Energy and entropy of formation of crystalline 1-pentadecanoic acid from the ideal gaseous monolayer at the air/water interface

Langmuir ◽  
1992 ◽  
Vol 8 (2) ◽  
pp. 599-601 ◽  
Author(s):  
N. R. Pallas ◽  
B. A. Pethica
Keyword(s):  
Water Interface ◽  
Pentadecanoic Acid ◽  
Air Water Interface ◽  
Entropy Of Formation ◽  
The Ideal

Static and dynamic properties of pentadecanoic acid monolayers at the air-water interface

Langmuir ◽  
1986 ◽  
Vol 2 (3) ◽  
pp. 349-354 ◽  
Author(s):  
Yen Lane. Chen ◽  
Masahito. Sano ◽  
Masami. Kawaguchi ◽  
Hyuk. Yu ◽  
George. Zografi
Keyword(s):  
Dynamic Properties ◽  
Water Interface ◽  
Pentadecanoic Acid ◽  
Air Water Interface

The influence of electrolytes on gaseous monolayers II. Ionized films

1955 ◽  
Vol 232 (1189) ◽  
pp. 159-172 ◽  
Keyword(s):  
Surface Potential ◽  
Quaternary Ammonium ◽  
Alkyl Chain ◽  
Electrolyte Concentration ◽  
Ammonium Ion ◽  
Water Interface ◽  
Ammonium Halides ◽  
Air Water Interface ◽  
Good Agreement ◽  
The Ideal

An equation of state for a charged monolayer spread on an aqueous solution of a 1:1 electrolyte at 20°C in the absence of cohesive interactions has been derived, namely II = 2 kT / A-A o + 6.10√ c cosh sinh -1 133/ A √ c 6.10√ c . It has been found to apply to soluble charged films at hydrocarbon/water interfaces. In the case of insoluble monolayers of both alkyl quaternary ammonium halides and sodium alkyl sulphates at the hydrocarbon/water interface there is evidence of considerable ( ~50 %) ion-pair association, and this appears to be even further enhanced at the air/water interface at least for sulphate films. Surface potentials, measured by both the radioactive electrode and vibrating plate condenser techniques have been found to be in good agreement. The surface potential of sulphate monolayers in contrast to the ideal behaviour of quaternary ammonium films has been found to be dependent not only on the electrolyte concentration and film area but also on the nature of the interface, the nature of the substrate and at the air/water interface on the chain length. This has been attributed to a reorientation of the film molecules at the interface. Differences in the surface potential behaviour of sulphate and quaternary ammonium films are explained by suggesting that whereas with the sulphate film restricted rotation about the C—O bond can lead to different configurations of the sulphate ion with respect to the alkyl chain, only one configuration is possible for the symmetrical quaternary ammonium ion. Surface potential evidence indicates that contrary to what has been suggested previously, sulphate monolayers are completely dissociated in the acid-base sense.

Morphology of pentadecanoic acid monolayers at the air/water interface studied by BAM

1992 ◽  
Vol 4 (6) ◽  
pp. 419-424 ◽  
Author(s):  
Dirk Honig ◽  
Gernot A. Overbeck ◽  
Dietmar Mobius
Keyword(s):  
Water Interface ◽  
Pentadecanoic Acid ◽  
Air Water Interface

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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