scholarly journals Can electric fields drive chemistry for an aqueous microdroplet?

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Hongxia Hao ◽  
Itai Leven ◽  
Teresa Head-Gordon
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Reaction Rates ◽  
Droplet Surface ◽  
Surface Reactivity ◽  
Coarse Grained ◽  
Bulk Solution ◽  
Electron Model ◽  
Field Distributions ◽  
Order Of Magnitude

AbstractReaction rates of common organic reactions have been reported to increase by one to six orders of magnitude in aqueous microdroplets compared to bulk solution, but the reasons for the rate acceleration are poorly understood. Using a coarse-grained electron model that describes structural organization and electron densities for water droplets without the expense of ab initio methods, we investigate the electric field distributions at the air-water interface to understand the origin of surface reactivity. We find that electric field alignments along free O–H bonds at the surface are ~16 MV/cm larger on average than that found for O–H bonds in the interior of the water droplet. Furthermore, electric field distributions can be an order of magnitude larger than the average due to non-linear coupling of intramolecular solvent polarization with intermolecular solvent modes which may contribute to even greater surface reactivity for weakening or breaking chemical bonds at the droplet surface.

scholarly journals Can Electric Fields Drive Chemistry for an Aqueous Microdroplet?

2021 ◽  
Author(s):  
Hongxia Hao ◽  
Itai Leven ◽  
Teresa Head-Gordon
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Water Droplet ◽  
Reaction Rates ◽  
Surface Reactivity ◽  
Bulk Solution ◽  
Excess Charge ◽  
Electronic Effects ◽  
Rate Acceleration

Abstract Reaction rates of common organic reactions have been reported to increase by one to six orders of magnitude in aqueous microdroplets compared to bulk solution, but the reasons for the rate acceleration are poorly understood. We investigate the role of electric fields at water droplet surfaces that might explain the promotion of unusual reactive chemistry, along with changes in electric field profiles as a function of excess charge to model the electrospray fragmentation process. We find that electric field alignments along free O-H bonds at the surface yield field strength distributions that are ~30 MV/cm larger on average than that found for O-H bonds in the interior of the water droplet, consistent with greater surface reactivity. We emphasize the importance of both nuclear and electronic effects at the surface, and the non-linear coupling of intramolecular solute polarization with intermolecular solvent modes, as a necessary feature for predicting the higher field strengths at water droplet surfaces.

scholarly journals Resonant collisional shielding of reactive molecules using electric fields

Science ◽  
2020 ◽  
Vol 370 (6522) ◽  
pp. 1324-1327 ◽  
Author(s):  
Kyle Matsuda ◽  
Luigi De Marco ◽  
Jun-Ru Li ◽  
William G. Tobias ◽  
Giacomo Valtolina ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Chemical Reaction ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Dipolar Interactions ◽  
Full Control ◽  
Order Of Magnitude ◽  
Quantum Science ◽  
Chemical Reaction Rates

Full control of molecular interactions, including reactive losses, would open new frontiers in quantum science. We demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field. We prepared fermionic potassium-rubidium molecules in their first excited rotational state and observed a modulation of the chemical reaction rate by three orders of magnitude as we tuned the electric field strength by a few percent across resonance. In a quasi–two-dimensional geometry, we accurately determined the contributions from the three dominant angular momentum projections of the collisions. Using the resonant features, we shielded the molecules from loss and suppressed the reaction rate by an order of magnitude below the background value, thereby realizing a long-lived sample of polar molecules in large electric fields.

scholarly journals Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nathalie Basdevant ◽  
Delphine Dessaux ◽  
Rosa Ramirez
Keyword(s):  
Molecular Dynamics ◽  
Lipid Bilayer ◽  
Electric Fields ◽  
Ionic Transport ◽  
Stationary Regime ◽  
Coarse Grained ◽  
Experimental Conditions ◽  
Current Saturation ◽  
Order Of Magnitude ◽  
Dynamics Simulations

Abstract The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore (α-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2–3 microseconds. The resulting I − V curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over ±350 mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.

scholarly journals Electric field–induced selective catalysis of single-molecule reaction

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw3072 ◽  
Author(s):  
Xiaoyan Huang ◽  
Chun Tang ◽  
Jieqiong Li ◽  
Li-Chuan Chen ◽  
Jueting Zheng ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Single Molecule ◽  
Alder Reaction ◽  
Diels Alder ◽  
Specific Chemical ◽  
Molecule Reaction ◽  
Aromatization Reaction ◽  
Order Of Magnitude ◽  
Selective Catalysis

