The behaviour of mixed hydrocarbon-fluorocarbon surface active agents at the air-water interface

2007 ◽  
pp. 247-250 ◽  
Author(s):  
S. J. Burkitt ◽  
B. T. Ingram ◽  
R. H. Ottewill
Keyword(s):  
Water Interface ◽  
Surface Active Agents ◽  
Air Water Interface ◽  
Surface Active

Surface active properties at the air–water interface of β-casein and its fragments derived by plasmin proteolysis

1989 ◽  
Vol 56 (3) ◽  
pp. 487-494 ◽  
Author(s):  
Michael Wilson ◽  
Daniel M. Mulvihill ◽  
William J. Donnelly ◽  
Brian P. Gill
Keyword(s):  
Surface Tension ◽  
Water Interface ◽  
Active Protein ◽  
Drop Volume ◽  
V Protein ◽  
Proteose Peptone ◽  
Rate Determining Step ◽  
Surface Active Properties ◽  
Air Water Interface ◽  
Surface Active

Summaryβ-Casein, was enzymically modified by incubation with plasmin to yield γ-caseins and proteose peptones. Whole γ-, γ1-, γ2/γ3-caseins and whole proteose peptone (pp) were isolated from the hydrolysate mixture. The time dependence of surface tension at the air-water interface of solutions of β-casein and its plasmin derived fragments, at concentrations of 10−1 to 10−4% (w/v) protein, pH 7.0, was determined, at 25 °C, using a drop volume apparatus. The ranking of the proteins with respect to rate of reduction of surface tension, during the first rate determining step, at 10-2% (w/v) protein, was γ2/γ3 ≫ pp > whole γ- > γ1- > β-casein. The ranking of the proteins with respect to surface pressures attained after 40 min (π40) was concentration dependent. γ2/γ3-Caseins were found to be very surface active, decreasing surface tension rapidly and giving a high π40. γ1 Casein decreased surface activity somewhat faster than β-casein, but generally reached a lower π40. Whole γ-casein reflected the properties of both γ1 and γ2/γ3-caseins. Proteose peptone was found to decrease surface tension rapidly during the initial rate determining step; it gave a relatively high π40 at a bulk phase concentration of 10−3% (w/v) protein, but, it was the least surface active protein at 10−1 and 10−2% (w/v) protein.

Characterization of Surface-Active Biofilm Protein BslA in Self-Assembling Langmuir Monolayer at the Air–Water Interface

Langmuir ◽  
2017 ◽  
Vol 33 (30) ◽  
pp. 7548-7555 ◽  
Author(s):  
Wei Liu ◽  
Shanghao Li ◽  
Zhuguang Wang ◽  
Elsa C. Y. Yan ◽  
Roger M. Leblanc
Keyword(s):  
Langmuir Monolayer ◽  
Water Interface ◽  
Self Assembling ◽  
Air Water Interface ◽  
Surface Active

scholarly journals Ubiquinones have surface-active properties suited to transport electrons and protons across membranes

1980 ◽  
Vol 185 (3) ◽  
pp. 715-722 ◽  
Author(s):  
Peter J. Quinn ◽  
Manouchehre A. Esfahani
Keyword(s):  
Fatty Acyl ◽  
Side Chain ◽  
Water Interface ◽  
Collapse Pressure ◽  
Phospholipid Monolayer ◽  
Ideal Mixing ◽  
Surface Active Properties ◽  
Air Water Interface ◽  
Surface Active ◽  
Ubiquinone 10

Surface-active properties of ubiquinones and ubiquinols have been investigated by monomolecular-film techniques. Stable monolayers are formed at an air/water interface by the fully oxidized and reduced forms of the coenzyme; collapse pressures and hence stability of the films tend to increase with decreasing length of the isoprenoid side chain and films of the reduced coenzymes are more stable than those of their oxidized counterparts. Ubiquinone with a side chain of two isoprenoid units does not form stable monolayers at the air/water interface. Mixed monolayers of ubiquinol-10 or ubiquinone-10 with 1,2-dimyristoyl phosphatidylcholine, soya phosphatidylcholine and diphosphatidylglycerol do not exhibit ideal mixing characteristics. At surface pressures less than the collapse pressure of pure ubiquinone-10 monolayers (approx. 12mN·m−1) the isoprenoid chain is located substantially within the region occupied by the fatty acyl residues of the phospholipids. With increasing surface pressure the ubiquinones and their fully reduced equivalents are progressively squeezed out from between the phospholipid molecules until, at a pressure of about 35mN·m−1, the film has surface properties consistent with that of the pure phospholipid monolayer. This suggests that the ubiquinone(ol) forms a separate phase overlying the phospholipid monolayer. The implications of this energetically poised situation, where the quinone(ol) is just able to penetrate the phospholipid film, are considered in terms of the function of ubiquinone(ol) as electron and proton carriers of energy-transducing membranes.

Transport of surface-active organic materials from seawater to the air-water interface by an ascending current field

1992 ◽  
Vol 9 (1-3) ◽  
pp. 97-105 ◽  
Author(s):  
John W Brown ◽  
Richard A Skop ◽  
John Viechnicki ◽  
Ruo-Shan Tseng
Keyword(s):  
Organic Materials ◽  
Water Interface ◽  
Current Field ◽  
Air Water Interface ◽  
Surface Active

scholarly journals Interaction Energy Analysis of Monovalent Inorganic Anions in Bulk Water Versus Air/Water Interface

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6719
Author(s):  
John M. Herbert ◽  
Suranjan K. Paul
Keyword(s):  
Surface Activity ◽  
Mechanical Energy ◽  
Decomposition Analysis ◽  
Bulk Water ◽  
Active Species ◽  
Energy Decomposition Analysis ◽  
Water Interface ◽  
Surface Activities ◽  
Air Water Interface ◽  
Surface Active

Soft anions exhibit surface activity at the air/water interface that can be probed using surface-sensitive vibrational spectroscopy, but the structural implications of this surface activity remain a matter of debate. Here, we examine the nature of anion–water interactions at the air/water interface using a combination of molecular dynamics simulations and quantum-mechanical energy decomposition analysis based on symmetry-adapted perturbation theory. Results are presented for a set of monovalent anions, including Cl−, Br−, I−, CN−, OCN−, SCN−, NO2−, NO3−, and ClOn− (n=1,2,3,4), several of which are archetypal examples of surface-active species. In all cases, we find that average anion–water interaction energies are systematically larger in bulk water although the difference (with respect to the same quantity computed in the interfacial environment) is well within the magnitude of the instantaneous fluctuations. Specifically for the surface-active species Br−(aq), I−(aq), ClO4−(aq), and SCN−(aq), and also for ClO−(aq), the charge-transfer (CT) energy is found to be larger at the interface than it is in bulk water, by an amount that is greater than the standard deviation of the fluctuations. The Cl−(aq) ion has a slightly larger CT energy at the interface, but NO3−(aq) does not; these two species are borderline cases where consensus is lacking regarding their surface activity. However, CT stabilization amounts to <20% of the total induction energy for each of the ions considered here, and CT-free polarization energies are systematically larger in bulk water in all cases. As such, the role of these effects in the surface activity of soft anions remains unclear. This analysis complements our recent work suggesting that the short-range solvation structure around these ions is scarcely different at the air/water interface from what it is in bulk water. Together, these observations suggest that changes in first-shell hydration structure around soft anions cannot explain observed surface activities.

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