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Photoinduced electron/energy transfer (PET)-reversible addition–fragmentation chain transfer polymerization (RAFT) and conventional photoinitiated RAFT were used to synthesize polymer networks. In this study, two different metal catalysts, namely, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) and zinc tetraphenylporphyrin (ZnTPP), were selected to generate two different catalytic pathways, one with Ir(ppy)3 proceeding through an energy-transfer pathway and one with ZnTPP proceeding through an electron-transfer pathway. These PET-RAFT systems were contrasted against a conventional photoinitated RAFT process. Mechanically robust materials were generated. Using bulk swelling ratios and degradable cross-linkers, the homogeneity of the networks was evaluated. Especially at high primary chain length and cross-link density, the PET-RAFT systems generated more uniform networks than those made by conventional RAFT, with the electron transfer-based ZnTPP giving superior results to those of Ir(ppy)3. The ability to deactivate radicals either by RAFT exchange or reversible coupling in PET RAFT was proposed as the mechanism that gave better control in PET-RAFT systems.
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PET-RAFT to expand the surface-modification chemistry of melt coextruded nanofibers
Polymeric nanofibers have been widely used as scaffolds for tissue engineering, drug delivery, and filtration applications, among many others. A high throughput melt coextrusion technique and post-processing functionalization chemistry was recently developed to fabricate functional fibers with nanoscale dimensions. This manuscript expands upon the development of nanofiber modification chemistry by functionalizing fiber mats using a surface-initiated photo-induced electron transfer reversible addition–fragmentation chain transfer (PET-RAFT) polymerization technique. PET-RAFT allows for the fabrication of chemically diverse nanofiber systems initiated with light, preventing the need for high temperature thermal initiators. This manuscript describes the scope of monomers polymerizable via this technique on the surface of poly ε-caprolactone (PCL) nanofibers. The PET-RAFT modification chemistry is used to introduce block copolymers, provide multiple modifications using an orthogonal RAFT-ATRP system, induce spatial photopatterning and to establish cell-adhesive capabilities. The development of surface-initiated PET-RAFT adds an additional tool to a growing strategy for nanofiber functionalization.
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- Award ID(s):
- 2011924
- PAR ID:
- 10413536
- Date Published:
- Journal Name:
- Polymer Chemistry
- Volume:
- 14
- Issue:
- 9
- ISSN:
- 1759-9954
- Page Range / eLocation ID:
- 1054 to 1063
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2PY01389D
