Journal article
Cationic–anionic vesicle templating from fluorocarbon/fluorocarbon and hydrocarbon/fluorocarbon surfactants
Journal of colloid and interface science, Vol.338(1), pp.82-91
2009
DOI: 10.1016/j.jcis.2009.06.022
PMID: 19589537
Abstract
Catanionic vesicles with mixed hydrocarbon/fluorocarbon bilayers and full fluorocarbon bilayers used in synthesis of silica hollow spheres by templating.
Spontaneous catanionic vesicle formation is studied in systems comprising fluorinated surfactants, the cationic/anionic fluorinated surfactant system of 1,1,2,2-tetrahydroperfluorododecylpyridinium chloride (HFDPC)/sodium perfluorooctanoate (SPFO) and the analogous mixed hydrocarbon/fluorocarbon surfactant system of cetylpyridinium bromide (CPB)/SPFO. Aggregate formation is explored in the anionic-rich surfactant system (weight fraction of anionic surfactant,
γ
=
0.66–0.85) and a total surfactant concentration range of 0.1–2%
wt/wt for the fluorinated system and 0.4–2.2%
wt/wt for the mixed hydrocarbon/fluorocarbon system. Vesicle sizes range from approximately 40 to 200
nm for CPB/SPFO, as determined by negative staining transmission electron microscopy (TEM) and confirmed by dynamic light scattering. The primary vesicle diameter observed by TEM in the catanionic fluorinated/fluorinated surfactant system is smaller (20–50
nm). However, the relatively few larger vesicles (⩾100
nm) in the HFDPC/SPFO system dominate the dynamic light scattering measurements. Successful templating of silica hollow spheres is demonstrated in both HFDPC/SPFO and CPB/SPFO vesicle systems, using tetramethoxysilane (TMOS) as the silica precursor for the acid-catalyzed synthesis. The size of the resulting hollow silica particles is consistent with the templating of vesicles of the size range observed by TEM. Changes in zeta potential are used to monitor colloidal stability. At the conditions investigated (TMOS/surfactant weight ratios of 0.25–1.0, pH 3), the colloidal silica particles templated from fluorinated HFDPC/SPFO vesicles are more stable than the particles templated from the corresponding mixed fluorinated CPB/SPFO system. Further improvement of the stability of the colloidal particles is achieved in the CPB/SPFO systems by titrating the acid synthesis solution with base over the course of the particle synthesis.
Details
- Title: Subtitle
- Cationic–anionic vesicle templating from fluorocarbon/fluorocarbon and hydrocarbon/fluorocarbon surfactants
- Creators
- Vivian A Ojogun - Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506-0046, USAHans-Joachim Lehmler - Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242-5000, USABarbara L Knutson - Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506-0046, USA
- Resource Type
- Journal article
- Publication Details
- Journal of colloid and interface science, Vol.338(1), pp.82-91
- DOI
- 10.1016/j.jcis.2009.06.022
- PMID
- 19589537
- NLM abbreviation
- J Colloid Interface Sci
- ISSN
- 0021-9797
- eISSN
- 1095-7103
- Publisher
- Elsevier Inc
- Language
- English
- Date published
- 2009
- Academic Unit
- Occupational and Environmental Health; Iowa Neuroscience Institute
- Record Identifier
- 9984001091102771
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