Oriented external electric fields (OEEFs) offer a unique chance to tune catalytic selectivity by orienting the alignment of the electric field along the axis of the activated bond for a specific chemical reaction; however, they remain a key experimental challenge. Here, we experimentally and theoretically investigated the OEEF-induced selective catalysis in a two-step cascade reaction of the Diels-Alder addition followed by an aromatization process. Characterized by the mechanically controllable break junction (MCBJ) technique in the nanogap and confirmed by nuclear magnetic resonance (NMR) in bottles, OEEFs are found to selectively catalyze the aromatization reaction by one order of magnitude owing to the alignment of the electric field on the reaction axis. Meanwhile, the Diels-Alder reaction remained unchanged since its reaction axis is orthogonal to the electric fields. This orientation-selective catalytic effect of OEEFs reveals that chemical reactions can be selectively manipulated through the elegant alignment between the electric fields and the reaction axis.

scholarly journals Formation of Oriented Fibers Using Injection of PEO Solutions inside Electric Fields Defined by Two Parallel Suspended Electrodes

2011 ◽  
Vol 6 (2) ◽  
pp. 122-126
Author(s):  
Rogerio Furlan ◽  
Joel A. M. Rosado ◽  
Ana Neilde Rodrigues Da Silva
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Boundary Conditions ◽  
Electric Fields ◽  
Polyethylene Oxide ◽  
Comsol Multiphysics ◽  
Polymeric Solution ◽  
Field Distributions ◽  
Good Agreement

Formation of oriented fibers using injection of polyethylene oxide (PEO) solutions inside electric fields defined by two parallel suspended electrodes is investigated. Images of streams formed with the injection of a large amount of polymeric solution reveal good agreement with electric field distributions obtained with numerical simulation (COMSOL Multiphysics) when appropriate boundary conditions are defined. Oriented fibers with diameters in the range of hundreds of nanometers to micrometers result connected between electrodes (separated by several centimeters) and can be easily collected/transferred keeping their orientation. Fibers with this characteristic find applications in topics such as tissue and sensors engineering. Also, the fibers are flexible and can be shaped with the stylus of a profilometer.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

scholarly journals Integrating flexible electronics for pulsed electric field delivery in a vascularized 3D glioblastoma model

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Marie C. Lefevre ◽  
Gerwin Dijk ◽  
Attila Kaszas ◽  
Martin Baca ◽  
David Moreau ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Flexible Electronics ◽  
Soft Tissues ◽  
Multiphoton Microscopy ◽  
Membrane Integrity ◽  
Tumor Model ◽  
Pulsed Electric Fields ◽  
In Ovo ◽  
Cell Membrane Integrity

AbstractGlioblastoma is a highly aggressive brain tumor, very invasive and thus difficult to eradicate with standard oncology therapies. Bioelectric treatments based on pulsed electric fields have proven to be a successful method to treat cancerous tissues. However, they rely on stiff electrodes, which cause acute and chronic injuries, especially in soft tissues like the brain. Here we demonstrate the feasibility of delivering pulsed electric fields with flexible electronics using an in ovo vascularized tumor model. We show with fluorescence widefield and multiphoton microscopy that pulsed electric fields induce vasoconstriction of blood vessels and evoke calcium signals in vascularized glioblastoma spheroids stably expressing a genetically encoded fluorescence reporter. Simulations of the electric field delivery are compared with the measured influence of electric field effects on cell membrane integrity in exposed tumor cells. Our results confirm the feasibility of flexible electronics as a means of delivering intense pulsed electric fields to tumors in an intravital 3D vascularized model of human glioblastoma.

Electric-Field Effects on Reactions Between Oxides

1997 ◽  
Vol 481 ◽  
Author(s):  
Matthew T. Johnson ◽  
Shelley R. Gilliss ◽  
C. Barry Carter
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Elevated Temperatures ◽  
Ionic Current ◽  
Reaction Rates ◽  
Solid State Reactions ◽  
Interfacial Stability ◽  
Electric Field Effects ◽  
Thin Film Diffusion ◽  
Microscopy Techniques

ABSTRACTThin films of In2O3 and Fe2O3 have been deposited on (001) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples were then reacted in an applied electric field at elevated temperatures. In this type of solid-state reaction, both the reaction rate and the interfacial stability are affected by the transport properties of the reacting ions. The electric field provides a very large external driving force that influences the diffusion of the cations in the constitutive layers. This induced ionic current causes changes in the reaction rates, interfacial stability and distribution of the phases. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated in these spinel-forming systems, to gain a better understanding of the influence of an electric field on solid-state reactions.

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