the experimental synthesis, prism[n]arenes (Pr[n]As), a class of naphthol‐based macrocyclic arenes, have attracted much attention. In this work, from the perspective of theoretical calculation and research, Pr[n]As (n = 4 ~ 7) were studied by density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The prismatic configuration isomers, electronic structures, absorption spectra, and host‐guest chemistry were discussed thoroughly. DFT calculation results showed that 1,5‐, 3,7‐, and “hybrid” 15,37‐Pr[n]As were the most representative configurations with the rigid prismatic molecular skeleton. Based on time‐dependent density functional theory (TD‐DFT), the absorption spectra of Pr[n]As were all in the range of ultraviolet light which were mainly attributed to π‐π* transitions. The molecular cavities of Pr[n]As were electron‐rich and capable of accommodating a variety of cations or electron‐conjugated molecules. MD simulation results showed that a Pr[n]A molecule was able to capture the guest molecule into its molecular cavity and maintain in the state of equilibrium in solvents.

Role of copper as current collectors in the reductive reactivity of polymers for anode-free lithium metal batteries - Insights from DFT and AIMD studies

Understanding the role of current collectors (CCs) in the reductive reactivity of polymers on Li metal and the resultant solid electrolyte interphase (SEI) formation is essential for improving the performance of anode-free lithium metal batteries (AFLMBs). In this study, we have examined the reactivity of three polymeric hosts: poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(trimethylene carbonate) (PTMC) at Li metal supported on Cu surfaces (Li/Cu) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. In particular, the effect of copper (Cu) CCs on polymer stability, electronic structure, and their reduction reactions is investigated and compared to that of pure Li (100) surface. Through time-dependent Bader charge transfer analysis, electron transfer is identified as the triggering factor for polymer reduction. Based on the simulations, we find that the Cu CCs have a significant influence on the charge distribution of the Li metals, which increases electron transfer to the polymers and thereby accelerates polymers reduction. This thereby leads to different reaction mechanisms as compared to on Li-metal. The findings suggest that utilization of Cu CCs avoids the production of CO molecules and improves the quality of the formed SEI layer.

A Theoretical Study on the Underlying Factors of the Difference in Performance of Organic Solar Cells Based on ITIC and Its Isomers.

Recently, non-fullerene-based organic solar cells (OSCs) have made great breakthroughs, and small structural differences can have dramatic impacts on the power conversion efficiency (PCE). We take ITIC and its isomers as examples to study their effects on the performance of OSCs. ITIC and NFBDT only differed in the side chain position, and they were used as models with the same donor molecule, PBDB-T, to investigate the main reasons for the difference in their performance in terms of theoretical methods. In this work, a detailed comparative analysis of the electronic structure, absorption spectra, open circuit voltage and interfacial parameters of the ITIC and NFBDT systems was performed mainly by combining the density functional theory/time-dependent density functional theory and molecular dynamics simulations. The results showed that the lowest excited state of the ITIC molecule possessed a larger ∆q and more hybrid FE/CT states, and PBDB-T/ITIC had more charge separation paths as well as a larger kCS and smaller kCR. The reason for the performance difference between PBDB-T/ITIC and PBDB-T/NFBDT was elucidated, suggesting that ITIC is a superior acceptor based on a slight modulation of the side chain and providing a guiding direction for the design of superior-performing small molecule acceptor materials.

Electron Density Learning of Z-Bonds in Ionic Liquids and Its Application.

Ionic liquids (ILs) exhibit fascinating properties due to special Z-bonds and have been widely used in electrochemical systems. The local Z-bond networks potentially cause a discrepancy in electrochemical properties. Understanding the correlations between the Z-bond energy (EZ-bond) and the electrochemical properties is helpful to identify appropriate ILs. It is difficult to estimate the correlations from single density functional theory calculations or molecular dynamic simulations. In this work, a machine learning model targeting the electronic density (ρBCP) of Z-bonds has been trained successfully, as expected for use in systems above the nanoscale size. The connection between the EZ-bond and the electrochemical potential window in ILs@TiO2, as well as that between the EZ-bond and the charge carrier mobility in ILs-PEDOT:Tos@SiO2, was separately investigated. This study highlights an efficient model for predicting ρBCP in nanoscale systems and anticipates exploring the connection between Z-bonds and the electrochemical properties of IL-based systems.

Synergetic Inhibition and Corrosion-Diagnosing Nanofiber Networks for Self-Healing Protective Coatings.

Organic coatings lack durability in marine corrosive environments. Herein, we designed a self-healing coating with a novel nanofiber network filler for enhanced protection. Using electrospinning, we created a core-shell structure nanofiber network consisting of polyvinyl butyral (PVB) as the shell material and gallic acid (GA) and phenanthroline (Phen) as the core material. The PVB@GA-Phen nanofiber network, which includes synergistic corrosion inhibitors (GA-Phen), was embedded in an epoxy coating (PVB@GA-Phen/epoxy) and applied to carbon steel. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations demonstrated that the GA-Phen combination, through hydrogen bond interaction, facilitated inhibitor adsorption on the steel surface. The GA-Phen combination diagnosed corrosion and formed a protective film on the scratched areas. The sustained release of Phen-GA combination inhibitors for up to 240 h resulted in an 88.63% healing efficiency of the PVB@GA-Phen/epoxy (PGP/EP) coating. The long-term corrosion resistance tests confirmed the effective barrier performance of the PGP/EP coating in 3.5 wt % NaCl solution. Moreover, the incorporation of the nanofiber network in the epoxy coating provided passive barrier, corrosion-diagnosing, and anticorrosion properties for carbon steel protection. The designed coating has the potential to continuously monitor the coating/metal system and could serve as a foundation for developing new anticorrosion coatings.

Vacancy mediated fast sodium-conduction in halide sodalites: A theoretical study

All-solid-state sodium-ion batteries (ASSSIBs) are viewed as a potential alternative to Li-ion batteries due to the advantages in safety and cost. Na-ion electrolytes are the key component of ASSSIBs and required to possess low electronic conductivity, high ionic conductivity, wide electrochemical stable window, and good electrode compatibility. Framework structures, like Na8(AlSiO4)6X2 (X = Cl, Br and I), receive broad research interest for catalysis, ion exchange and adsorption due to the interesting open structure. However, little attention is paid to such types of minerals for superionic conductors. In this investigation, a first-principles study using density functional theory and ab initio molecular dynamic simulations are carried out to predict electronic structure, thermodynamic interface stability and Na-ionic conductivity of Na8(AlSiO4)6X2, suggesting wide bandgaps (>6 eV) but extremely low ionic conductivity in perfect Na8(AlSiO4)6X2. By introducing artificial Na vacancy, three-dimensional diffusional pathway forms in the structure and generates significantly improved sodium conduction while maintaining the energetic and thermal stability, demonstrating the potential for ASSSIBs.