Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Molecular Arrangement, Electronic Structure and Transport Properties in Surfactant Gel- and Related Systems Studied by Soft X-ray and Dielectric Spectroscopy
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis concerns studies of aqueous soft matter systems, especially surfactant micelle systems.

The aim has been to study the molecular arrangement and electronic structure of the constituents of, as well as transport properties in such a system. The molecular arrangement and electronic structure has been studied by means of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray spectroscopy (RIXS). The transport properties have been investigated by low-frequency dielectric spectroscopy (LFDS) and small angle X-ray scattering (SAXS) as well as a theoretical modelling. The latter was based on Fick’s laws of the release from binary surfactant system and was validated by experiments.

The RIXS and XAS measurements show the electronic structure in bulk water and the influence of the chemical surrounding of the water molecule in bulk water and of the water molecules confined in a micelle lattice. The spectra are highly dependent on the molecular arrangement in such systems. For glycine and sodium polyacrylate RIXS and XAS spectra show features which are unique for carboxyl and carboxylate groups and such measurements can thus be used for fingerprinting.

The LFDS and SAXS measurements show a strong correlation between structure in a surfactant/poly-ion system and apparent mobility of surfactants. This conclusion is in line with earlier observations.

By the theoretical modelling a predictive model for the surfactant release from a binary surfactant micelle system has been obtained and the importance of different factors for surfactant release has been further clarified.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. , 77 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1060
Keyword [en]
surfactants, surfactant/poly-ion gel, water, confined water, XAS, RIXS, dielectric spectroscopy, SAXS, pKa, transport, Fick’s law
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
URN: urn:nbn:se:uu:diva-205072ISBN: 978-91-554-8721-8 (print)OAI: oai:DiVA.org:uu-205072DiVA: diva2:640482
Public defence
2013-09-27, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30 (Swedish)
Opponent
Supervisors
Available from: 2013-09-04 Created: 2013-08-13 Last updated: 2014-01-08
List of papers
1. Angular anisotropy in resonant inelastic soft X-ray scattering of liquid water
Open this publication in new window or tab >>Angular anisotropy in resonant inelastic soft X-ray scattering of liquid water
Show others...
2009 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, no 13, 132203- p.Article in journal (Refereed) Published
Abstract [en]

Resonantly excited soft x-ray emission spectra of liquid water have been measured at two different angles relative to the polarization direction of the exciting radiation. The results demonstrate that the emission is much more isotropic than expected for the free water   molecule but that the trends in the remaining anisotropy qualitatively agree. It is found that the two sharp oxygen peaks at high emission energy correspond to states of different symmetry.

 

Keyword
liquid structure, resonant states, water, X-ray emission spectra, X-ray scattering
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-98012 (URN)10.1103/PhysRevB.79.132203 (DOI)000265942800013 ()
Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2017-12-14Bibliographically approved
2. Electronic structure of water molecules confined in a micelle lattice
Open this publication in new window or tab >>Electronic structure of water molecules confined in a micelle lattice
Show others...
2009 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 113, no 24, 8201-8205 p.Article in journal (Refereed) Published
Abstract [en]

Oxygen K absorption and emission spectra of water molecules confined in dodecyltrimethyl ammonium chloride micelle structures are presented. The local electronic structure of the water molecules is found to be dramatically different from the electronic structure of water molecules in the gas-phase as well as in liquid water. Hybridization with states of the ions in the surrounding ions is directly observed, and evidence for stabilization of the water molecules relative to molecules in bulk water is found.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-109461 (URN)10.1021/jp902058w (DOI)000266930200001 ()19473020 (PubMedID)
Available from: 2009-10-15 Created: 2009-10-15 Last updated: 2017-12-12Bibliographically approved
3. Local Electronic Structure of Functional Groups in Glycine As Anion, Zwitterion, and Cation in Aqueous Solution
Open this publication in new window or tab >>Local Electronic Structure of Functional Groups in Glycine As Anion, Zwitterion, and Cation in Aqueous Solution
Show others...
2009 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 113, no 49, 16002-16006 p.Article in journal (Refereed) Published
Abstract [en]

Nitrogen and oxygen K emission spectra of glycine in the form of  anions, zwitterions, and cations in aqueous solution are presented. It  is shown that protonation has a dramatic influence on the local   electronic structure and that the functional groups give a distinct  spectral fingerprint.

 

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-121091 (URN)10.1021/jp905998x (DOI)000272083000012 ()
Available from: 2010-03-18 Created: 2010-03-18 Last updated: 2017-12-12Bibliographically approved
4. Ion mobility and gel complex structure in dodecyl trimethylammonium/polyacrylate gel complexes
Open this publication in new window or tab >>Ion mobility and gel complex structure in dodecyl trimethylammonium/polyacrylate gel complexes
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In the present study dielectric spectroscopy and small angle x-ray scattering were employed to evaluate temperature dependent ionic mobility and structural features in a dodecyltrimethylammonium/polyacrylate gel complex. A gradually transition of  the gel complex from a structure exclusively consisting of discrete micelles arranged on a hexagonal close-packed lattice at 25 °C to a structure mainly consisting of a hexagonal phase of long rod-like micelles at ~ 65 °C was revealed. As well it was found that the mobility of the dodecyltrimethylammonium surfactant ions increased with an increasing fraction of hexagonal phase domains, something which was most likely due to a “residence time-hopping distance” mechanism of monomer ions moving between the micelles. The present findings should be useful for the understanding of the gel structure influence on the mechanisms for surfactant transport and shell formation in surfactant polyion gel complexes.

