Effect Of Electrical Double Layer Research Articles

Does the Electrical Double Layer Contribute to the Mechanism of Action of Antimicrobial Peptides?

AbstractThis concept paper elucidates the possible influence of the electrical double layer (EDL) and the polyelectrolytic nature of bacterial cell walls on the behavior of antimicrobial peptides (AMPs) and lipopeptides. It proposes that the presence of EDL adjacent to lipid membranes may play a crucial role in inducing peptide aggregation and conformational changes, thus affecting their antimicrobial activity. Furthermore, it emphasizes that the negatively charged components in both Gram‐positive and Gram‐negative bacterial cell walls may act as polyelectrolytes, effectively reducing the critical micellization concentration (CMC) of positively charged peptides and lipopeptides. This reduction is expected to facilitate their aggregation, potentially enhancing their accumulation at the bacterial membrane and increasing their effectiveness in disrupting membrane integrity and exerting antimicrobial activity. Therefore, understanding the interplay between EDL effects, polyelectrolytic properties of bacterial cell walls, and the behavior of antimicrobial peptides is essential for elucidating their mechanisms of action and optimizing their therapeutic potential.

Built-in Electric Fields in Heterostructured Lamellar Membranes Enable Highly Efficient Rejection of Charged Mass.

Separation membranes with homogeneous charge channels are the mainstream to reject charged mass by forming electrical double layer (EDL). However, the EDL often compresses effective solvent transport space and weakens channel-ion interaction. Here, built-in electric fields (BIEFs) are constructed in lamellar membranes by assembling the heterostructured nanosheets, which contain alternate positively-charged nanodomains and negatively-charged nanodomains. We demonstrate that the BIEFs are perpendicular to horizontal channel and the direction switches alternately, significantly weakening the EDL effect and forces ions to repeatedly collide with channel walls. Thus, highly efficient rejection for charged mass (salts, dyes, and organic acids/bases) and ultrafast water transport are achieved. Moreover, for desalination on four-stage filtration option, salt rejection reaches 99.9% and water permeance reaches 19.2 L m-2 h-1 bar-1. Such mass transport behavior is quite different from that in homogeneous charge channels. Furthermore, the ion transport behavior in nanochannels is elucidated by validating horizontal projectile motion model.

Built‐in Electric Fields in Heterostructured Lamellar Membranes Enable Highly Efficient Rejection of Charged Mass

Separation membranes with homogeneous charge channels are the mainstream to reject charged mass by forming electrical double layer (EDL). However, the EDL often compresses effective solvent transport space and weakens channel‐ion interaction. Here, built‐in electric fields (BIEFs) are constructed in lamellar membranes by assembling the heterostructured nanosheets, which contain alternate positively‐charged nanodomains and negatively‐charged nanodomains. We demonstrate that the BIEFs are perpendicular to horizontal channel and the direction switches alternately, significantly weakening the EDL effect and forces ions to repeatedly collide with channel walls. Thus, highly efficient rejection for charged mass (salts, dyes, and organic acids/bases) and ultrafast water transport are achieved. Moreover, for desalination on four‐stage filtration option, salt rejection reaches 99.9% and water permeance reaches 19.2 L m‐2 h‐1 bar‐1. Such mass transport behavior is quite different from that in homogeneous charge channels. Furthermore, the ion transport behavior in nanochannels is elucidated by validating horizontal projectile motion model.

Achieving Reconfigurable Excitatory–Inhibitory Response in Unipolar Synaptic Memtransistors by the Synergistic Effects of Electric Double Layer and Charge Trapping

Achieving Reconfigurable Excitatory–Inhibitory Response in Unipolar Synaptic Memtransistors by the Synergistic Effects of Electric Double Layer and Charge Trapping

The importance of properly correcting the electric double layer effect in unravelling the intrinsic kinetics of electrode reactions

