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Adsorption of nonionic amphiphiles to solid surfaces

Brinck, Johanna LU (1999)
Abstract
In this study, the adsorption of nonionic amphiphiles from aqueous solutions to solid, planar surfaces is investigated using null ellipsometry. This technique allows independent measurements of the amounts adsorbed at the surface and of the mean optical thickness of the adsorbed layer. The time resolution is sufficient for investigating the dynamics of adsorption and desorption in systems of this type.



Detailed experimental studies of the processes involved in the formation and dissolution of pure and binary polyethylene glycol monoalkyl ether surface structures at the silica-water interface were carried out. A theoretical model was developed for interpreting the experimental data and for gaining an understanding of... (More)
In this study, the adsorption of nonionic amphiphiles from aqueous solutions to solid, planar surfaces is investigated using null ellipsometry. This technique allows independent measurements of the amounts adsorbed at the surface and of the mean optical thickness of the adsorbed layer. The time resolution is sufficient for investigating the dynamics of adsorption and desorption in systems of this type.



Detailed experimental studies of the processes involved in the formation and dissolution of pure and binary polyethylene glycol monoalkyl ether surface structures at the silica-water interface were carried out. A theoretical model was developed for interpreting the experimental data and for gaining an understanding of these processes at a molecular level. For the pure surfactant systems, the combination of theory and experiment led to an increased understanding of the influence that a number of surfactant and flow-cell related parameters have on the adsorption and desorption kinetics. An extension of the work to binary surfactant systems revealed the importance of considering the individual paths of adsorption and desorption for each component. Large changes in the surface composition upon rinsing were discovered in binary systems in which there was a significant difference in surfactant cmc.



Studies of the addition of long-chain alcohols to aqueous solutions of polyethylene glycol monoalkyl ethers in contact with a silica surface demonstrated that small amounts of alcohol that are added can give rise to large increases in the total amount adsorbed. Just as with the binary surfactant systems, mixtures of surfactants with alcohol or with oil were shown to produce segregated desorption paths.



Finally, adsorption from an aqueous solution of a fatty acid to a hydrophobic surface was found to be very sensitive to the pH of the solution. A close correlation was observed between the pH dependence of the fouling of the hydrophobic membranes and the experimentally determined adsorption at the planar hydrophobic surface. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Manne, S., Dept. of Physics, Univ. of Arizona, Tucson, AZ, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Physical chemistry, silica, solubilisation, self assembly, ellipsometry, mixed micelles, surfactant, kinetics, Adsorption, desorption, Fysikalisk kemi
pages
144 pages
publisher
Physical Chemistry 1, Lund University
defense location
Lecture Hall C, Center for Chemistry and Chemical Engineering, Lund
defense date
1999-03-13 10:15
external identifiers
  • Other:ISRN: LUNKDL/NKFK--99/1046--SE
ISBN
91-628-3411-8
language
English
LU publication?
yes
id
402f491d-6cf2-4841-af82-35efda4cf594 (old id 39340)
date added to LUP
2007-06-20 12:10:52
date last changed
2016-09-19 08:45:01
@misc{402f491d-6cf2-4841-af82-35efda4cf594,
  abstract     = {In this study, the adsorption of nonionic amphiphiles from aqueous solutions to solid, planar surfaces is investigated using null ellipsometry. This technique allows independent measurements of the amounts adsorbed at the surface and of the mean optical thickness of the adsorbed layer. The time resolution is sufficient for investigating the dynamics of adsorption and desorption in systems of this type.<br/><br>
<br/><br>
Detailed experimental studies of the processes involved in the formation and dissolution of pure and binary polyethylene glycol monoalkyl ether surface structures at the silica-water interface were carried out. A theoretical model was developed for interpreting the experimental data and for gaining an understanding of these processes at a molecular level. For the pure surfactant systems, the combination of theory and experiment led to an increased understanding of the influence that a number of surfactant and flow-cell related parameters have on the adsorption and desorption kinetics. An extension of the work to binary surfactant systems revealed the importance of considering the individual paths of adsorption and desorption for each component. Large changes in the surface composition upon rinsing were discovered in binary systems in which there was a significant difference in surfactant cmc.<br/><br>
<br/><br>
Studies of the addition of long-chain alcohols to aqueous solutions of polyethylene glycol monoalkyl ethers in contact with a silica surface demonstrated that small amounts of alcohol that are added can give rise to large increases in the total amount adsorbed. Just as with the binary surfactant systems, mixtures of surfactants with alcohol or with oil were shown to produce segregated desorption paths.<br/><br>
<br/><br>
Finally, adsorption from an aqueous solution of a fatty acid to a hydrophobic surface was found to be very sensitive to the pH of the solution. A close correlation was observed between the pH dependence of the fouling of the hydrophobic membranes and the experimentally determined adsorption at the planar hydrophobic surface.},
  author       = {Brinck, Johanna},
  isbn         = {91-628-3411-8},
  keyword      = {Physical chemistry,silica,solubilisation,self assembly,ellipsometry,mixed micelles,surfactant,kinetics,Adsorption,desorption,Fysikalisk kemi},
  language     = {eng},
  pages        = {144},
  publisher    = {ARRAY(0x833c478)},
  title        = {Adsorption of nonionic amphiphiles to solid surfaces},
  year         = {1999},
}