Informace o publikaci

Nature of CTAB/Water/Chloroform Reverse Micelles at Above- and Subzero Temperatures Studied by NMR and Molecular Dynamics Simulations

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KLÍČOVÁ Ľubica MUCHOVÁ Eva ŠEBEJ Peter SLAVÍČEK Petr KLÁN Petr

Druh Článek v odborném periodiku
Časopis / Zdroj Langmuir
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
www http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.5b01776
Doi http://dx.doi.org/10.1021/acs.langmuir.5b01776
Obor Organická chemie
Klíčová slova reverse micelles; ice; MD simulations
Popis The nature and stability of cetyltrimethylammonium bromide (CTAB) reverse micelles in chloroform formed above the critical micellar concentration at above- and subzero temperatures were examined by NMR and molecular dynamics simulations. The experiments showed that the supercooled micellar water pool becomes unstable upon cooling to relatively high temperatures (253 K), and smaller micelles are formed. Upon freezing at lower temperatures (233 K), micelles become completely frozen and remain intact in the solution. With an average hydrodynamic radius of approximately 1.3 nm, we estimate that the water pool contains approximately 50 water molecules, which is well below the onset of ice crystal formation. To support the experimental results, molecular dynamics simulations were used to model the structure of CTAB/water/chloroform reverse micelles of different sizes. The MD simulations show that the reverse micelles contain a water pool with bromide anions residing on its surface and their shape is nonspherical, especially in the case of larger water pools. Upon fast freezing, the mobility of the water molecules is suppressed, and the pool becomes more spherical.
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