Understanding the effects of the electric double layer (EDL) on electrode kinetics is of great importance for improving the performance of electrochemical devices. In this work, by using the HER at Au(111) in x M HClO4 ​+ ​(1−x) M NaClO4 or NaOH as a model reaction, the intrinsic kinetic parameters for HER has been unveiled based on the modified Poisson-Nernst-Planck equations and the Frumkin-Butler-Volmer theory. Our analysis reveals that i) the EDL effects induced changes in proton concentration cH+RP and electric potential ϕRP at the reaction plane are the main reason for the difference of HER current in the cases with x M HClO4 and x M HClO4 ​+ ​(1−x) M NaClO4; ii) the EDL effects are the main origin for the difference in HER current between acidic and alkaline solutions at the Au(111). Our work demonstrates that microkinetic simulation with properly considering the EDL effects is important for unravelling intrinsic reaction kinetics of electrocatalytic reactions.

Nanoscale chloride diffusion in alkali-activated steel slag and ultrafine blast furnace slag considering the electrical double layer effect

Utilizations of industrial byproducts and wastes as much as possible, together with desirable durability, are essential to sustainable development of building materials. In this work, the chloride diffusion behavior of alkali-activated steel slag (SS) and ultrafine blast furnace slag (UFS) is studied, towards deeper insights into the effect of electrical double layer on the resistance to chloride penetration. The microstructure improvement of alkali-activated SS with increasing addition of UFS was examined by means of X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, mercury intrusion porosimetry and nitrogen sorption. The zeta potentials above the pore surface of various alkali-activated SS-UFS systems were measured and compared. The electrostatic resistance of the electrical double layer to chloride diffusion was analyzed and discussed. Results indicate that UFS dosages above 40% substantially refines the pore structure of alkali-activated SS and then the mechanism governing chloride penetration shifts from capillary transport to gel transport. The exposure of higher chloride sodium concentration results in the pore surface of alkali-activated SS-UFS systems to be less negatively charged and the zeta potential is reversed to be positive value after continuous ion exchange between sodium and calcium. The presence of UFS can remarkably increase the proportion of physically bound chloride that attains approximately 80% of the total binding capacity. The impediment of electrical double layer to chloride diffusivity becomes increasingly pronounced with pore structure refinement, especially for mixtures with diffusion coefficients below 5 × 10−12 m2/s obtained based on Fick's law of diffusion.

Thermal dynamics assessment for multi-phase flow analysis with motile cilia and electric double layer effects: Application of Levenberg–Marquardt backpropagation NNs

Ciliary movement holds substantial importance in the realm of biomedical research. Disorders arising from impaired ciliary motion, such as primary ciliary dyskinesia and specific respiratory ailments, underscore the critical need to investigate both the normal functioning and dysfunction of cilia. Such research is fundamental to the development of effective treatments and therapies. This work explores the application of Levenberg–Marquardt backpropagation neural networks (LMBP-NNs) for simulating the flow of a non-Newtonian Jeffery fluid in peristaltic motion. Inspired by synchronous ciliary movement, microfluidic systems mimicking cilia functionality have been developed. These artificial cilia can generate controlled fluid flow patterns, enabling various applications such as drug delivery, mixing, and particle sorting in lab-on-a-chip devices. The present study focuses on measuring thermal and mass transfer in beating cilia during multiphase peristaltic pumping of Jeffery fluid in two- and three-dimensional channels using transverse magnetohydrodynamics in a porous medium. The governing equations for the non-Newtonian Jeffery fluid in both the fluid and dusty phases are formulated, and exact solutions are calculated for fluid phase velocity, particulate phase velocity, temperature, concentration, and pressure gradient. The physical behavior is investigated by graphing dimensionless parameters for velocity, temperature, and concentration profiles in both solid and liquid phases. The trapping phenomena is depicted by showing streamlines of various dimensionless characteristics such as porosity velocity and volume percentage. The LMBP-NNs approach is then used to train, test, and verify the neural network models using the reference datasets. The accuracy of the LMBP-NN is assessed using statistical data such as mean square error, curve fitting graphs, regression plots, and error histograms. The study also investigates flow model limits for momentum, temperature, and concentration profiles using visual representations. This study illustrates the computational capability of LMBP-NNs in modeling the peristaltic flow of Jeffery fluid and gives useful insights into fluid flow behavior in microfluidic devices containing artificial cilia. The findings help to better understand and optimize these systems for a variety of fluid manipulation and transportation applications.

