scholarly journals Surface properties of some carotenoids spread in monolayers at the air/water interface. Experimental and computational approach

2006 ◽  
Vol 4 (3) ◽  
pp. 489-501
Author(s):  
Ossi Horovitz ◽  
Gheorghe Tomoaia ◽  
Csaba Racz ◽  
Aurora Mocanu ◽  
Liviu-Dorel Bobos ◽  
...  
Keyword(s):  
Surface Properties ◽  
Dipole Moments ◽  
State Equation ◽  
Interaction Parameters ◽  
Water Interface ◽  
Molecular Area ◽  
Collapse Pressure ◽  
Pressure Surface ◽  
Air Water Interface ◽  
Β Carotene

AbstractThe surface pressure versus molecular area isotherms of some carotenoids: β,β-carotene-4-one (echinenone, ECH), β,β-carotene-4,4′-dione (canthaxanthin, CAN) and 4,4′-diapo-ω,ω-carotene-4,4′-dial (APO), spread at the air/water interface, are reported. A van der Waals type state equation is used to describe the high molecular area portions of the compression isotherms and interaction parameters within monolayers are derived. Quantum chemical semi-empirical SCF MO calculations (AM1 and PM3) are performed for the optimized geometries of molecules and dipole moments are calculated. Similar theoretical magnitudes are obtained by both methods. Surface properties, like collapse pressure, surface compressional modulus and interaction parameters are discussed in terms of dipole-dipole interactions, and correlations with the calculated quantities for the carotenoid molecules are analyzed. The orientation of the different carotenoid molecules in the monolayer is discussed.

Molecular Organization in Langmuir Films of Dichroic Azo DyeLiquid Crystal Mixtures. II. Surface Potential Measurements

2003 ◽  
Vol 58 (2-3) ◽  
pp. 97-102 ◽  
Author(s):  
T. Martynski ◽  
A. Biadasz ◽  
D. Bauman
Keyword(s):  
Surface Potential ◽  
Dipole Moments ◽  
Langmuir Films ◽  
Molecular Organization ◽  
Water Interface ◽  
Molecular Area ◽  
Effective Dipole Moment ◽  
Air Water Interface ◽  
Two Component ◽  
Surface Potential Measurements

Two-component films of 4-octyl-4’-cyanobifenyl (8CB) and non-amphiphilic azo dye (1) at different molar fractions were studied at the air-water interface on the basis of the surface potentialmean molecular area dependence recorded simultaneously with the surface pressure-mean molecular area isotherm. Conventional Langmuir technique was used to form 1/8CB (guest-host) films during reduction and expansion of an area occupied by the molecules. From the surface potential value the effective dipole moment in the first monolayer formed on the water was calculated. Moreover, the number of dipole moments directed to the air with respect to those directed towards the water was estimated. A model of the microscopic polar ordering of the molecules in 1/8CB films at the air-water interface is proposed.

scholarly journals Nanoparticle interaction with model lung surfactant monolayers

2009 ◽  
Vol 7 (suppl_1) ◽  
Author(s):  
Rakesh Kumar Harishchandra ◽  
Mohammed Saleem ◽  
Hans-Joachim Galla
Keyword(s):  
Surface Properties ◽  
Self Assembly ◽  
Current Knowledge ◽  
Surface Film ◽  
Lung Surfactant ◽  
Hydrophobic Surface ◽  
Surface Pattern ◽  
Lipid Monolayers ◽  
Water Interface ◽  
Air Water Interface

One of the most important functions of the lung surfactant monolayer is to form the first line of defence against inhaled aerosols such as nanoparticles (NPs), which remains largely unexplored. We report here, for the first time, the interaction of polyorganosiloxane NPs (AmorSil20: 22 nm in diameter) with lipid monolayers characteristic of alveolar surfactant. To enable a better understanding, the current knowledge about an established model surface film that mimics the surface properties of the lung is reviewed and major results originating from our group are summarized. The pure lipid components dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol have been used to study the biophysical behaviour of their monolayer films spread at the air–water interface in the presence of NPs. Film balance measurements combined with video-enhanced fluorescence microscopy have been used to investigate the formation of domain structures and the changes in the surface pattern induced by NPs. We are able to show that NPs are incorporated into lipid monolayers with a clear preference for defect structures at the fluid–crystalline interface leading to a considerable monolayer expansion and fluidization. NPs remain at the air–water interface probably by coating themselves with lipids in a self-assembly process, thereby exhibiting hydrophobic surface properties. We also show that the domain structure in lipid layers containing surfactant protein C, which is potentially responsible for the proper functioning of surfactant material, is considerably affected by NPs.

