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Controlling Polymerization Initiator Concentration in Mesoporous Silica Thin Films

Krohm, Fabio and Didzoleit, Haiko and Schulze, Marcus and Dietz, Christian and Stark, Robert W. and Hess, Christian and Stühn, Bernd and Brunsen, Annette (2014):
Controlling Polymerization Initiator Concentration in Mesoporous Silica Thin Films.
In: Langmuir, pp. 369-379, 30, (1), ISSN 0743-7463, [Online-Edition: http://dx.doi.org/10.1021/la404004f],
[Article]

Abstract

We present a strategy toward controlled polymer density in mesopores by specifically adjusting the local amount of polymerization initiator at the pore wall. The polymerization initiator concentration as well as the polymer functionalization has a direct impact on mesoporous membrane properties such as ionic permselectivity. Mesoporous silica-based thin films were prepared with specifically adjusted amount of polymerization initiator (4-(3-triethoxysilyl)propoxybenzophenone (BPSilane)) or initiator binding functions ((3-aminopropyl)triethoxysilane (APTES)), directly and homogeneously incorporated into the silica wall pursuing a sol-gel-based co-condensation approach. The amount of polymerization initiator was adjusted by varying its concentration in the sol-gel precursor solution. The surface chemistry, porosity, pore accessibility, and reactivity of the surface functional groups were investigated by using infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray reflectometry, ellipsometry, atomic force microscopy, and transmission electron microscopy. We could gradually modify the amount of reactive polymerization initiators in these mesoporous membranes. Mesopores were maintained for APTES containing films for all tested ratios up to 25 mol % and for BPSilane containing films up to 15 mol %. These films showed accessible and charge-dependent ionic permselectivity and an increasing degree of functionalization with increasing precursor ratio. This approach can directly result in control of polymer grafting density in mesoporous films and thus has a direct impact on applications such as the control of ionic transport through mesoporous silica membranes.

Item Type: Article
Erschienen: 2014
Creators: Krohm, Fabio and Didzoleit, Haiko and Schulze, Marcus and Dietz, Christian and Stark, Robert W. and Hess, Christian and Stühn, Bernd and Brunsen, Annette
Title: Controlling Polymerization Initiator Concentration in Mesoporous Silica Thin Films
Language: English
Abstract:

We present a strategy toward controlled polymer density in mesopores by specifically adjusting the local amount of polymerization initiator at the pore wall. The polymerization initiator concentration as well as the polymer functionalization has a direct impact on mesoporous membrane properties such as ionic permselectivity. Mesoporous silica-based thin films were prepared with specifically adjusted amount of polymerization initiator (4-(3-triethoxysilyl)propoxybenzophenone (BPSilane)) or initiator binding functions ((3-aminopropyl)triethoxysilane (APTES)), directly and homogeneously incorporated into the silica wall pursuing a sol-gel-based co-condensation approach. The amount of polymerization initiator was adjusted by varying its concentration in the sol-gel precursor solution. The surface chemistry, porosity, pore accessibility, and reactivity of the surface functional groups were investigated by using infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray reflectometry, ellipsometry, atomic force microscopy, and transmission electron microscopy. We could gradually modify the amount of reactive polymerization initiators in these mesoporous membranes. Mesopores were maintained for APTES containing films for all tested ratios up to 25 mol % and for BPSilane containing films up to 15 mol %. These films showed accessible and charge-dependent ionic permselectivity and an increasing degree of functionalization with increasing precursor ratio. This approach can directly result in control of polymer grafting density in mesoporous films and thus has a direct impact on applications such as the control of ionic transport through mesoporous silica membranes.

Journal or Publication Title: Langmuir
Volume: 30
Number: 1
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Physics of Surfaces
DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
Exzellenzinitiative
Exzellenzinitiative > Clusters of Excellence
07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
07 Department of Chemistry > Fachgebiet Technische Chemie
Zentrale Einrichtungen
Exzellenzinitiative > Clusters of Excellence > Center of Smart Interfaces (CSI)
Date Deposited: 08 Jun 2016 09:18
Official URL: http://dx.doi.org/10.1021/la404004f
Identification Number: doi:10.1021/la404004f
Funders: The authors thank the Landesoffensive zur Entwicklung Wissenschaftlich-okonomischer Exzellenz (LOEWE Soft Control) for financial support of this work as well as the Robert Bosch Stiftung and the Fonds der chemischen Industrie.
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