Effect of bromide on the interfacial structure of aqueous tetrabutylammonium iodide: Photoelectron spectroscopy and molecular dynamics simulations

2005 ◽  
Vol 410 (4-6) ◽  
pp. 222-227 ◽  
Author(s):  
Bernd Winter ◽  
Ramona Weber ◽  
Ingolf V. Hertel ◽  
Manfred Faubel ◽  
Luboš Vrbka ◽  
...  
2016 ◽  
Vol 144 (15) ◽  
pp. 154704 ◽  
Author(s):  
Giorgia Olivieri ◽  
Krista M. Parry ◽  
Cedric J. Powell ◽  
Douglas J. Tobias ◽  
Matthew A. Brown

Clay Minerals ◽  
2015 ◽  
Vol 50 (3) ◽  
pp. 353-367 ◽  
Author(s):  
B. Schampera ◽  
R. Solc ◽  
S.K. Woche ◽  
R. Mikutta ◽  
S. Dultz ◽  
...  

AbstractOrganoclays 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.


2014 ◽  
Vol 16 (42) ◽  
pp. 23329-23339 ◽  
Author(s):  
Yong-Lei Wang ◽  
Aatto Laaksonen

Atomistic molecular dynamics simulations have been performed to study microscopic ionic structures and orientational preferences of absorbed [BMIM] cations and four paired anions ([BF4], [PF6], [TFO] and [TF2N]) on quartz surfaces.


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