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Molecular Structure and Dynamics of a Nonionic Surfactant (C12E5) in Lamellar Phase : 13C Solid State NMR and MD Simulations

Pigliapochi, Roberta LU (2012) KEMP37 20121
Department of Chemistry
Abstract
Popular Science Description
Surfactants are compounds broadly used in daily life products as cosmetics, soaps or detergents. A better understanding of the processes occurring at a molecular scale leads to an improvement of their applications. The following work presents a 13C NMR procedure that allows to study the dynamics of these systems: an important insight into the motional mechanisms is hence obtained thorugh common experimental analysis.
Abstract
The following work presents a theoretical model for evaluating the eective correlation time, e, in regards to surfactants in lamellar phase, by focusing on nuclear spin relaxation processes. The dynamics of the C-H bonds is studied through a specic form of the autocorrelation function, g( ), which undergoes a plateau region at intermediate time-scales equals to the square of the order parameter, S2 CH. Thus, the area between the curve and its plateau is dened to be equal to (1 - S2CH)e. The presented experimental scheme shows how to measure e through 13C Solid State NMR analysis, basing on the dependence of R1 and R1 rate constants on the spectral density j(w), Fourier Transform of the correlation function, at particoular frequencies. The... (More)
The following work presents a theoretical model for evaluating the eective correlation time, e, in regards to surfactants in lamellar phase, by focusing on nuclear spin relaxation processes. The dynamics of the C-H bonds is studied through a specic form of the autocorrelation function, g( ), which undergoes a plateau region at intermediate time-scales equals to the square of the order parameter, S2 CH. Thus, the area between the curve and its plateau is dened to be equal to (1 - S2CH)e. The presented experimental scheme shows how to measure e through 13C Solid State NMR analysis, basing on the dependence of R1 and R1 rate constants on the spectral density j(w), Fourier Transform of the correlation function, at particoular frequencies. The results are compared with measurements of the eective correlation time through MD simulations. Furthemore, regarding the latter method, a better insight into the structure of the lamellar phase system is shown. (Less)
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author
Pigliapochi, Roberta LU
supervisor
organization
course
KEMP37 20121
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Fysikalisk kemi
language
English
id
3132338
date added to LUP
2012-11-05 11:00:22
date last changed
2012-11-05 11:00:22
@misc{3132338,
  abstract     = {The following work presents a theoretical model for evaluating the eective correlation time, e, in regards to surfactants in lamellar phase, by focusing on nuclear spin relaxation processes. The dynamics of the C-H bonds is studied through a specic form of the autocorrelation function, g( ), which undergoes a plateau region at intermediate time-scales equals to the square of the order parameter, S2 CH. Thus, the area between the curve and its plateau is dened to be equal to (1 - S2CH)e. The presented experimental scheme shows how to measure e through 13C Solid State NMR analysis, basing on the dependence of R1 and R1 rate constants on the spectral density j(w), Fourier Transform of the correlation function, at particoular frequencies. The results are compared with measurements of the eective correlation time through MD simulations. Furthemore, regarding the latter method, a better insight into the structure of the lamellar phase system is shown.},
  author       = {Pigliapochi, Roberta},
  keyword      = {Fysikalisk kemi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Molecular Structure and Dynamics of a Nonionic Surfactant (C12E5) in Lamellar Phase : 13C Solid State NMR and MD Simulations},
  year         = {2012},
}