NMR Diffusion Studies of Association in Surfactant Systems Inclusion Complexes, Micellar Solutions and Microemulsions
(2008)- Abstract
- The aim of this thesis has been to investigate self-diffusion behavior of host-guest complex,
microemulsion and polymer solution. Pulsed Field Gradient NMR (PFG-NMR) was shown to
provide detailed molecular information in all system studied. The general strategy was to measyre
the diffusivities of the species and from there get molecular insight into the aggregation and
dynamics of the system.
Guest host interaction has been studied between β-cyclodextrin (β-CD) and different
cationic surfactant. The equilibrium constant (K11) increases as a function of the number of CH2
groups in the surfactant chain. It could be concluded that the cavity of β-CD could incorporate... (More) - The aim of this thesis has been to investigate self-diffusion behavior of host-guest complex,
microemulsion and polymer solution. Pulsed Field Gradient NMR (PFG-NMR) was shown to
provide detailed molecular information in all system studied. The general strategy was to measyre
the diffusivities of the species and from there get molecular insight into the aggregation and
dynamics of the system.
Guest host interaction has been studied between β-cyclodextrin (β-CD) and different
cationic surfactant. The equilibrium constant (K11) increases as a function of the number of CH2
groups in the surfactant chain. It could be concluded that the cavity of β-CD could incorporate
approximately 10-12 CH2 groups and that it is the hydrophobic interaction that mainly is
responsible for the inclusion complex formed. The interaction between the gemini surfactant and
β-CD formed a 2:1 (CD:gemini) complex in a two step mechanism with the first association
constant higher than the second one (K2:1), but both relatively small in comparison with the
analogue singled tailed surfactant. The values of the K11 and K21 increased with gemini spacer
length which indicate that the available space on the gemini molecule is important. The second
association constant shows no cooperatively and its magnitude are discussed in terms of steric
constrains. Bolaform surfactant complexation was investigated with both β-CD and α-CD with
Isothermal Titration Calorimetry (ITC). The K11, enthalpy and entropy of formation were
obtained. From ITC a molecular interpretation is made explaining the enthalpy and entropy
difference between α- and β-CD.
In a second study diblock copolymers of the type methoxy poly(ethylene oxide)-
poly(alkylene oxide) were incorporated into the nonionic bicontinuous microemulsion at 298 K.
An enhancement of the microemulsion in solubilising water and oil were observed with a
boosting factor of 9. The self-diffusion coefficients of the components in the system were
measured and provided molecular information on how the microstructure of the bicontinuous
microemulsion changed upon addition of the polymers.
The diffusion study concerning the aqueous solution of the synthetic polymers, PEO-
PPO-PEO, is focused towards analyzing the PFG-NMR decay correctly. The polydispersity has
consequences on the polymer self-assembly, which were highlighted, modeled and discussed
based on PFG-NMR data. The main conclusion is that the curved NMR decay as obtained for
self-assembly can be explained with a multi-component ideal solution. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1040142
- author
- Nilsson, Markus LU
- supervisor
- opponent
-
- Dr. prof. Smidth, Claudia Smidth, Department of Chemistry, Faculty of Science, university of Paderbon, Germany
- organization
- publishing date
- 2008
- type
- Thesis
- publication status
- published
- subject
- keywords
- host-guest complexation, gemini surfactant, cyclodextrin, bolaform surfactant, self-diffusion NMR, pluronic, bicontinuous microemulsion, polydispersity, boosting effect
- pages
- 178 pages
- publisher
- Lund University (Media-Tryck)
- defense location
- Chemical Center room B
- defense date
- 2008-03-28 10:30:00
- language
- English
- LU publication?
- yes
- additional info
- For erreat or disscussion cosidering the content in the thesis contact Markus Nilsson. Phone number: 0730671403
- id
- c16d072f-9888-4a23-9922-8ed1ce81b7de (old id 1040142)
- date added to LUP
- 2016-04-04 11:25:37
- date last changed
- 2018-11-21 21:04:46
@phdthesis{c16d072f-9888-4a23-9922-8ed1ce81b7de, abstract = {{The aim of this thesis has been to investigate self-diffusion behavior of host-guest complex, <br/><br> microemulsion and polymer solution. Pulsed Field Gradient NMR (PFG-NMR) was shown to <br/><br> provide detailed molecular information in all system studied. The general strategy was to measyre <br/><br> the diffusivities of the species and from there get molecular insight into the aggregation and <br/><br> dynamics of the system. <br/><br> Guest host interaction has been studied between β-cyclodextrin (β-CD) and different <br/><br> cationic surfactant. The equilibrium constant (K11) increases as a function of the number of CH2 <br/><br> groups in the surfactant chain. It could be concluded that the cavity of β-CD could incorporate <br/><br> approximately 10-12 CH2 groups and that it is the hydrophobic interaction that mainly is <br/><br> responsible for the inclusion complex formed. The interaction between the gemini surfactant and <br/><br> β-CD formed a 2:1 (CD:gemini) complex in a two step mechanism with the first association <br/><br> constant higher than the second one (K2:1), but both relatively small in comparison with the <br/><br> analogue singled tailed surfactant. The values of the K11 and K21 increased with gemini spacer <br/><br> length which indicate that the available space on the gemini molecule is important. The second <br/><br> association constant shows no cooperatively and its magnitude are discussed in terms of steric <br/><br> constrains. Bolaform surfactant complexation was investigated with both β-CD and α-CD with <br/><br> Isothermal Titration Calorimetry (ITC). The K11, enthalpy and entropy of formation were <br/><br> obtained. From ITC a molecular interpretation is made explaining the enthalpy and entropy <br/><br> difference between α- and β-CD. <br/><br> In a second study diblock copolymers of the type methoxy poly(ethylene oxide)- <br/><br> poly(alkylene oxide) were incorporated into the nonionic bicontinuous microemulsion at 298 K. <br/><br> An enhancement of the microemulsion in solubilising water and oil were observed with a <br/><br> boosting factor of 9. The self-diffusion coefficients of the components in the system were <br/><br> measured and provided molecular information on how the microstructure of the bicontinuous <br/><br> microemulsion changed upon addition of the polymers. <br/><br> The diffusion study concerning the aqueous solution of the synthetic polymers, PEO- <br/><br> PPO-PEO, is focused towards analyzing the PFG-NMR decay correctly. The polydispersity has <br/><br> consequences on the polymer self-assembly, which were highlighted, modeled and discussed <br/><br> based on PFG-NMR data. The main conclusion is that the curved NMR decay as obtained for <br/><br> self-assembly can be explained with a multi-component ideal solution.}}, author = {{Nilsson, Markus}}, keywords = {{host-guest complexation; gemini surfactant; cyclodextrin; bolaform surfactant; self-diffusion NMR; pluronic; bicontinuous microemulsion; polydispersity; boosting effect}}, language = {{eng}}, publisher = {{Lund University (Media-Tryck)}}, school = {{Lund University}}, title = {{NMR Diffusion Studies of Association in Surfactant Systems Inclusion Complexes, Micellar Solutions and Microemulsions}}, url = {{https://lup.lub.lu.se/search/files/5771173/1040267.pdf}}, year = {{2008}}, }