Characterizing the Janus colloidal particles in AC electric field and a step towards label-free cargo manipulation

In recent years, researchers have been exploring Janus particles, a unique type of colloidal system, which has gained enormous attention across diverse fields, from soft matter physics to biology. These particles, possessing an asymmetric surface, can be manipulated in the fluid using external energy sources. This versatility makes them suitable for mimicking biological systems and applications like cargo transportation, drug delivery, biosensing, and environmental cleanup. The study focuses on the response of metal-dielectric (Ti-PMMA) Janus spheres in the AC field, created through the Physical Vapor Deposition (PVD) technique. When subjected to a uniform AC electric field, these particles exhibit different dynamic behaviors at various frequency ranges. The particles show diverse responses from induced-charge electrophoresis (ICEP: 500 Hz-80 kHz) to reversed motion (r: ICEP:100 kHz-1 MHz) and linear chain formation (1 MHz). Additionally, they randomly cluster near the lower characteristic frequency (800 Hz) of the ICEP, whereas they exhibit the 3D motion at frequencies (100 Hz) below this lower characteristic value. The mechanisms behind these dynamic phenomena could be explained by considering the concept of electric double layer (EDL), self-dielectrophoresis (sDEP), dipolar interactions, hydrodynamic interactions, and electrothermal effects. These active Janus Colloids are further leveraged to manipulate 1 µm diameter PMMA passive microparticles and E. coli bacteria at 1 kHz, showcasing their potential applications in cargo delivery under various microfluidic research areas. The manipulation of payloads could be explained based on dielectrophoretic trapping due to locally generated field gradients around the surface of the Janus sphere. Therefore, the present work offers an unprecedented opportunity to study such out-of-equilibrium complex active matter systems and create novel functional materials. Moreover, it could also be extended as a fuel-free microrobotics system for various biomedical applications such as sensing and on-demand drug or cargo delivery inside the microfluidics chamber.

Ionic liquid with hydrogen bonding reducing leakage charge for enhancing triboelectric performance

Refining the dielectric layer of a triboelectric nanogenerator (TENG) has been shown to maximize its output performance. Among the available strategies, utilizing an ionic dielectric can improve the output performance notably through the internal formation of an electrical double layer (EDL). However, ions dispersed in the ionic dielectric inevitably cause leakage charge between the surface charged layer and electrode of the ionic dielectric; this reduces the charge density, directly affecting output performance. Here, we investigate optimization of the ionic dielectric of a TENG using various ionic liquids (ILs), with the alkyl chain lengths of the cations and fluoride of anions with different size, to achieve power enhancement based on the EDL effect while concurrently suppressing leakage charge via hydrogen bonding. To elucidate the power enhancement working mechanisms within the ionic dielectric, we characterize the chemical, mechanical, and electrochemical properties of the ionic dielectric, including formation of hydrogen bonds, ionic conductivity, and dielectric constant. These parameters are investigated by varying the ion types, molecular sizes, and concentrations of the ILs within the ionic dielectric. As a results, our findings reveal that an IL of OMIM+PF6- dissolved in a base material of thermoplastic polyurethane (TPU) significantly enhances the voltage and current by 2.3 and 2.9 times, respectively, compared to those of a conventional TENG with TPU. These findings are expected to be implemented across a wide range of TENGs, paving the path for their advanced applications in next-generation energy harvesting.

Potential and electric double-layer effect in electrocatalytic urea synthesis

Electrochemical synthesis is a promising way for sustainable urea production, yet the exact mechanism has not been fully revealed. Herein, we explore the mechanism of electrochemical coupling of nitrite and carbon dioxide on Cu surfaces towards urea synthesis on the basis of a constant-potential method combined with an implicit solvent model. The working electrode potential, which has normally overlooked, is found influential on both the reaction mechanism and activity. The further computational study on the reaction pathways reveals that *CO-NH and *NH-CO-NH as the key intermediates. In addition, through the analysis of turnover frequencies under various potentials, pressures, and temperatures within a microkinetic model, we demonstrate that the activity increases with temperature, and the Cu(100) shows the highest efficiency towards urea synthesis among all three Cu surfaces. The electric double-layer capacitance also plays a key role in urea synthesis. Based on these findings, we propose two essential strategies to promote the efficiency of urea synthesis on Cu electrodes: increasing Cu(100) surface ratio and elevating the reaction temperature.

