scholarly journals Inhomogeneity of Interfacial Electric Fields at Vibrational Probes on Electrode Surfaces

2020 ◽  
Vol 6 (2) ◽  
pp. 304-311 ◽  
Author(s):  
Zachary K. Goldsmith ◽  
Maxim Secor ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electric Fields ◽  
Electrode Surfaces

Measurement of electric fields at electrode surfaces

1965 ◽  
Vol 1 (4) ◽  
pp. 110 ◽  
Author(s):  
J.M. Meek ◽  
M.M.C. Collins
Keyword(s):  
Electric Fields ◽  
Electrode Surfaces

Self and Directed Colloidal Assembly on Patterned Electrodes

2005 ◽  
Author(s):  
P. Bahukudumbi ◽  
Michael A. Bevan ◽  
Ali Beskok
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Colloidal Particle ◽  
Three Dimensional ◽  
Directed Assembly ◽  
Ordered Structures ◽  
Colloidal Assembly ◽  
Electrode Surfaces ◽  
External Electric Fields ◽  
Potential Energy Landscapes

Clustering of colloidal particles near an electrode surface during and after electrophoretic deposition has been reported in the literature [1, 2, 3, 4]. The aggregation of colloidal particles has made the precise assembly of two and three dimensional colloidal crystals possible. In this paper, we demonstrate the use of external electric fields to sensitively tune the interactions between colloidal particles to form ordered structures. The directed assembly of colloidal particles on patterned electrode surfaces is also investigated as a means of building three-dimensional nanostructures. Finally, a new method to map potential energy landscapes of templated substrates using a diffusing colloidal particle as a sensitive local energy probe is described.

scholarly journals Bacterial handling under the influence of non-uniform electric fields: dielectrophoretic and electrohydrodynamic effects

2008 ◽  
Vol 80 (4) ◽  
pp. 627-638 ◽  
Author(s):  
Flavio H. Fernádez-Morales ◽  
Julio E. Duarte ◽  
Josep Samitier-Martí
Keyword(s):  
Electric Fields ◽  
Microelectrode Array ◽  
Viscous Drag ◽  
Liquid Motion ◽  
Dielectrophoretic Force ◽  
Electrode Surfaces ◽  
Biological Objects ◽  
Viscous Drag Force ◽  
Lift Off ◽  
Positive Dielectrophoresis

This paper describes the modeling and experimental verification of a castellated microelectrode array intended tohandle biocells, based on common dielectrophoresis. The proposed microsystem was developed employing platinumelectrodes deposited by lift-off, silicon micromachining, and photoresin patterning techniques. Having fabricated the microdevice it was tested employing Escherichia coli as bioparticle model. Positive dielectrophoresis could be verified with the selected cells for frequencies above 100 kHz, and electrohydrodynamic effects were observed as the dominant phenomena when working at lower frequencies. As a result, negative dielectrophoresis could not be observed because its occurrence overlaps with electrohydrodynamic effects; i.e. the viscous drag force acting on the particles is greater than the dielectrophoretic force at frequencies where negative dielectrophoresis should occur. The experiments illustrate the convenience of this kind of microdevices to micro handling biological objects, opening the possibility for using these microarrays with other bioparticles. Additionally, liquid motion as a result of electrohydrodynamic effects must be taken into account when designing bioparticle micromanipulators, and could be used as mechanism to clean the electrode surfaces, that is one of the most important problems related to this kind of devices.