Effect of Chain Microstructure and Subphase pH on the Surface Properties and Aggregation Behavior of Amphiphilic Copolymers Based on Fluoroacrylates

2019 ◽  
Vol 816 ◽  
pp. 312-317
Author(s):  
Alexandra O. Grigoreva ◽  
E.Y. Polozov ◽  
S.D. Zaitsev
Keyword(s):  
Acrylic Acid ◽  
Surface Properties ◽  
Butyl Acrylate ◽  
Langmuir Monolayer ◽  
Aggregation Behavior ◽  
Reactivity Ratios ◽  
Water Interface ◽  
Amphiphilic Copolymers ◽  
Air Water Interface ◽  
Raft Agent

Copolymerization of 2,2,3,3,4,4,5,5-octafluoropentyl acrylate (OFPA) and acrylic acid (AA), OFPA and tert-butyl acrylate (t-BA) in presence ofdibenzylcarbonotrithioate (BTC) and polymeric RAFT-agents was studied, reactivity ratios were calculated. It was shown that type of RAFT-agent can influence on chain microstructure of obtained polymers. Aggregation behavior of obtained amphiphilic copolymers with different microstructures at the air/water interface was characterized by the Langmuir monolayer technique. The effect of the microstructureand subphase pH on the isotherm curves were shown.

Surface properties of semiamphiphilic dithiolium-TCNQ salts at the air-water interface

Langmuir ◽  
1993 ◽  
Vol 9 (2) ◽  
pp. 491-496 ◽  
Author(s):  
O. Fichet ◽  
D. Ducharme ◽  
V. Gionis ◽  
P. Delhaes ◽  
R. M. Leblanc
Keyword(s):  
Surface Properties ◽  
Water Interface ◽  
Air Water Interface

Fiber Optic Sensing of Fluorescent Emission from Compressed Cyanine-Dye-Impregnated Fatty Acid Monolayers at the Air/Water Interface

1988 ◽  
Vol 42 (4) ◽  
pp. 605-608 ◽  
Author(s):  
W. M. Reichert ◽  
C. J. Bruckner ◽  
Sui-Ren Wan
Keyword(s):  
Fatty Acid ◽  
Fiber Optics ◽  
Fiber Optic ◽  
Arachidic Acid ◽  
Cyanine Dye ◽  
Water Interface ◽  
Molecular Area ◽  
Molar Ratios ◽  
Langmuir Film Balance ◽  
Air Water Interface

Fluorescence was collected from cyanine-dye-impregnated arachidic acid monolayers at the air/water interface with the use of a fiber optics configuration and a Langmuir film balance. Fatty-acid-to-dye molar ratios in the monolayers ranged from 99:1 to 1:1. The monolayers were compressed in a step-wise manner, with sampling of cyanine fluorescence after each compression step. A drop in fluorescence intensity ranging from 20 to 80% was observed between the uncompressed and compressed monolayers. The observed fluorescence decrease appeared to be a function of barrier pressure rather than molecular area and dye concentration.

Bubble characterizations on hydrophobic surface using lattice Boltzmann simulation with large density ratios

2017 ◽  
Vol 27 (6) ◽  
pp. 1311-1322 ◽  
Author(s):  
Peng Du ◽  
Haibao Hu ◽  
Feng Ren ◽  
Dong Song
Keyword(s):  
Surface Properties ◽  
Lattice Boltzmann ◽  
Water Interface ◽  
Flow Conditions ◽  
Hydrophobic Surfaces ◽  
Content Type ◽  
Lattice Boltzmann Simulation ◽  
Air Water Interface ◽  
Density Ratios ◽  
Bubble Properties

Purpose The maintenance of the air–water interface is crucial for the drag reduction on hydrophobic surfaces. But the air bubbles become unstable and even washed away under high speed flow, causing the failure of surface hydrophobicity. Thereby, this paper aims to understand the relations between bubble behaviors and surface properties, flow conditions and to discover new methods to maintain the air–water interface. Design/methodology/approach Bubble properties on hydrophobic surfaces were characterized using single-component multiphase lattice Boltzmann simulation. Three equations of state (EOSs), including the Peng–Robinson, Carnahan–Starling and modified Kaplun–Meshalkin EOSs, were incorporated to achieve high density ratios. Findings Both the static and dynamic properties of bubbles on hydrophobic surfaces were investigated and analyzed under different flow conditions, solid–liquid interactions and surface topology. Originality/value By revealing the properties of bubbles on hydrophobic surfaces, the effects of flow conditions and surface properties were characterized. The maintenance method of air–water interface can be proposed according to the bubble properties in the study.

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