Effects of joule heating and viscous dissipation on electromagneto-hydrodynamic flow in a microchannel with electroosmotic effect: Enhancement of MEMS cooling

This paper inspects the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a microchannel. Dimensionless formulations of the Poisson-Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profile were obtained using the method of undetermined coefficients. The Debye-Hückel linearization is used to get exact solution for the electric potential. The results showed that Brinkmann number [Formula: see text], Joule heating parameter [Formula: see text], Debye-Hückel parameter [Formula: see text], Hartmann number [Formula: see text], and electric field [Formula: see text] have a substantial impact on flow formation and heat transfer. The complex interaction between joule heating, viscous dissipation, and the EOF effect were accurately captured. The range values for the governing parameter for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] are [Formula: see text], and[Formula: see text] respectively.

Rapid Fabrication of High-Resolution Flexible Electronics via Nanoparticle Self-Assembly and Transfer Printing.

Printed electronic technology serves as a key component in flexible electronics and wearable devices, yet achieving compatibility with both high resolution and high efficiency remains a significant challenge. Here, we propose a rapid fabrication method of high-resolution nanoparticle microelectronics via self-assembly and transfer printing. The tension gradient-electrostatic attraction composite-induced nanoparticle self-assembly strategy is constructed, which can significantly enhance the self-assembly efficiency, stability, and coverage by leveraging the meniscus Marangoni effect and the electric double-layer effect. The close-packed nanoparticle self-assembly layer can be rapidly formed on microstructure surfaces over a large area. Inspired by ink printing, a transfer printing strategy is further proposed to transform the self-assembly layer into conformal micropatterns. Large-area, high-resolution (2 μm), and ultrathin (1 μm) nanoparticle microelectronics can be stably fabricated, yielding a significant improvement over fluid printing methods. The unique deformability, recoverability, and scalability of nanoparticle microelectronics are revealed, providing promising opportunities for various academic and real applications.

FRACTAL STUDY ON THE PERMEABILITY IN CHARGED MICRO-FRACTURED POROUS MEDIA

Fractured porous media is of great significance to the exploration and development of unconventional reservoirs. In this paper, a fractal model for permeability through micro-fractured porous media with consideration of the electric double layer (EDL) effect is proposed based on the fractal theory. The present model indicates that the permeability is a function of the electrokinetic parameters and micro-structural parameters of fractured porous media, and each parameter has a clear physical meaning, the results from the proposed model are found to be in good agreement with experimental data. Moreover, factors influencing the permeability are also analyzed in detail. The results indicate that the more obvious EDL effects will lead to permeability becoming lower. The present fractal model for the permeability with the EDL effect can provide guidance for tight reservoir development or other micro-porous media transportation.

The pH-Induced Increase of the Rate Constant for HER at Au(111) in Acid Revealed by Combining Experiments and Kinetic Simulation.

Origins of pH effects on the kinetics of electrocatalytic reactions involving the transfer of both protons and electrons, including the hydrogen evolution reaction (HER) considered in this study, are heatedly debated. By taking the HER at Au(111) in acid solutions of different pHs and ionic concentrations as the model systems, herein, we report how to derive the intrinsic kinetic parameters of such reactions and their pH dependence through the measurement of j-E curves and the corresponding kinetic simulation based on the Frumkin-Butler-Volmer theory and the modified Poisson-Nernst-Planck equation. Our study reveals the following: (i) the same set of kinetic parameters, such as the standard activation Gibbs free energy, charge transfer coefficient, and Gibbs adsorption energy for Had at Au(111), can simulate well all the j-E curves measured in solutions with different pH and temperatures; (ii) on the reversible hydrogen electrode scale, the intrinsic rate constant increases with the increase of pH, which is in contrast with the decrease of the HER current with the increase of pH; and (iii) the ratio of the rate constants for HER at Au(111) in x M HClO4 + (0.1 - x) M NaClO4 (pH ≤ 3) deduced before properly correcting the electric double layer (EDL) effects to the ones estimated with EDL correction is in the range of ca. 10 to 40, and even in a solution of x M HClO4 + (1 - x) M NaClO4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL correction. The importance of proper correction of the EDL effects as well as several other important factors on unveiling the intrinsic pH-dependent reaction kinetics are discussed to help converge our analysis of pH effects in electrocatalysis.

