Unit:
Department of ChemistryLibrary of the School of Science
Author:
Kainourgiakis Emmanouil
Dissertation committee:
Δρ. Ιωάννης Σάμιος, Ομότιμος Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Δρ. Ανδρέας Κούτσελος, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Δρ. Ιωάννης Οικονόμου, Καθηγητής Χημικής Μηχανικής, Texas A&M University at Qatar
Δρ. Γεώργιος Σουλιώτης, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Δρ. Γεώργιος Παπαδογιαννάκης, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Δρ. Αριστοτέλης Παπακονδύλης, Αναπληρωτής Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Δρ. Απόστολος Καλέμος, Επίκουρος Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Original Title:
Μελέτη υδατικών και οργανικών διαλυμάτων επιφανειοδραστικών ουσιών μέσω στατιστικής μηχανικής θεωρίας και υπολογιστικών μεθόδων-προσομοιώσεων. Εφαρμογή στα μοριακά συστήματα του χλωριδίου του Ν,Ν,Ν-τριμεθυλοδεκανο-1-αμινίου σε υδατικό και οργανικό περιβάλλον.
Translated title:
Study of aquatic and organic solutions of surfactnats through statistical mehanical theory and computational methods-simulations. Application on the molecular systems of N,N,N-decyltrimethylammonium chloride in aquatic and organic environment.
Summary:
In the present Doctoral Thesis, we report on the micellization behavior of the cationic surfactant N,N,N-decyltrimethyl ammonium chloride in water, studied via an explicit-solvent, very long atomistic molecular dynamics simulation. We aim at systematically exploring the related properties of the surfactant solution, focusing at first on their accurate prediction via simulations long enough to allow their precise calculation based on phase space trajectories that fall within the “true thermodynamic equilibrium”. To accomplish this goal, explicit-solvent, atomistic molecular dynamics runs were performed attaining, for the first time, simulation time scales of ≈1.2 μs. According to the results obtained, these novel simulations led to a rigorous estimation and detailed analysis of the properties related to the aggregation process such as the average number of free monomers, the average size and shape of formed micelles, the critical micelle concentration of the solution, the temporal evolution of cluster size distribution and others. It turns out from the analysis of the principal moments of inertia of the micelles that their average shape is oblate ellipsoidal. Also, from the pair radial distribution functions the average cross-sectional structure of the micelles reveals a hydrophobic core composed of the surfactant tail groups, while their outer shell consists from the hydrophilic heads. Moreover, it is found that the chloride counterions form a Stern layer around the micelles and close to the hydrophilic heads, while water molecules were also identified very close to the micelles. The results obtained are in good agreement with quite recent experimental data (previously not available) but differ from those of previous atomistic simulations of similar systems, covering time scales between a few tens and hundreds of ns for the most recent of them.Our results clearly indicate that the required system equilibrium is achieved at about 800 ns and beyond. In addition we studied the encapsulation of n-tetradecene during the micellar aggregation, as well as the effect of its addition to the system on the aforementioned properties.
Finally, the adsorption of molecular hydrogen in the formed micelles was investigated, while specific results regarding its relative position from the unsaturated molecule’s double bond were extracted. Those results may provide a stepping stone for a further investigation of the hydrogenation reaction of alkenes in micellar solutions
Main subject category:
Science
Keywords:
Statistical Mechanics, Molecular Dynamics Simulation, Surfactants Micellization, Adsorption in Micelles
Number of references:
242
File:
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PhD_E_Kainourgiakis.pdf
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File access is restricted only to the intranet of UoA.
