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Influence of Nanoconfinement on the pKa of Polyelectrolyte Functionalized Silica Mesopores

Brilmayer, Robert ; Kübelbeck, Sonja ; Khalil, Adnan ; Brodrecht, Martin ; Kunz, Ulrike ; Kleebe, Hans‐Joachim ; Buntkowsky, Gerd ; Baier, Grit ; Andrieu‐Brunsen, Annette (2021):
Influence of Nanoconfinement on the pKa of Polyelectrolyte Functionalized Silica Mesopores. (Publisher's Version)
7, In: Advanced Materials Interfaces, 7 (7), Wiley, ISSN 2196-7350,
DOI: 10.26083/tuprints-00019915,
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Item Type: Article
Origin: Secondary publication service
Status: Publisher's Version
Title: Influence of Nanoconfinement on the pKa of Polyelectrolyte Functionalized Silica Mesopores
Language: English
Abstract:

Functionalized ordered mesoporous materials are relevant in technologies, such as drug release, sensing, and separation. To design functionality, the silica framework can be functionalized with responsive molecules or polymers. Often, the pH value in those hybrid materials determines performance. Even though pH/pKa differences between polymers in bulk solutions and nanoscale confinement have been observed, the influence of confinement on pH- and pore filling dependent polyelectrolyte oligomer chain charge has yet not been investigated systematically. Here, mesoporous silica films are functionalized with (2-dimethylamino)ethyl methacrylate) (DMAEMA) and 2-(methacryloyloxy)ethyl phosphate (MEP) oligomers using photoiniferter initiated polymerization. This approach allows a controlled and environmentally friendly mesopore functionalization in water. The obtained oligomer functionalized pores are tunable with respect to pore filling. For both, poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(2-(methacryloxy)ethyl phosphate) (PMEP), the charge generation inside mesopore confinement is significantly delayed toward harsher pH conditions resulting in pKa shifts of 1–2 pH units. Polymer amount and ionic strength show to further influence the pKa of PDMAEMA in mesopores. The technological importance of the pH value in confinement and its effect on enzyme stabilization is demonstrated. Lipase from Aspergillus oryzae loses its activity upon encapsulation in silica nanoparticles at pH values where the enzyme is stable in bulk solution.

Journal or Publication Title: Advanced Materials Interfaces
Volume: 7
Journal volume: 7
Number: 7
Publisher: Wiley
Collation: 10 Seiten
Classification DDC: 500 Naturwissenschaften und Mathematik > 540 Chemie
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 1194: Interaction between Transport and Wetting Processes > Research Area C: New and Improved Applications > C04: Controlled Dynamic Wetting and the Influence of Ionic Mass Transport in Mesoporous Film
Date Deposited: 19 Nov 2021 13:14
Last Modified: 19 Nov 2021 13:15
DOI: 10.26083/tuprints-00019915
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-199152
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19915
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