TY - JOUR
T1 - Microstructure determination of AOT + phenol organogels utilizing small-angle X-ray scattering and atomic force microscopy
AU - Simmons, B. A.
AU - Taylor, C. E.
AU - Landis, F. A.
AU - John, V. T.
AU - McPherson, G. L.
AU - Schwartz, D. K.
AU - Moore, R.
PY - 2001/10/9
Y1 - 2001/10/9
N2 - Dry reverse micelles of the anionic twin-tailed surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) dissolved in nonpolar solvents spontaneously form an organogel when p-chlorophenol is added in a 1:1 AOT: phenol molar ratio. The solvents used were benzene, toluene, m-xylene, 2,2,4-trimethylpentane (isooctane), decane, dodecane, tetradecane, hexadecane, and 2,6,10,14-tetramethylpentadecane (TMPD). The proposed microstructure of the gel is based on strands of stacked phenols linked to AOT through hydrogen bonding. Small-angle X-ray scattering (SAXS) spectra of the organogels suggest a characteristic length scale for these phenol - AOT strands that is independent of concentration but dependent on the chemical nature of the nonpolar solvent used. Correlation lengths determined from the SAXS spectra indicate that the strands self-assemble into fibers. Direct visualization of the gel in its native state is accomplished by using tapping mode atomic force microscopy (AFM). It is shown that these organogels consist of fiber bundle assemblies. The SAXS and AFM data reinforce the theory of a molecular architecture consisting of three length scales - AOT/phenolic strands (ca. 2 nm in diameter) that self-assemble into fibers (ca. 10 nm in diameter), which then aggregate into fiber bundles (ca. 20 - 100 nm in diameter) and form the organogel.
AB - Dry reverse micelles of the anionic twin-tailed surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) dissolved in nonpolar solvents spontaneously form an organogel when p-chlorophenol is added in a 1:1 AOT: phenol molar ratio. The solvents used were benzene, toluene, m-xylene, 2,2,4-trimethylpentane (isooctane), decane, dodecane, tetradecane, hexadecane, and 2,6,10,14-tetramethylpentadecane (TMPD). The proposed microstructure of the gel is based on strands of stacked phenols linked to AOT through hydrogen bonding. Small-angle X-ray scattering (SAXS) spectra of the organogels suggest a characteristic length scale for these phenol - AOT strands that is independent of concentration but dependent on the chemical nature of the nonpolar solvent used. Correlation lengths determined from the SAXS spectra indicate that the strands self-assemble into fibers. Direct visualization of the gel in its native state is accomplished by using tapping mode atomic force microscopy (AFM). It is shown that these organogels consist of fiber bundle assemblies. The SAXS and AFM data reinforce the theory of a molecular architecture consisting of three length scales - AOT/phenolic strands (ca. 2 nm in diameter) that self-assemble into fibers (ca. 10 nm in diameter), which then aggregate into fiber bundles (ca. 20 - 100 nm in diameter) and form the organogel.
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U2 - 10.1021/ja0037926
DO - 10.1021/ja0037926
M3 - Article
C2 - 11456891
AN - SCOPUS:0034811666
SN - 0002-7863
VL - 123
SP - 2414
EP - 2421
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 10
ER -