Keyword
Dielectric Spectroscopy, SAXS, Dodecyltrimethyl ammonium ion, polyacrylate ion, surfactant-poly ion complexes, mobility
National Category
Natural Sciences
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-205020 (URN)
Available from: 2013-08-13 Created: 2013-08-13 Last updated: 2014-01-08
5. Determining the static dielectric permittivity of ion conducting materials
Open this publication in new window or tab >>Determining the static dielectric permittivity of ion conducting materials
2008 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, no 9, 092901-1 p.Article in journal (Refereed) Published
Abstract [en]

A method is derived for the determination of the static dielectric permittivity of ion conducting materials when this parameter is obscured by electrode polarization in as-recorded low frequency dielectric spectra. The method requires permittivity measurements at two different electrode separations, and is applicable when the electric fields created by charge separation near the electrode surfaces do not induce nonlinear effects in the frequency region where electrode polarization begins to affect the dielectric response. The performance of the method is illustrated by the analysis of an ion conducting cellulose gel biosynthesized by the Acetobacter. xylinum bacterium. The method opens up possibilities to obtain more detailed information about dynamic processes in ion conducting materials from dielectric spectroscopy.

National Category
Other Engineering and Technologies
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-17822 (URN)10.1063/1.2977861 (DOI)000258975800043 ()
Available from: 2008-09-03 Created: 2008-09-03 Last updated: 2017-12-08Bibliographically approved
6. Implications of regular solution theory on the release mechanism of catanionic mixtures from gels
Open this publication in new window or tab >>Implications of regular solution theory on the release mechanism of catanionic mixtures from gels
Show others...
2009 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 71, no 2, 214-225 p.Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to apply the regular solution theory of mixed  micelles to gain new insights on the drug release mechanism, when using   catanionic mixtures as a method of obtaining prolonged release from   gels. Synergistic effects were investigated at equilibrium and   quantified in terms of regular solution theory interaction parameters.  The drug release from catanionic aggregates was studied both in a polymer free environment, using dialysis membranes, and in gels, using  a modified LISP paddle method. The drug release kinetics was modelled   theoretically by combining the regular solution theory with Fick's   diffusion laws assuming a contribution to the transport only from monomeric species (stationary aggregates). The theoretical predictions were found to be in reasonably good agreement with experiments. An analysis of the calculated distribution of species between aggregated and monomeric states was shown to provide further insights into the release mechanism.

Keyword
Vesicle, Micelle, Catanionic, Regular solution theory, Diffusion
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-96417 (URN)10.1016/j.colsurfb.2009.02.008 (DOI)000266897900008 ()19286357 (PubMedID)
Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2017-12-14Bibliographically approved
7. The Release of Catanionic Mixtures Embedded in Gels: An Approximate Analytical Analysis
Open this publication in new window or tab >>The Release of Catanionic Mixtures Embedded in Gels: An Approximate Analytical Analysis
2011 (English)In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 57, no 6, 1402-1408 p.Article in journal (Refereed) Published
Abstract [en]

We present an approximate analytical analysis of the release of catanionic mixtures from gels. The starting points are the monomer-mixed micelle equilibrium, described by using regular solution theory, and the one-dimensional diffusion equation. Focusing on a half-infinite planar system, we first point out an exact reduction of the problem to a system of ordinary differential equations. By using the pseudo-steady-state approximation and the integral-balance method, we then derive a single nonlinear equation for the mole fraction of drug in micelles at the extraction front. This equation may be readily solved numerically (or graphically), and once the solution is found, all quantities of interest may be determined in closed form. Comparisons with numerical solutions of the fully nonlinear problem indicate that the errors resulting from the approximations typically do not exceed 10%.

Keyword
controlled drug delivery, release, drug release, mathematical modeling, diffusion, catanionic mixtures
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-154684 (URN)10.1002/aic.12368 (DOI)000290616500004 ()
Available from: 2011-06-09 Created: 2011-06-09 Last updated: 2017-12-11Bibliographically approved

Open Access in DiVA

fulltext(5376 kB)874 downloads
File information
File name FULLTEXT01.pdfFile size 5376 kBChecksum SHA-512
c30fd9c4e10cd11514bd2aec9d9a198c85e0c9a0f051b65882432ca7bdb676589206ce90e3ef41dd2e30c192a12224e421f59aa2fedc46eeaae1cebea4116a6d
Type fulltextMimetype application/pdf