(Invited) Modeling of the Electric Double Layer (EDL) at Li/SEI/Electrolyte Interfaces

Liquid electrolytes, consisting of salts, solvents, and additives, must form a stable solid electrolyte interphase (SEI) to ensure the performance and durability of lithium(Li)-ion batteries. However, the electric double layer (EDL) structure near charged surfaces is still unsolved, despite its importance in dictating the species being reduced for SEI formation near a negative electrode. Recently, we have developed an interactive Molecular Dynamics -Density Functional Theory -data statistics (MD-DFT-data) model to investigate the reduction reactions of multicomponent electrolytes within the EDL. We will illustrate the effect of EDL on SEI formation in two essential electrolytes, the carbonate-based electrolyte for Li-ion batteries and the ether-based electrolyte for batteries with Li-metal anodes. Our results reveal that the role of fluoroethylene carbonate (FEC) additive differs drastically in the two electrolytes as an SEI modifier to form the beneficial F-containing SEI component (e.g., LiF). The competition among the cations, anions, and various species in the solvents with a charged surface at different temperatures can all jointly determine the EDL structure and therefore the SEI compositions. [1]While the classical Poisson–Boltzmann EDL model developed for fully solvated ions face new challenges in high-concentration liquid electrolytes (HCE), localized high-concentration liquid electrolytes (LHCE) as well as solid electrolytes (SE), new theoretical developments are required. We will introduce a new DEL model in SE and SEI by solving the DFT-informed Poisson–Fermi–Dirac equation and demonstrate how it can be used for interlayer thickness design. [2][1] Wu, Q.S, McDowell, M.T., & Qi, Y., Journal of the American Chemical Society 145 (4), 2473-2484 (2023)[2] Swift, M.W., Swift, J.W. & Qi, Y. Modeling the electrical double layer at solid-state electrochemical interfaces. Nat Comput Sci 1, 212–220 (2021)

Analysis of Joule heating and viscous dissipation on electromagnetohydrodynamic flow with electroosmotic effect in a porous microchannel: A heat transfer miniature enhancement

AbstractThis work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson–Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profiles were obtained using the method of undetermined coefficients. The Debye–Hückel linearization is used to get an exact solution for the electric potential. The results showed that the Brinkmann number , Joule heating parameter , Debye–Hückel parameter , Hartmann number , electric field , and suction/injection parameter have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided to deliver a greater understanding of the influence of relevant parameters on the results achieved.

3D Tea-Residue Microcrystalline Cellulose Aerogel with Aligned Channels for Solar-Driven Interfacial Evaporation Co-generation.

Solar-driven interfacial evaporation co-generation (SIE-CG) technology is of great significance in solving the problem of water and energy shortage. Herein, we report the ionic liquid-assisted alignment of waste biomass tea residue-based microcrystalline cellulose for aerogels (abbreviated as TPPA-5) with aligned channels for solar-driven interfacial evaporation co-generation. In the ionic liquid, strong H-bonding is formed between the pyranoid rings of cellulose combined with the slow freezing technique, resulting in the microcrystalline cellulose being reoriented, which allowed TPPA-5 to form abundant aligned channels after solvent replacement and freeze-drying. These aligned channels enable the brine to form a localized circulating flow, which is conducive to the improvement of the TPPA's evaporation rate and salt resistance. The salinity gradient is naturally formed in the channel of TPPA, which enables TPPA-5 to show excellent power generation performance. The evaporation rate of TPPA-5 can reach 3.39 kg m-2 h-1 under 1 kW m-2. With methanol as a highly polar proton solvent, the maximum output voltage obtained was 67.534 mV due to the overlapping electric double-layer effect formed by hydrogen protons on the TPPA surface, and the energy utilization efficiency is 95.95%. Moreover, TPPA-5 can purify pesticide-containing wastewater, which has the advantages of being recyclable and environmentally friendly, showing potential application value in the field of seawater desalination and steam co-generation.

