Abstract
The aim of this study was to analyse physico-chemical properties of some complex liquids using the Poisson-Boltzmann (PB) cell model; to extend the theory to cover bilayer systems with complex global geometry; finally to apply this new extended model to such bilayer systems.
The PB cell model provides a practical tool to examine counterion association and phase behaviour for structures of simple geometries; cylindrical and spherical. The model applies to self-assembled aggregates of ionic surfactants as well as to a polyelectrolyte system.
The framework of the PB cell model provides a consistent route to derive the electrostatic contribution to Helfrich's bending energy at finite salt- and surfactant concentrations. The bending energy concept, with the extension of a variable electrostatic contribution to the bending rigidity, the saddle splay modulus, and the product (bending rigidity)*Ho (where Ho is the spontaneous mean curvature) was adopted for the description of the fluid mono- and bilayer phases, bicontinous microemulsion and L3 (sponge), respectively.
This formalism successfully describes many features of a ionic microemulsion system and the inclusion of both salt and surfactant concentration dependence was necessary for this purpose.
The same formalism provided the basis for a model description of the ternary system AerosolOT/NaCl/Water. A theoretical phase diagram, containing the L3 phase in competition with the lamellar phase and dilute solution, was calculated. The calculations captured the features typical for L3: narrowness in the one phase region and the characteristic sequence of phase transitions.
The PB cell model provides a practical tool to examine counterion association and phase behaviour for structures of simple geometries; cylindrical and spherical. The model applies to self-assembled aggregates of ionic surfactants as well as to a polyelectrolyte system.
The framework of the PB cell model provides a consistent route to derive the electrostatic contribution to Helfrich's bending energy at finite salt- and surfactant concentrations. The bending energy concept, with the extension of a variable electrostatic contribution to the bending rigidity, the saddle splay modulus, and the product (bending rigidity)*Ho (where Ho is the spontaneous mean curvature) was adopted for the description of the fluid mono- and bilayer phases, bicontinous microemulsion and L3 (sponge), respectively.
This formalism successfully describes many features of a ionic microemulsion system and the inclusion of both salt and surfactant concentration dependence was necessary for this purpose.
The same formalism provided the basis for a model description of the ternary system AerosolOT/NaCl/Water. A theoretical phase diagram, containing the L3 phase in competition with the lamellar phase and dilute solution, was calculated. The calculations captured the features typical for L3: narrowness in the one phase region and the characteristic sequence of phase transitions.
| Original language | English |
|---|---|
| Qualification | Doctor |
| Awarding Institution |
|
| Supervisors/Advisors |
|
| Award date | 1998 Feb 7 |
| Publisher | |
| ISBN (Print) | 91-628-2839-8 |
| Publication status | Published - 1998 |
Bibliographical note
Defence detailsDate: 1998-02-07
Time: 10:15
Place: Room E, Center for Chemistry and Chemical Engineering, Lund University
External reviewer(s)
Name: Evans, Fennell
Title: Prof
Affiliation: Dept. of Chemical Engineering and Materials Science, University of Minnesota
---
Subject classification (UKÄ)
- Physical Chemistry (including Surface- and Colloid Chemistry)
Free keywords
- AOT
- AerosolOT
- ionic surfactant
- spontaneous curvature
- bending modulus
- bending energy
- Helfrich curvature energy
- fluid membrane
- complex liquid
- flexible surface model
- micelle
- counterion
- Poisson-Boltzmann equation
- cell model
- L3 phase
- sponge phas
- Physical chemistry
- Fysikalisk kemi