scholarly journals Unveiling the interaction of DNA–octadecylamine at the air–water interface by ultraviolet-visible reflection spectroscopy

RSC Advances ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 5872-5879 ◽  
Author(s):  
A. Mora-Boza ◽  
T. Lopes-Costa ◽  
F. Gámez ◽  
J. M. Pedrosa
Keyword(s):  
Surface Pressure ◽  
Water Interface ◽  
Reflection Spectroscopy ◽  
Air Water Interface ◽  
Pressure Area

In this work, ultraviolet-visible reflection spectroscopy is proposed as a technique that, in combination with classical surface pressure–area isotherms, allows to study in situ the adsorption of DNA to octadecylamine monolayers.

scholarly journals Synthesis and monolayer film of a series of new twin-tailed gemini cationic surfactants at the air/water interface

2008 ◽  
Vol 6 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Zhi Chen ◽  
Yujun Feng ◽  
Dongliang Zhou ◽  
Puxin Zhu ◽  
Dacheng Wu
Keyword(s):  
Surface Pressure ◽  
Gemini Surfactants ◽  
Limited Area ◽  
Initial Surface ◽  
Water Interface ◽  
Spacer Length ◽  
Collapse Pressure ◽  
Initial Area ◽  
Air Water Interface ◽  
Pressure Area

AbstractA series of new dimeric surfactants, twin-tailed gemini surfactants, 2(12)-s-2(12), were successfully prepared and characterized, and their monolayer films investigated by the measurement of surface pressure-area (π-A) and surface pressure-time (π-t) isotherms at the air/water interface by a Langmuir film balance. Compared to their monomeric counterparts, their collapse pressure (γcollapse) is smaller, whilst all the molecular area parameters are larger. The limited area (Alimited) and the initial area (Ainitial) of these twin-tailed gemini surfactants change with increasing spacer length s, and the surface pressure decreases with increasing time. It was also found that the higher the initial surface pressure, the larger the attenuation.

scholarly journals MONOLAYER CHARACTERISTICS OF PYRENE MIXED WITH STEARIC ACID AT THE AIR–WATER INTERFACE

2008 ◽  
Vol 15 (03) ◽  
pp. 287-293 ◽  
Author(s):  
MD. N. ISLAM ◽  
D. BHATTACHARJEE ◽  
SYED ARSHAD HUSSAIN
Keyword(s):  
Phase Separation ◽  
Stearic Acid ◽  
Surface Pressure ◽  
Water Interface ◽  
Present Communication ◽  
Mixed Monolayer ◽  
Air Water Interface ◽  
Mixed Films ◽  
Pressure Area

In the present communication, the monolayer characteristics of pyrene mixed with stearic acid (SA) at the air–water interface have been reported. The monolayer properties are investigated by recording and analyzing the surface pressure–area per molecule isotherm (π–A) of the pyrene–SA mixed films. It is observed that the pyrene and SA are miscible in the mixed monolayer. This miscibility/nonideality leads to phase separation between the constituent components (pyrene and SA). BAM image of the mixed monolayer confirms the miscibility or nonideal mixing at the mixed monolayer.

Polymers containing phtalimidoalkyl groups in the side chains. effect of the alkyl groups in monolayers at the airwater interface

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Ligia Gargallo ◽  
Angel Leiva ◽  
Alvaro González ◽  
Luz Alegría ◽  
Claudia Sandoval ◽  
...  
Keyword(s):  
Surface Pressure ◽  
Scaling Laws ◽  
Surface Concentration ◽  
Water Interface ◽  
Static Elasticity ◽  
Alkyl Groups ◽  
Air Water Interface ◽  
Pressure Area ◽  
Methylene Groups ◽  
Total Surface Free Energy

AbstractSurface activity of poly(methacrylate)s containing phthalimidoalkyl groups was studied. Surface pressure-area isotherms ( -A) at the air-water interface were determined. These polymers form stable and condensed monolayers. The monolayers are more condensed and the limiting surface area A0 values decrease when the number of the methylene groups in the lateral chains increases. Surface pressure variation at the semidilute region of the monolayers was expressed in terms of the scaling laws as power function of the surface concentration. The static elasticity εo and the exponent of the excluded volume υ were determined. The hydrophobicity degree of polymers was estimated from the determination of the total surface free energy values by wettability measurements. Molecular dynamic simulation (MDS) was performed in order to explain the experimental behavior of polymers at the air-water interface.

scholarly journals Hysteresis of Isotherms of Mixed Monolayers of N-Octadecyl-N′-phenylthiourea and Stearic Acid at Air/Water Interface

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Siji Sudheesh ◽  
Jamil Ahmad ◽  
Girija S. Singh
Keyword(s):  
Stearic Acid ◽  
Surface Pressure ◽  
Surface Film ◽  
Langmuir Monolayers ◽  
The Other ◽  
Water Interface ◽  
Octadecanoic Acid ◽  
Air Water Interface ◽  
Pressure Area ◽  
Limiting Surface

Surface pressure area isotherms of Langmuir monolayers formed by spreading mixed solutions of varying concentrations of N-octadecyl-N′-phenylthiourea (OPT) and octadecanoic acid or stearic acid (SA) over air-water interface are described. Examination of the hysteresis behavior and an analysis of the limiting area per molecule of the isotherms show that when the spread solution has an excess of OPT, the limiting surface area is consistent with a monolayer composed of equimolar amounts of the two components. This indicates that any excess thiourea, which on its own does not form a stable monolayer, is squeezed out and is not part of the monolayer. On the other hand, when the spreading mixture has an excess of SA over OPT, the isotherm indicates that the entire originally spread material is incorporated into the surface film. In this case, the values of area/molecule indicate that the monolayer is composed of SA : OPT complex with a ratio of 1 : 1 together with the excess SA remaining in the monolayer.

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