CO2 Reduction Catalysts on Gold Electrode Surfaces Influenced by Large Electric Fields

2018 ◽  
Vol 140 (50) ◽  
pp. 17643-17655 ◽  
Author(s):  
Melissa L. Clark ◽  
Aimin Ge ◽  
Pablo E. Videla ◽  
Benjamin Rudshteyn ◽  
Christopher J. Miller ◽  
...  
Keyword(s):  
Electric Fields ◽  
Gold Electrode ◽  
Co2 Reduction ◽  
Electrode Surfaces ◽  
Reduction Catalysts

AC Electrokinetic Pumps for Micro/NanoFluidics

2004 ◽  
Author(s):  
Junqing Wu ◽  
Gaurav Soni ◽  
Dazhi Wang ◽  
Carl D. Meinhart
Keyword(s):  
Electric Fields ◽  
Fluid Motion ◽  
Lab On A Chip ◽  
Dna Amplification ◽  
Aqueous Fluid ◽  
Working Fluid ◽  
High Frequencies ◽  
Electrode Surfaces ◽  
Ac Electric Fields ◽  
Micro Channels

We have developed micropumps for microfluidics that use AC electric fields to drive aqueous fluid motion through micro channels. These pumps operate at relatively low voltages (~5–10Vrms), and high frequencies (~100kHz). They have several distinct advantages over the DC electrokinetic pumps. The low voltages make the pumps well suited for a wide variety of biosensor and “Lab-on-a-Chip” applications (e.g. PCR chip for DNA amplification). The high frequencies minimize electrolysis, so that bubbles do not form on the electrode surfaces, and do not contaminate the working fluid. The pumps can also be used as active valves or precision micro-dispensers.

scholarly journals Photorefractive Effect in NLC Cells Caused by Anomalous Electrical Properties of ITO Electrodes

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 900
Author(s):  
Atefeh Habibpourmoghadam
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Indium Tin Oxide ◽  
Photorefractive Effect ◽  
Optical Power ◽  
Electrode Surfaces ◽  
Ito Film ◽  
Dc Electric Field ◽  
Spr Effect ◽  
Optically Induced

In a pure nematic liquid crystal (NLC) cell, optically induced charge carriers followed by transports in double border interfaces of orientant/LC and indium-tin-oxide (ITO)/orientant (or LC) can cause removal of screening of the static electric field inside the LC film. This is called surface photorefractive effect (SPR), which induces director field reorientation at a low DC electric field beyond the threshold at a reduced Fréedericksz transition and, as a result, a modulation of the LC effective refractive index. The studies conducted on the photoinduced opto-electrical responses in pure nematic LC cells biased with uniform static DC electric fields support the SPR effect (attributed to the photoelectric activation of the double interfaces). The SPR effect was further studied in LC cells with photoresponsive substrates, which act as a source of a bell-shaped electric field distribution in the LC film if no ITO electrode was employed. In an equipped cell with ITO, the photovoltaic electric field induces charge carrier redistribution in the ITO film, hence the SPR effect. This paper is aimed at highlighting all the evidences supporting ITO film as one of the fundamental sources of the SPR effect in pure NLC cells under the condition of applying low optical power and low DC voltage. An optically induced fringe electric field stemming from inhomogeneous photo-charge profiles near the electrode surfaces is expected in the LC film due to the semiconducting behavior of the ITO layer.

Sensitive, Non-Intrusive, In Situ Measurements of Plasma Electric Fields

1983 ◽  
Vol 29 ◽  
Author(s):  
Richard A Gottscho ◽  
Cameron A. Moore ◽  
Glenn P. Davis
Keyword(s):  
Electric Fields ◽  
High Spatial Resolution ◽  
Band System ◽  
Absolute Measurement ◽  
Laser Induced Fluorescence ◽  
Rf Discharge ◽  
Electrode Surfaces ◽  
Charged Particle Transport ◽  
A New Technique

ABSTRACTWe report a new technique for the in situ, non-intrusive, and sensitive measurement of plasma electric fields with high spatial resolution. Fields as small as 40 V/cm can be characterized by spectrally resolving laser-induced fluorescence from Stark-mixed parity levels. The technique is demonstrated by exciting the A1 11−X 1Σ+ band system of BC1, produced in an rf discharge through BCI3. The characterization and absolute measurement of sheath fields, which have been elusive, are now possible. These fields are preeminent in governing charged particle transport to and between electrode surfaces and in maintaining the glow discharge.

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