Determination of the Surface Concentration of Crown Ethers in Supported Lipid Membranes by Capacitance Measurements

Langmuir ◽  
1998 ◽  
Vol 14 (9) ◽  
pp. 2573-2576 ◽  
Author(s):  
Samuel Terrettaz ◽  
Horst Vogel ◽  
Michael Grätzel
1987 ◽  
Vol 52 (2) ◽  
pp. 308-315
Author(s):  
Anastos Anastopoulos ◽  
Anastasia Christodoulou

The determination of the adsorbed film characteristics at the interface between methanolic solutions of quaternary phosphonium salts and the Hg electrode is carried out by means of time dependent capacitance measurements. The maximum surface concentration, the area per adsorbed particle and the orientation of methyltriphenyl-, cyclopropyltriphenyl-, and n-butyltriphenylphosphonium cations are derived by two methods, the first of which is free of isotherm assumptions and the second involves an adsorption isotherm obeyed by the system under examination.


MRS Bulletin ◽  
2006 ◽  
Vol 31 (7) ◽  
pp. 507-512 ◽  
Author(s):  
Atul N. Parikh ◽  
Jay T. Groves

Supported membranes represent an elegant route to designing well-defined fluid interfaces which mimic many physical-chemical properties of biological membranes. Recent years have witnessed rapid growth in the applications of physical and materials science approaches in understanding and controlling lipid membranes. Applying these approaches is enabling the determination of their structure-dynamics-function relations and allowing the design of membrane-mimetic devices. The collection of articles presented in this issue of MRS Bulletin illustrates the breadth of activity in this growing partnership between materials science and biophysics. Together, these articles highlight some of the key challenges of cellular membranes and exemplify their utility in fundamental biophysical studies and technological applications. The topics covered also confirm the importance of lipid membranes as an exciting example of soft condensed matter. We hope that this issue will serve readers by highlighting the intellectual scope and emerging opportunities in this highly interdisciplinary area of materials research.


2014 ◽  
Vol 14 (5) ◽  
pp. 617-623 ◽  
Author(s):  
Michael Hirtz ◽  
Naresh Kumar ◽  
Lifeng Chi

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Damian Dziubak ◽  
Kamil Strzelak ◽  
Slawomir Sek

Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures. It was found that adsorption of the bicelles occurs by replacement of interfacial water and it leads to formation of a double bilayer structure on the electrode surface. The resulting lipid assembly contains numerous defects and pinholes which affect the permeability of the membrane for ions and water. Significant improvement in morphology and electrochemical characteristics is achieved upon freeze–thaw treatment of the deposited membrane. The lipid assembly is rearranged to single bilayer configuration with locally occurring patches of the second bilayer, and the number of pinholes is substantially decreased. Electrochemical characterization of the lipid membrane after freeze–thaw treatment demonstrated that its permeability for ions and water is significantly reduced, which was manifested by the relatively high value of the membrane resistance.


1998 ◽  
Vol 10 (5) ◽  
pp. 295-302 ◽  
Author(s):  
Victor I. Passechnik ◽  
Tibor Hianik ◽  
Sergey A. Ivanov ◽  
Branislav Sivak

2006 ◽  
Vol 917 ◽  
Author(s):  
Shilpa Dubey ◽  
Keijing Li ◽  
Harish Bhandari ◽  
Zheng Hu ◽  
C. Heath Turner ◽  
...  

AbstractHafnium oxide ultra thin films on Si (100) are being developed to replace thermally grown SiO2 gates in CMOS devices. In this work, a specially designed Attenuated Total Reflectance - Fourier Transform Infra Red Spectroscopy (ATR-FTIR) reaction cell has been developed to observe chemisorption of hafnium (IV) t-butoxide onto a Si and Ge ATR crystal heated up to 250°C and under 1 torr of vacuum to observe the initial reaction pathways and species on the substrate surface in real time and under typical process conditions. Chemisorption spectra were compared to spectra of the liquid precursor and to spectra generated by density functional theory (DFT) calculations of liquid, monodentate and bidentate absorbed precursor. An asymmetric stretching mode located at ~1017 cm-1 present in the chemisorbed spectra but not in the liquid spectra indicates that the adsorbed hafnium containing group is prevalent as a bidentate ligand according to calculations. Surface concentration of the chemisorbed species was dependant on the substrate temperature and precursor partial pressure allowing for determination of heats of adsorption which was 26.5 kJ/mol on Si.


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