Time-resolved measurement of equilibrium surface tensions at the electrified mercury-aqueous sodium fluoride interphase by the method of Wilhelmy

Langmuir ◽  
1991 ◽  
Vol 7 (5) ◽  
pp. 1000-1004 ◽  
Author(s):  
Donald D. Montgomery ◽  
Fred C. Anson
Keyword(s):  
Sodium Fluoride ◽  
Surface Tensions ◽  
Time Resolved ◽  
Aqueous Sodium ◽  
Equilibrium Surface

Preparation and Properties of Amide Surfactants

2012 ◽  
Vol 550-553 ◽  
pp. 99-102
Author(s):  
Bao Cai Xu ◽  
Gui Ju Zhang ◽  
Yun Xia Li ◽  
Lu Cui
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Aqueous Solutions ◽  
Surface Activity ◽  
Surface Tensions ◽  
Equilibrium Surface ◽  
Minimum Surface Tension ◽  
Dilute Aqueous Solutions ◽  
Lipophilic Groups ◽  
Long Chain

Amide surfactants have modified structures with lipophilic groups connecting hydrophilic groups through amido bond. The preparation of three families of amide surfactants including long chain N-acyl sarcosinates, amidopropyl dimethyl hydroxypropyl sulfobetaines and lauryl amidopropyl trimethyl ammoniums were discussed. The study of the surface activity of these compounds by measuring the equilibrium surface tensions of their dilute aqueous solutions were described. The minimum surface tension and the critical micelle concentration values of these compounds are given.

Dynamic surface tension of xylem sap lipids

2020 ◽  
Vol 40 (4) ◽  
pp. 433-444 ◽  
Author(s):  
Jinlong Yang ◽  
Joseph M Michaud ◽  
Steven Jansen ◽  
H Jochen Schenk ◽  
Yi Y Zuo
Keyword(s):  
Surface Tension ◽  
Surface Area ◽  
Xylem Sap ◽  
Dynamic Surface Tension ◽  
Liquid Interfaces ◽  
Surface Tensions ◽  
Local Surface ◽  
Dynamic Surface ◽  
Equilibrium Surface ◽  
Pit Membrane

Abstract The surface tension of xylem sap has been traditionally assumed to be close to that of the pure water because decreasing surface tension is thought to increase vulnerability to air seeding and embolism. However, xylem sap contains insoluble lipid-based surfactants, which also coat vessel and pit membrane surfaces, where gas bubbles can enter xylem under negative pressure in the process known as air seeding. Because of the insolubility of amphiphilic lipids, the surface tension influencing air seeding in pit pores is not the equilibrium surface tension of extracted bulk sap but the local surface tension at gas–liquid interfaces, which depends dynamically on the local concentration of lipids per surface area. To estimate the dynamic surface tension in lipid layers that line surfaces in the xylem apoplast, we studied the time-dependent and surface area-regulated surface tensions of apoplastic lipids extracted from xylem sap of four woody angiosperm plants using constrained drop surfactometry. Xylem lipids were found to demonstrate potent surface activity, with surface tensions reaching an equilibrium at ~25 mN m-1 and varying between a minimum of 19 mN m-1 and a maximum of 68 mN m-1 when changing the surface area between 50 and 160% around the equilibrium surface area. It is concluded that xylem lipid films in natural conditions most likely range from nonequilibrium metastable conditions of a supersaturated compression state to an undersaturated expansion state, depending on the local surface areas of gas–liquid interfaces. Together with findings that maximum pore constrictions in angiosperm pit membranes are much smaller than previously assumed, low dynamic surface tension in xylem turns out to be entirely compatible with the cohesion–tension and air-seeding theories, as well as with the existence of lipid-coated nanobubbles in xylem sap, and with the range of vulnerabilities to embolism observed in plants.

Dynamic and equilibrium surface tensions of surfactin aqueous solutions

2004 ◽  
Vol 7 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Hary Razafindralambo ◽  
Philippe Thonart ◽  
Michel Paquox
Keyword(s):  
Aqueous Solutions ◽  
Surface Tensions ◽  
Equilibrium Surface
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