The electrodynamics of micellar ions in nonpolar liquids are well understood for the case that a voltage is applied or switched off. In this work, the electrodynamics of charged inverse micelles (CIMs) are studied when the applied voltage is switched to the opposite polarity, which is relevant for applications such as electrophoretic displays and liquid toner printing. Transient current measurements are used to characterize the switching of CIMs formed in a solution of surfactant polyisobutylene succinimide in n-dodecane. For reverse voltages with amplitude below 10V the measurements are in good agreement with a drift and diffusion model, confirming the established understanding of CIMs in nonpolar liquids. When the charge content is high, the reversal current shows a characteristic peak which is explained on the basis of dynamic space-charge effects. However, for reverse voltages larger than 10V, the transient currents are influenced by electrohydrodynamic flow in the liquid causing the CIMs to switch faster than predicted by the model. The occurrence of electrohydrodynamic flow is verified by optical tracking of tracer particles. Also, when the polarizing voltage is applied for longer times, an additional current peak emerges which is due to the accumulation of newly generated charges at the electrodes.
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http://dx.doi.org/10.1016/j.jcis.2015.07.039 | DOI Listing |
Neuroimage
January 2025
Dept. of Electrical and Computer Engineering, Worcester Polytechnic Institute, Worcester, MA, USA.
A fast BEM (boundary element method) based approach is developed to solve an EEG/MEG forward problem for a modern high-resolution head model. The method utilizes a charge-based BEM accelerated by the fast multipole method (BEM-FMM) with an adaptive mesh pre-refinement method (called b-refinement) close to the singular dipole source(s). No costly matrix-filling or direct solution steps typical for the standard BEM are required; the method generates on-skin voltages as well as MEG magnetic fields for high-resolution head models within 90 seconds after initial model assembly using a regular workstation.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Laboratorio de Espectroscopía Atómica y Molecular (LEAM), Universidad Industrial de Santander, Colombia.
Illite mineral is present in shale rocks, and its wettability behavior is significant for the oil and gas industry. In this work, the pH effects on the affinity between the (001) and (010) crystallographic planes of illite K(SiAl)(AlMg)O(OH) and direct and inverse emulsions were studied using molecular dynamics simulations. To develop the simulations, an atomistic model of illite was constructed following Löwenstein's rule.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin, Heilongjiang, 150025, China.
Lithium-sulfur batteries (LSBs) offer high energy density and environmental benefits hampered by the shuttle effect related to sluggish redox reactions of long-chain lithium polysulfides (LiPSs). However, the fashion modification of the d-band center in separators is still ineffective, wherein the mechanism understanding always relies on theoretical calculations. This study visibly probed the evolution of the Co 3d-band center during charge and discharge using advanced inverse photoemission spectroscopy/ultraviolet photoemission spectroscopy (IPES/UPS), which offers reliable evidence and are consistent well with theoretical calculations.
View Article and Find Full Text PDFChembiochem
December 2024
Nankai University, Analytical Sciences, No. 94, Weijin Road, 300071, Tianjin, CHINA.
Smart shape-memory DNA hydrogels, which can respond to various types of external stimuli and undergo macroscopic shape deformations, have shown great potential in various applications. By constructing free-standing films, the deformation and response properties of these hydrogels can be further enhanced, and visualized deformation can be achieved. However, DNA hydrogels that can exhibit rapid and high-degree shape deformations, such as the inverse shape deformations, are still lacking.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Institute of Organic Chemistry and Biochemistry, Computational Chemistry, Flemingovo nam. 2, 16610, Prague 6, CZECHIA.
The binding free energy of hydrogen-bonded complexes is generally inversely proportional to the solvent dielectric constant. This occurs because the solvent-accessible surface area of the complex is always smaller than that of the individual subsystems, leading to a reduction in solvation energy. The present study explores the potential for stabilizing hydrogen-bonded complexes in a solvent with higher polarity.
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