Surfactant film bending elasticity in microemulsions: Structure and droplet polydispersity

1993 ◽  
Vol 99 (6) ◽  
pp. 4759-4765 ◽  
Author(s):  
F. Sicoli ◽  
D. Langevin ◽  
L. T. Lee
Keyword(s):  
Bending Elasticity ◽  
Surfactant Film

Surfactant convertase action is not essential for surfactant film formation

1997 ◽  
Vol 273 (5) ◽  
pp. L907-L912 ◽  
Author(s):  
N. J. Gross ◽  
R. Veldhuizen ◽  
F. Possmayer ◽  
R. Dhand
Keyword(s):  
Surface Tension ◽  
Film Formation ◽  
Surface Film ◽  
Lower Surface ◽  
Diisopropyl Fluorophosphate ◽  
Surfactant Film ◽  
Surface Active ◽  
Lower Surface Tension ◽  
Surface Balance

A serine-active enzyme, “surfactant convertase,” is required for the conversion of surfactant from the tubular myelin (TM) form to the small vesicular (SV) form. This transformation involves at least two steps, the conversion of TM to a surface-active film at the air-fluid interface and the reorientation of the film into the surface-inactive SV form; we asked if convertase was required for the first of these steps. Rat and mouse TMs were pretreated with diisopropyl fluorophosphate (DFP) to inactivate endogenous convertase activity or with vehicle and then were analyzed for their ability to lower surface tension in vitro as an index of the conversion of TM to a surface film. DFP pretreatment did not alter the ability of TM preparations to lower surface tension, as assessed by pulsating bubble, and it did not affect the behavior of TM in a surface balance. In an experiment designed to test the ability of TM to feed a surface film to exhaustion, TMs that had been pretreated with DFP or vehicle performed similarly. These experiments show that convertase activity is not required for the conversion of TM to a monolayer and suggest, instead, that convertase acts at a post surface film stage.

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