Weak polyacid brushes : synthesis, swelling behavior, complex formation and micropatterning
type: CreativeWork
description: In this work, densely end-grafted polymer monolayers, so-called "polymer brushes", were covalently attached to solid planar surfaces and investigated with respect to their properties in contact with aqueous solutions of varying composition. The synthesis of these polymer brushes was performed in two steps. First, an end-functionalized azoinitiator was covalently anchored to silicon wafers and planar glass substrates to form a self-assembled monolayer. Then, a surface-initiated free radical polymerization of vinyl monomers was triggered by thermal cleavage of the initiator ("grafting from" polymerization). By varying the monomer concentration and the polymerization time, the molecular weight of the surface-attached polymer chains and the anchoring density, a characteristic parameter that determines the degree of chain stretching of a polymer brush, could be reproducibly adjusted. Furthermore, different photopatterning strategies were implemented into the concept of surface-initiated polymerization. Using different approaches, positive and negative images of a mask and, in particular, laterally chemically microstructured polymer brushes could be obtained. The focus of this work was on the investigation of the properties of poly(methacrylic acid) (PMAA) brushes, a weak polyelectrolyte whose charge density can be tuned by adjustment of external parameters such as the solution pH-value. The PMAA brushes were swollen in aqueous solutions of different ionic composition and their properties were studied as a function of the valency, size (polarizability), concentration and nature of the ion. In another study, the complex formation of PMAA brushes with oppositely charged surfactants of different alkyl chain lengths was investigated. Stable complexes were formed with multivalent cations and oppositely charged surfactants. The complex formation behavior of PMAA brushes in contact with various small metal ion and oppositely charged surfactant solutions was investigated in detai…
abstract: In this work, densely end-grafted polymer monolayers, so-called "polymer brushes", were covalently attached to solid planar surfaces and investigated with respect to their properties in contact with aqueous solutions of varying composition. The synthesis of these polymer brushes was performed in two steps. First, an end-functionalized azoinitiator was covalently anchored to silicon wafers and planar glass substrates to form a self-assembled monolayer. Then, a surface-initiated free radical polymerization of vinyl monomers was triggered by thermal cleavage of the initiator ("grafting from" polymerization). By varying the monomer concentration and the polymerization time, the molecular weight of the surface-attached polymer chains and the anchoring density, a characteristic parameter that determines the degree of chain stretching of a polymer brush, could be reproducibly adjusted. Furthermore, different photopatterning strategies were implemented into the concept of surface-initiated polymerization. Using different approaches, positive and negative images of a mask and, in particular, laterally chemically microstructured polymer brushes could be obtained. The focus of this work was on the investigation of the properties of poly(methacrylic acid) (PMAA) brushes, a weak polyelectrolyte whose charge density can be tuned by adjustment of external parameters such as the solution pH-value. The PMAA brushes were swollen in aqueous solutions of different ionic composition and their properties were studied as a function of the valency, size (polarizability), concentration and nature of the ion. In another study, the complex formation of PMAA brushes with oppositely charged surfactants of different alkyl chain lengths was investigated. Stable complexes were formed with multivalent cations and oppositely charged surfactants. The complex formation behavior of PMAA brushes in contact with various small metal ion and oppositely charged surfactant solutions was investigated in detai…
author: Konradi, Rupert
keywords: Polymerbürste, Polyelektrolytbürste, Polymethacrylsäure, Quellverhalten, Kation, polyelectrolyte, brush, swelling, radical polymerization, cation
date modified: 2026-07-24T02:22:22Z
provider: University of Freiburg
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Freiburg