Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 353-367 |
| Seitenumfang | 15 |
| Fachzeitschrift | Clay minerals |
| Jahrgang | 50 |
| Ausgabenummer | 3 |
| Publikationsstatus | Veröffentlicht - Aug. 2015 |
Abstract
Organoclays are sorbent materials prepared from clays by exchanging inorganic with organic cations. Their properties depend on the loading and conformational structure of the organic cations, but little information is available about the surface structures of organoclays. In this work, X-ray photoelectron spectroscopy (XPS) and classical molecular dynamics (MD) simulations are combined to characterize the external interface of an organoclay prepared from hexadecylpyridinium (HDPy+) and bentonite. The XPS survey spectra show well the varying elemental composition of the surface with increasing amount of surfactant, showing a decreasing contribution of clay-derived elements with increasing organic coverage. The high-resolution C 1s XPS spectra depict sensitively the surface arrangement of the surfactant. In combination with MD simulations, the results implied a monolayer coating for low surfactant coverage and a disordered bilayer arrangement at high surfactant uptakes. Molecular dynamics simulations showed that for very high cation uptake a quasi-paraffin-like configuration is also possible. The combination of experimental and modelling methods yielded congruent information on the molecular-scale arrangement of organic cations at the organoclay surfaces and the controlling mechanisms.
ASJC Scopus Sachgebiete
- Erdkunde und Planetologie (insg.)
- Geochemie und Petrologie
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in: Clay minerals, Jahrgang 50, Nr. 3, 08.2015, S. 353-367.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Surface structure of organoclays as examined by X-ray photoelectron spectroscopy and molecular dynamics simulations
AU - Schampera, B.
AU - Solc, R.
AU - Woche, S. K.
AU - Mikutta, R.
AU - Dultz, S.
AU - Guggenberger, G.
AU - Tunega, D.
PY - 2015/8
Y1 - 2015/8
N2 - Organoclays are sorbent materials prepared from clays by exchanging inorganic with organic cations. Their properties depend on the loading and conformational structure of the organic cations, but little information is available about the surface structures of organoclays. In this work, X-ray photoelectron spectroscopy (XPS) and classical molecular dynamics (MD) simulations are combined to characterize the external interface of an organoclay prepared from hexadecylpyridinium (HDPy+) and bentonite. The XPS survey spectra show well the varying elemental composition of the surface with increasing amount of surfactant, showing a decreasing contribution of clay-derived elements with increasing organic coverage. The high-resolution C 1s XPS spectra depict sensitively the surface arrangement of the surfactant. In combination with MD simulations, the results implied a monolayer coating for low surfactant coverage and a disordered bilayer arrangement at high surfactant uptakes. Molecular dynamics simulations showed that for very high cation uptake a quasi-paraffin-like configuration is also possible. The combination of experimental and modelling methods yielded congruent information on the molecular-scale arrangement of organic cations at the organoclay surfaces and the controlling mechanisms.
AB - Organoclays are sorbent materials prepared from clays by exchanging inorganic with organic cations. Their properties depend on the loading and conformational structure of the organic cations, but little information is available about the surface structures of organoclays. In this work, X-ray photoelectron spectroscopy (XPS) and classical molecular dynamics (MD) simulations are combined to characterize the external interface of an organoclay prepared from hexadecylpyridinium (HDPy+) and bentonite. The XPS survey spectra show well the varying elemental composition of the surface with increasing amount of surfactant, showing a decreasing contribution of clay-derived elements with increasing organic coverage. The high-resolution C 1s XPS spectra depict sensitively the surface arrangement of the surfactant. In combination with MD simulations, the results implied a monolayer coating for low surfactant coverage and a disordered bilayer arrangement at high surfactant uptakes. Molecular dynamics simulations showed that for very high cation uptake a quasi-paraffin-like configuration is also possible. The combination of experimental and modelling methods yielded congruent information on the molecular-scale arrangement of organic cations at the organoclay surfaces and the controlling mechanisms.
KW - Molecular dynamics
KW - Organoclay
KW - Surface arrangement
KW - XPS
UR - http://www.scopus.com/inward/record.url?scp=84959568504&partnerID=8YFLogxK
U2 - 10.1180/claymin.2015.050.3.08
DO - 10.1180/claymin.2015.050.3.08
M3 - Article
AN - SCOPUS:84959568504
VL - 50
SP - 353
EP - 367
JO - Clay minerals
JF - Clay minerals
SN - 0009-8558
IS - 3
ER -