The Influence of Irradiation Wavelength on the Growth of Polymer Brushes by SI-PET-RAFT Polymerization
Date
2025-02-22
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Polymer Science
Abstract
An effective method to produce well-defined polymer brushes with high spatial, temporal, and sequence control is to employ a photoredox catalyst in photo-mediated polymerization. Generally, the excitation wavelength is chosen as the absorption maximum of the photocatalyst, however, it is not clear if that corresponds to the best photochemical activity for producing polymer brushes. Herein, we systematically examine wavelength-by-wavelength resolved polymer brush growth using surface-initiated photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT), of four monomer types. The absorption spectra of the water-soluble photocatalyst (ZnTPPS44−) and the brush growth at each irradiation wavelength were examined as photochemical activity plots. Our results show a striking disparity between the absorbance of the photoredox catalyst and the maximum brush height. Moreover, the photochemical activity with wavelength was highly dependent on the nature of the monomer used. In addition to displaying a strong wavelength selectivity, a characteristic red-shift in the brush height relative to the lowest possible energy transition of the photocatalyst's absorbance spectrum was observed. We anticipate this work will better inform on wavelength choice for SI-PET-RAFT polymerization of polymer brushes.
Graphical Abstract available at: https://doi.org/10.1002/pol.20241148
The use of SI-PET-RAFT has been gaining momentum for producing thick, homogenous, functional polymer brushes, in an oxygen-tolerant manner. However, the connection between irradiation wavelength and the brush height has not been clear. Herein, we systematically explore the effect of irradiation wavelength on the resulting brush properties, finding a disconnection between photocatalyst absorption and brush thicknesses.
Description
This article was originally published in Journal of Polymer Science. The version of record is available at: https://doi.org/10.1002/pol.20241148.
© 2025 The Author(s). Journal of Polymer Science published by Wiley Periodicals LLC.
This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Keywords
photochemical action plots, photopolymerisation, polymer brushes, SI-PET-RAFT, wavelength- dependence
Citation
Mérai, L., Rymsha, K., Yadav, J., Pester, C.W., Fery, A. and Besford, Q.A. (2025), The Influence of Irradiation Wavelength on the Growth of Polymer Brushes by SI-PET-RAFT Polymerization. J Polym Sci. https://doi.org/10.1002/pol.20241148