Direct deposition of two nanomaterials with the same surface charge using a liquid–liquid interface

Nanoscale ◽  
2012 ◽  
Vol 4 (13) ◽  
pp. 3857 ◽  
Author(s):  
Jun Matsui ◽  
Toshiaki Shibata ◽  
Takahiro Yokoyama ◽  
Akito Masuhara ◽  
Hitoshi Kasai ◽  
...  
Keyword(s):  
Surface Charge ◽  
Liquid Interface ◽  
Direct Deposition

Electrokinetics at liquid/liquid interfaces

2011 ◽  
Vol 684 ◽  
pp. 163-191 ◽  
Author(s):  
Andrew J. Pascall ◽  
Todd M. Squires
Keyword(s):  
Liquid Metal ◽  
Surface Charge ◽  
Electrophoretic Mobility ◽  
Double Layer ◽  
Physical Mechanism ◽  
Liquid Interface ◽  
Liquid Interfaces ◽  
Electrical Stress ◽  
Dielectric Liquids ◽  
Solid Liquid

AbstractElectrokinetic effects at liquid/liquid interfaces have received considerably less attention than at solid/liquid interfaces. Because liquid/liquid interfaces are generally mobile, one might expect electrokinetic effects over a liquid/liquid interface to be faster than over an equivalent solid surface. The earliest predictions for the electrophoretic mobility of charged mercury drops – distinct approaches by Frumkin, along with Levich, and Booth – differed by $O(a/ {\lambda }_{D} )$, where $a$ is the radius of the drop and ${\lambda }_{D} $ is the Debye length. Seeking to reconcile this rather striking discrepancy, Levine & O’Brien showed double-layer polarization to be the key ingredient. Without a physical mechanism by which electrokinetic effects are enhanced, however, it is difficult to know how general the enhancement is – whether it holds only for liquid metal surfaces, or more generally, for all liquid/liquid surfaces. By considering a series of systems in which a planar metal strip is coated with either a liquid metal or liquid dielectric, we show that the central physical mechanism behind the enhancement predicted by Frumkin is the presence of an unmatched electrical stress upon the electrolyte/liquid interface, which establishes a Marangoni stress on the droplet surface and drives it into motion. The source of the unbalanced electrokinetic stress on a liquid metal surface is clear – metals represent equipotential surfaces, so no field exists to drive an equal and opposite force on the surface charge. This might suggest that liquid metals represent a unique system, since dielectric liquids can support finite electric fields, which might be expected to exert an electrical stress on the surface charge that balances the electric stress. We demonstrate, however, that electrical and osmotic stresses on relaxed double layers internal to dielectric liquids precisely cancel, so that internal electrokinetic stresses generally vanish in closed, ideally polarizable liquids. The enhancement predicted by Frumkin for liquid mercury drops can thus be expected quite generally over ideally polarizable liquid drops. We then reconsider the electrophoretic mobility of spherical drops, and reconcile the approaches of Frumkin and Booth: Booth’s neglect of double-layer polarization leads to a standard electro-osmotic flow, without the enhancement, and Frumkin’s neglect of the detailed double-layer dynamics leads to the enhanced electrocapillary motion, but does not capture the (sub-dominant) electrophoretic motion. Finally, we show that, while the electrokinetic flow over electrodes coated with thin liquid films is $O(d/ {\lambda }_{D} )$ faster than over solid/liquid interfaces, the Dukhin number, $\mathit{Du}$, which reflects the importance of surface conduction to bulk conduction, generally increases by a smaller amount [$O(d/ L)$], where $d$ is the thickness of film and $L$ is the length of the electrode. This suggests that liquid/liquid interfaces may be utilized to enhance electrokinetic velocities in microfluidic devices, while delaying the onset of high-$\mathit{Du}$ electrokinetic suppression.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

RHEOLOGICAL INVESTIGATION OF MESOMORPHIC LAYERS FORMED AT THE LIQUID/LIQUID INTERFACE

1979 ◽  
Vol 40 (C3) ◽  
pp. C3-447-C3-450 ◽  
Author(s):  
H. S. KIELMAN ◽  
P. J. F. VAN STEEN
Keyword(s):  
Liquid Interface

Rapid, efficient and dose-controlled delivery of liquid aerosol to pulmonary cells cultured at the air-liquid interface

Pneumologie ◽  
2011 ◽  
Vol 65 (12) ◽  
Author(s):  
M Selmansberger ◽  
AG Lenz ◽  
M Schmidmeir ◽  
O Eickelberg ◽  
T Stoeger ◽  
...  
Keyword(s):  
Liquid Interface ◽  
Controlled Delivery ◽  
Pulmonary Cells ◽  
Air Liquid Interface ◽  
Cells Cultured

Zwischen Luft und Wasser – Air-Liquid-Interface-Kulturen als In-vitro-Modell des Respirationstrakts

2020 ◽  
Author(s):  
S. Runft ◽  
L. Burigk ◽  
A. Lehmbecker ◽  
K. Schöne ◽  
D. Waschke ◽  
...  
Keyword(s):  
Liquid Interface ◽  
Air Liquid Interface
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