Adsorption of anionic surfactants in a nonionic polymer brush experiments, comparison with mean-Field theory, and implications for brush-Particle interaction

Wiebe M. De Vos, Maarten Biesheuvel, Arie De Keizer, Mieke Kleijn, Martien A. Cohen Stuart

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)

Abstract

The adsorption of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) in poly(ethylene oxide) (PEO) brushes was studied using a fixed-angle optical flow-cell reflectometer. We show that, just as in solution, there is a critical association concentration (CAC) for the surfactants at which adsorption in the PEO brush starts. Above the critical micelle concentration (CMC) the adsorption is found to be completely reversible. At low brush density the adsorption per PEO monomer is equal to the adsorption of these surfactants in bulk solution. However, with increasing brush density, the number of adsorbed surfactant molecules per PEO monomer decreases rapidly. This decrease is explained in terms of excluded volume interactions plus electrostatic repulsion between the negatively charged surfactant micelles. Experimentally, a plateau value in the total adsorption is observed as a function of grafting density. The experimental results were compared to the results of an analytical self-consistent field (aSCF) model, and we found quantitative agreement. Additionally, the model predicts that the plateau value found is in fact a maximum. Both experiments and model calculations show that the adsorption scales directly with the polymerization degree of the polymers in the brush. They also show that an increase in the ionic strength leads to an increase in the adsorbed amount, which is explained as being due to a decrease in the electrostatic penalty for the adsorption of the SDS micelles. The adsorption of SDS micelles changes the interactions of the PEO brush with a silica particle. This is illustrated by atomic force microscopy (AFM) measurements of the pull-off force of a silica particle from a PEO brush: at high enough PEO densities, the addition of SDS leads to a very strong reduction in the force necessary to detach the colloidal silica particle from the PEO brush. We attribute this effect to the large amount of negative charge incorporated in the PEO brush due to SDS adsorption.

Original languageEnglish
Pages (from-to)9252-9261
Number of pages10
JournalLangmuir
Volume25
Issue number16
DOIs
Publication statusPublished - 18 Aug 2009
Externally publishedYes

Fingerprint

Mean field theory
Particle interactions
Anionic surfactants
brushes
particle interactions
Brushes
ethylene oxide
Polyethylene oxides
Polymers
surfactants
Adsorption
adsorption
polymers
Sodium dodecyl sulfate
sodium sulfates
Sodium Dodecyl Sulfate
Surface-Active Agents
Experiments
micelles
Micelles

Cite this

De Vos, Wiebe M. ; Biesheuvel, Maarten ; De Keizer, Arie ; Kleijn, Mieke ; Cohen Stuart, Martien A. / Adsorption of anionic surfactants in a nonionic polymer brush experiments, comparison with mean-Field theory, and implications for brush-Particle interaction. In: Langmuir. 2009 ; Vol. 25, No. 16. pp. 9252-9261.
@article{386ff69e49bc4a7dbfa28d70ade35b71,
title = "Adsorption of anionic surfactants in a nonionic polymer brush experiments, comparison with mean-Field theory, and implications for brush-Particle interaction",
abstract = "The adsorption of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) in poly(ethylene oxide) (PEO) brushes was studied using a fixed-angle optical flow-cell reflectometer. We show that, just as in solution, there is a critical association concentration (CAC) for the surfactants at which adsorption in the PEO brush starts. Above the critical micelle concentration (CMC) the adsorption is found to be completely reversible. At low brush density the adsorption per PEO monomer is equal to the adsorption of these surfactants in bulk solution. However, with increasing brush density, the number of adsorbed surfactant molecules per PEO monomer decreases rapidly. This decrease is explained in terms of excluded volume interactions plus electrostatic repulsion between the negatively charged surfactant micelles. Experimentally, a plateau value in the total adsorption is observed as a function of grafting density. The experimental results were compared to the results of an analytical self-consistent field (aSCF) model, and we found quantitative agreement. Additionally, the model predicts that the plateau value found is in fact a maximum. Both experiments and model calculations show that the adsorption scales directly with the polymerization degree of the polymers in the brush. They also show that an increase in the ionic strength leads to an increase in the adsorbed amount, which is explained as being due to a decrease in the electrostatic penalty for the adsorption of the SDS micelles. The adsorption of SDS micelles changes the interactions of the PEO brush with a silica particle. This is illustrated by atomic force microscopy (AFM) measurements of the pull-off force of a silica particle from a PEO brush: at high enough PEO densities, the addition of SDS leads to a very strong reduction in the force necessary to detach the colloidal silica particle from the PEO brush. We attribute this effect to the large amount of negative charge incorporated in the PEO brush due to SDS adsorption.",
author = "{De Vos}, {Wiebe M.} and Maarten Biesheuvel and {De Keizer}, Arie and Mieke Kleijn and {Cohen Stuart}, {Martien A.}",
year = "2009",
month = "8",
day = "18",
doi = "10.1021/la900791b",
language = "English",
volume = "25",
pages = "9252--9261",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "16",

