ISSN:
1435-1536
Keywords:
Microemulsions
;
film bending elasticity
;
cationic surfactants
;
interfacial tension
;
SANS
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Films, consisting ofn-alkyldodecyldimethylammonium bromide surfactants (n=12, 14, 16 or 18) in Winsor II microemulsions have been studied using small-angle neutron scattering (SANS) and surface light scattering (SLS). The combined information obtained from these experiments allows the elastic moduli (2K + Kbar) to be obtained (K is the normal andKbar the Gaussian modulus). The values of (2K + Kbar) increased in the range 1.0–2.5 kB T with either the surfactant chain length and/or concentration of added NaBr electrolyte. For salt-free systems a scaling relationship was observed with film thicknesst, (2K + Kbar) ∼ t2.3. Using the approach of Mitchell and Ninham (Langmuir, 1989, 5, 1121), the separate electrostatic (2K + Kbar)elec and surfactant contributions (2K + Kbar) surf have been estimated. This work is the first systematic study of rigidities for dichain cationic surfactants, and shows that the film bending elasticity model is a good description of these microemulsions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01188975
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