Structural Studies of Surfactants at Interfaces
Abstract
This thesis consists of a collection of studies on surfactant adsorption at different
interfaces. Particularly, this dissertation focuses on adsorption processes occurring at
buried interfaces (solid-liquid and liquid-liquid). Because of complexity in the sample
environment, the study of buried interfaces is experimentally challenging.
Neutron reflectivity enables the study of adsorption processes at interfaces at atomic
length scale. Furthermore, neutrons can be transmitted through solid substrates,
permitting the analysis of buried interfaces. The technique was used to describe
adsorption processes both qualitatively and quantitatively, delivering information
regarding structure of adsorbed layers and adsorbed amount.
Different investigations were carried out during the PhD and the results are grouped into
two main sections. Investigations at the solid-liquid interface are presented in the first
section. Chapter 3 provides an example of structural study of complex multi-layers at
the silicon-water interface; a surfactant adsorption study at the technologically relevant
metal-oil interface is presented in Chapter 4.
The second section discusses a series of neutron reflectivity experiments at the
important oil-water interface. The structural study of a series of non-ionic dodecanol
ethoxylate surfactants is discussed in Chapter 6. The structure of a lipid monolayer as
model for a biological membrane is reported in Chapter 7. Chapter 8 is a comparative
study of fatty acid-alkylated azacrown ether co-adsorption at the air-water and oil-water
interface. These mixtures are used for metal ion extraction processes. This was the first
analysis of a surfactant mixture at the oil-water interface using neutron reflectivity.
Some of the studies reported here are the first of their kind and the advances affect
different technologically and biologically relevant areas. As a result of this PhD project
a number of follow-up studies have been planned and several neutron reflectivity
experiments will be performed in the future to further explore these interesting areas of
science.
Authors
Campana, MarioCollections
- Theses [4352]