}

Adsorption of anionic surfactants in a nonionic polymer brush experiments, comparison with mean-Field theory, and implications for brush-Particle interaction. / De Vos, Wiebe M.; Biesheuvel, Maarten; De Keizer, Arie; Kleijn, Mieke; Cohen Stuart, Martien A.

In: Langmuir, Vol. 25, No. 16, 18.08.2009, p. 9252-9261.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Adsorption of anionic surfactants in a nonionic polymer brush experiments, comparison with mean-Field theory, and implications for brush-Particle interaction

AU - De Vos, Wiebe M.

AU - Biesheuvel, Maarten

AU - De Keizer, Arie

AU - Kleijn, Mieke

AU - Cohen Stuart, Martien A.

PY - 2009/8/18

Y1 - 2009/8/18

N2 - The adsorption of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) in poly(ethylene oxide) (PEO) brushes was studied using a fixed-angle optical flow-cell reflectometer. We show that, just as in solution, there is a critical association concentration (CAC) for the surfactants at which adsorption in the PEO brush starts. Above the critical micelle concentration (CMC) the adsorption is found to be completely reversible. At low brush density the adsorption per PEO monomer is equal to the adsorption of these surfactants in bulk solution. However, with increasing brush density, the number of adsorbed surfactant molecules per PEO monomer decreases rapidly. This decrease is explained in terms of excluded volume interactions plus electrostatic repulsion between the negatively charged surfactant micelles. Experimentally, a plateau value in the total adsorption is observed as a function of grafting density. The experimental results were compared to the results of an analytical self-consistent field (aSCF) model, and we found quantitative agreement. Additionally, the model predicts that the plateau value found is in fact a maximum. Both experiments and model calculations show that the adsorption scales directly with the polymerization degree of the polymers in the brush. They also show that an increase in the ionic strength leads to an increase in the adsorbed amount, which is explained as being due to a decrease in the electrostatic penalty for the adsorption of the SDS micelles. The adsorption of SDS micelles changes the interactions of the PEO brush with a silica particle. This is illustrated by atomic force microscopy (AFM) measurements of the pull-off force of a silica particle from a PEO brush: at high enough PEO densities, the addition of SDS leads to a very strong reduction in the force necessary to detach the colloidal silica particle from the PEO brush. We attribute this effect to the large amount of negative charge incorporated in the PEO brush due to SDS adsorption.

AB - The adsorption of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) in poly(ethylene oxide) (PEO) brushes was studied using a fixed-angle optical flow-cell reflectometer. We show that, just as in solution, there is a critical association concentration (CAC) for the surfactants at which adsorption in the PEO brush starts. Above the critical micelle concentration (CMC) the adsorption is found to be completely reversible. At low brush density the adsorption per PEO monomer is equal to the adsorption of these surfactants in bulk solution. However, with increasing brush density, the number of adsorbed surfactant molecules per PEO monomer decreases rapidly. This decrease is explained in terms of excluded volume interactions plus electrostatic repulsion between the negatively charged surfactant micelles. Experimentally, a plateau value in the total adsorption is observed as a function of grafting density. The experimental results were compared to the results of an analytical self-consistent field (aSCF) model, and we found quantitative agreement. Additionally, the model predicts that the plateau value found is in fact a maximum. Both experiments and model calculations show that the adsorption scales directly with the polymerization degree of the polymers in the brush. They also show that an increase in the ionic strength leads to an increase in the adsorbed amount, which is explained as being due to a decrease in the electrostatic penalty for the adsorption of the SDS micelles. The adsorption of SDS micelles changes the interactions of the PEO brush with a silica particle. This is illustrated by atomic force microscopy (AFM) measurements of the pull-off force of a silica particle from a PEO brush: at high enough PEO densities, the addition of SDS leads to a very strong reduction in the force necessary to detach the colloidal silica particle from the PEO brush. We attribute this effect to the large amount of negative charge incorporated in the PEO brush due to SDS adsorption.

UR - http://www.scopus.com/inward/record.url?scp=68649119355&partnerID=8YFLogxK

U2 - 10.1021/la900791b

DO - 10.1021/la900791b

M3 - Article

VL - 25

SP - 9252

EP - 9261

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 16

ER -