Machine learning analysis of heat transfer and electroosmotic effects on multiphase wavy flow: a numerical approach

PurposeThis study aims to present a unique hybrid metaheuristic approach to solving the nonlinear analysis of hall currents and electric double layer (EDL) effects in multiphase wavy flow by merging the firefly algorithm (FA) and the water cycle algorithm (WCA).Design/methodology/approachNonlinear Hall currents and EDL effects in multiphase wavy flow are originally described by partial differential equations, which are then translated into an ordinary differential equation model. The hybrid FA-WCA technique is used to take on the optimization challenge and find the best possible design weights for artificial neural networks. The fitness function is efficiently optimized by this hybrid approach, allowing the optimal design weights to be determined.FindingsThe proposed strategy is shown to be effective by taking into account multiple variables to arrive at a single answer. The numerical results obtained from the proposed method exhibit good agreement with the reference solution within finite intervals, showcasing the accuracy of the approach used in this study. Furthermore, a comparison is made between the presented results and the reference numerical solutions of the Hall Currents and electroosmotic effects in multiphase wavy flow problem.Originality/valueThis comparative analysis includes various performance indices, providing a statistical assessment of the precision, efficiency and reliability of the proposed approach. Moreover, to the best of the authors’ knowledge, this is a new work which has not been explored in existing literature and will add new directions to the field of fluid flows to predict most accurate results.

Effect of electric field on the wetting behavior of GaInSnBiZn high-entropy alloy in NaOH aqueous solution

The GaInSnBiZn low-melting-point high-entropy alloy exhibits promising prospects for utilization in the realm of flexible electronic devices, offering a promising alternative to common binary or ternary room-temperature liquid metals. By utilizing the sessile drop method, the wetting behavior of GaInSnBiZn/SiO2 was investigated, focusing on the effects of applied voltage and NaOH solution concentration. It was revealed that the alloy's electro-wetting is primarily influenced by the generation and dissolution of the surface oxide layer, as well as the interaction of the electric double-layer effect. The optimal response voltages for achieving the fastest wetting rate were found to be 16 V, 10 V, 18 V, and 8 V in 0.5 mol/L, 1.0 mol/L, 1.5 mol/L, and 2.0 mol/L concentrations, respectively, with 18 V at 1.5 mol/L concentration identified as the optimal process selection. The spreading behavior of the alloy in low-concentration NaOH solutions followed Tanner's Law, while in the 2.0 mol/L concentration, significant repellence and wetting angle saturation were observed. The wetting process of the alloy at various stages was described using the power-law equation R = atc, while the wetting mechanism of the alloy was elucidated through the application of the Lippmann equation and the electric double-layer effect equation.

Electric Double Layer Effects in Electrocatalysis: Insights from Ab Initio Simulation and Hierarchical Continuum Modeling.

Structures of the electric double layer (EDL) at electrocatalytic interfaces, which are modulated by the material properties, the electrolyte characteristics (e.g., the pH, the types and concentrations of ions), and the electrode potential, play crucial roles in the reaction kinetics. Understanding the EDL effects in electrocatalysis has attracted substantial research interest in recent years. However, the intrinsic relationships between the specific EDL structures and electrocatalytic kinetics remain poorly understood, especially on the atomic scale. In this Perspective, we briefly review the recent advances in deciphering the EDL effects mainly in hydrogen and oxygen electrocatalysis through a multiscale approach, spanning from the atomistic scale simulated by ab initio methods to the macroscale by a hierarchical approach. We highlight the importance of resolving the local reaction environment, especially the local hydrogen bond network, in understanding EDL effects. Finally, some of the remaining challenges are outlined, and an outlook for future developments in these exciting frontiers is provided.