scholarly journals Investigations of the Air-Water Interface: A Structural Analysis of Metallic Surface Films and Aquatic Surface Films by Comparative Microscopy

2000 ◽  
Author(s):  
Randall Smith
Keyword(s):  
Structural Analysis ◽  
Metallic Surface ◽  
Surface Films ◽  
Water Interface ◽  
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.

Ecophysiological and Phylogenetic Studies ofNevskia ramosa in Pure Culture

1998 ◽  
Vol 64 (5) ◽  
pp. 1890-1894 ◽  
Author(s):  
Heike St�rmeyer ◽  
J�rg Overmann ◽  
Hans-Dietrich Babenzien ◽  
Heribert Cypionka
Keyword(s):  
Nitrogenase Activity ◽  
Hydrophobic Surface ◽  
Surface Films ◽  
Organic Substrates ◽  
Water Interface ◽  
Phylogenetic Studies ◽  
Air Water Interface ◽  
Pure Cultures ◽  
Close Relatives ◽  
First Time

ABSTRACT During the last 100 years, the neuston bacterium Nevskia ramosa has been described several times. This bacterium forms conspicuous rosette-like microcolonies at the air-water interface. In this study, pure cultures of Nevskia ramosawere obtained for the first time, from a bog lake (strain Soe1, DSMZ 11499T) and a freshwater ditch (strain OL1, DSMZ 11500). The isolates showed special adaptations to life in the epineuston. They formed hydrophobic surface films with a dull appearance. N. ramosa is sensitive to UV radiation but revealed a very effective photorepair mechanism. Exposure to light at a wavelength of 350 nm after UV treatment raised the number of surviving cells by several orders of magnitude. The isolates grew with a broad range of organic substrates. Surface films were formed only in the absence of combined nitrogen; however, nitrogenase activity was not detected. It appears that during growth at the air-water interface the cells benefit from trapping ammonia from the air. The G+C content of the DNA was 67.8 and 69.0 mol% for strains Soe1 and OL1, respectively. The slight difference was confirmed by enterobacterial repetitive intergenic consensus PCR. The 16S rRNA sequences revealed 99.2% similarity. Thus, both isolates belong to the same species. The phylogenetic analysis indicated that Nevskia is a member of the gamma-subclass Proteobacteria that has no known close relatives.

Multi-Layers Thin Films of Acetalized Poly(Vinyl Alcohol) Derivatives Obtained by the LB Method and Their Opto-Electronic Properties

1989 ◽  
Vol 175 ◽  
Author(s):  
Kiyoshi Oguchi ◽  
Yasuhiko Yokoh ◽  
Kohei Sanui ◽  
Naoya Ogata
Keyword(s):  
Vinyl Alcohol ◽  
Second Harmonic ◽  
Repeat Unit ◽  
Single Layer ◽  
Degree Of Polymerization ◽  
Poly Vinyl Alcohol ◽  
Surface Films ◽  
Water Interface ◽  
Number Of Layers ◽  
Air Water Interface

AbstractThe formation of surface films of acetalized poly(vinyl alcohol)s at the air/water interface has been investigated in terms of the structure of the transferred films, after transfer of these surface films to solid substrates by means of the Langmuir-Blodgett technique. Furthermore, their electron beam exposure characteristics and non-linear optical properties were measured. It was found that the monolayers of acetalized poly(vinyl alcohol)s having aliphatic side chaines gave stable surface films with a limiting area of ca. 0.3nm2/average repeat unit, irrespective of the side-chain length and the degree of polymerization of the starting poly(vinyl alcohol). The surface films could be deposited onto various substrates with deposition ratios of 1.0. The resulting multilayers were Y type. The thickness of the multilayers was proportional to the number of layers, and the single-layer thickness increased with increasing sidechain length. The surface wettability of the multilayers changed alternatingly, depending on whether the number of layers was even or odd. These results indicated that the surface films were monolayers of polymers, with hydrophilic main chains spread over the air/water interface and hydrophobic side chains directed approximately normal to the interface. The transferred films maintained the oriented structure of the monolayers at the interface. The acetalized poly(vinyl alcohol)s prepared by the LB technique is adaptable as a high resolution negative-type EB resist. And the second harmonic generation (SHG) of some acetalized poly(vinyl alcohol)s was observed by LB method and by electric field poling method.

scholarly journals Tip-enhanced Raman spectroscopy for structural analysis of two-dimensional covalent monolayers synthesized on water and on Au (111)

2019 ◽  
Vol 10 (42) ◽  
pp. 9673-9678 ◽  
Author(s):  
Li-Qing Zheng ◽  
Marco Servalli ◽  
A. Dieter Schlüter ◽  
Renato Zenobi
Keyword(s):  
Raman Spectroscopy ◽  
Structural Analysis ◽  
Metal Surface ◽  
Water Interface ◽  
Two Dimensional ◽  
Ambient Conditions ◽  
Air Water Interface ◽  
Tip Enhanced Raman Spectroscopy ◽  
2D Polymer

Two-dimensional covalent monolayers synthesized at an air/water interface were structurally analyzed by tip-enhanced Raman spectroscopy (TERS). Finally, on-metal surface synthesis of a 2D polymer was demonstrated under ambient conditions.

In Situ Measurement of the FT-IR Spectra of Phospholipid Monolayers at the Air/Water Interface

1988 ◽  
Vol 42 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Richard A. Dluhy ◽  
Norman A. Wright ◽  
Peter R. Griffiths
Keyword(s):  
Detailed Examination ◽  
In Situ Measurement ◽  
Surface Films ◽  
Water Interface ◽  
Monolayer Films ◽  
Air Water Interface ◽  
Monomolecular Films ◽  
Acyl Chains ◽  
Ft Ir

External reflection Fourier transform infrared spectroscopy has been applied to the in situ measurement of the infrared spectra of insoluble phospholipid monolayer films that were spread at the air/water interface. The spreading conditions for the phospholipids [1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)] were chosen to mimic those of liquid-condensed and liquid-expanded surface films, respectively. It is shown that the infrared reflection spectra can identify vibrations due to the hydrocarbon acyl chains, carbonyl ester, and phosphate groups for these monolayer films on water. Detailed examination of the frequencies and polarization properties of the C-H stretching region shows that the liquid-condensed DSPC acyl chains are in a rigid, mostly all-trans configuration, while the liquid-expanded DMPC acyl chains are highly fluid. The spectra demonstrate that the external reflection FT-IR experiment can differentiate between the physical conformation of monomolecular films when water is used as a reflective substrate.

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