Cationic-anionic vesicle templating from fluorocarbon/fluorocarbon and hydrocarbon/fluorocarbon surfactants
Vivian A Ojogun1, Hans-Joachim Lehmler, Barbara L Knutson
1Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506-0046, USA.
Journal of Colloid and Interface Science
|July 11, 2009
Summary
This study explores catanionic vesicle formation using fluorinated and mixed surfactants. Fluorinated surfactant systems yield smaller vesicles and more stable silica nanoparticles compared to mixed systems.
Area of Science:
- Colloid and Surface Science
- Materials Chemistry
- Nanotechnology
Background:
- Catanionic vesicles are self-assembled structures formed by oppositely charged surfactants.
- Fluorinated surfactants offer unique properties due to their low surface energy and high chemical stability.
- Understanding vesicle formation is crucial for applications in templating and encapsulation.
Purpose of the Study:
- To investigate spontaneous catanionic vesicle formation in fluorinated and mixed hydrocarbon/fluorocarbon surfactant systems.
- To compare the vesicle characteristics and templating capabilities of these two systems.
- To assess the colloidal stability of silica nanoparticles templated by these vesicles.
Main Methods:
- Utilized 1,1,2,2-tetrahydroperfluorododecylpyridinium chloride (HFDPC)/sodium perfluorooctanoate (SPFO) and cetylpyridinium bromide (CPB)/SPFO surfactant systems.
- Employed negative staining transmission electron microscopy (TEM) and dynamic light scattering (DLS) to determine vesicle size.
- Synthesized silica hollow spheres using tetramethoxysilane (TMOS) as a precursor, with zeta potential measurements for stability analysis.
Main Results:
- Vesicle sizes ranged from 40-200 nm for CPB/SPFO and 20-50 nm (primary) for HFDPC/SPFO.
- TEM and DLS revealed different size distributions, with larger vesicles dominating DLS in the HFDPC/SPFO system.
- Silica hollow spheres were successfully templated, with particles from HFDPC/SPFO vesicles showing greater colloidal stability at pH 3.
Conclusions:
- Fluorinated catanionic vesicle systems, particularly HFDPC/SPFO, form smaller primary vesicles compared to mixed systems.
- The HFDPC/SPFO system demonstrates superior performance in templating stable silica hollow spheres.
- Zeta potential measurements confirm enhanced colloidal stability for silica particles derived from fluorinated surfactant vesicles, with potential for further improvement through controlled synthesis conditions.
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