Surface Characterization of Colloidal Nanoparticles by Second Harmonic Scattering: Surface Potential and Interfacial Water Order

2019 ◽  
Author(s):  
Arianna Marchioro ◽  
Marie Bischoff ◽  
Sylvie Roke
Keyword(s):  
Surface Potential ◽  
Surface Characterization ◽  
Second Harmonic ◽  
Colloidal Nanoparticles ◽  
Interfacial Water ◽  
Second Harmonic Scattering

In-Situ Characterization of Oxide Films on Liquid Alkali Metals Using Second Harmonic Generation (SHG)

1996 ◽  
Vol 451 ◽  
Author(s):  
H. Tostmann ◽  
D. Nattland ◽  
W. Freyland
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Alkali Metals ◽  
Surface Characterization ◽  
Second Harmonic ◽  
Pure Metal ◽  
Temperature Dependent ◽  
Characterization Methods

ABSTRACTThe experiments described in this paper clearly show that Second Harmonic Generation (SHG) may be used as a sensitive tool for detecting oxide impurities at interfaces not accessible for usual surface characterization methods. As a striking feature, one peak in the temperature dependent SH intensity is observed for liquid potassium and five peaks for liquid cesium. The occurrence of these peaks cannot be understood in terms of the nonlinear optical properties of the pure metal. By varying the oxygen content present in the melt it can be shown that these peaks must be attributed to the presence of oxide impurities segregating at the interface. In addition it is shown that the presence of oxides at the interface inert sapphire - molten alkali metal significantly alters the structure of the sapphire surface finally leading to corrosion visible even by the eye.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Direct Measurement of Charge Reversal on Lipid Bilayers using Heterodyne-Detected Second Harmonic Generation Spectroscopy

2019 ◽  
Author(s):  
HanByul Chang ◽  
Paul Ohno ◽  
Yangdongling Liu ◽  
Franz Geiger
Keyword(s):  
Lipid Bilayers ◽  
Surface Potential ◽  
Second Harmonic ◽  
Fluid Phase ◽  
Cationic Polyelectrolyte ◽  
Charge Reversal ◽  
Buried Interfaces ◽  
Phase Transition Temperatures ◽  
Complementary Techniques ◽  
Order Susceptibility

We report the detection of charge reversal induced by the adsorption of a cationic polyelectrolyte, poly(allylamine) hydrochloride (PAH), to buried supported lipid bilayers (SLBs), used as idealized model biological membranes. We observe changes in the surface potential in isolation from other contributors to the total SHG response by extracting the phase-shifted potential-dependent third-order susceptibility from the overall SHG signal. We demonstrate the utility of this technique in detecting both the sign of the surface potential and the point of charge reversal at buried interfaces without any prior information or complementary techniques<i>.</i>Furthermore, isolation of the second-order susceptibility contribution from the overall SHG response allows us to directly monitor changes in the Stern Layer. Finally, we characterize the Stern and Diffuse Layers over single-component SLBs formed from three different zwitterionic lipids of different gel-to-fluid phase transition temperatures (T<sub>m</sub>s). We determine whether the surface potential changes with the physical phase state (gel, transitioning, or fluid) of the SLB and incorporate 20 percent of negatively charged lipids to the zwitterionic SLB to investigate how the surface potential changes with surface charge.

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