Triplet Energy Transfer Strategy for Visible Light Activation of Bio‐Based Oxime Esters in…

Abstract

Visible‐light and solar photopolymerization require photoinitiating systems that combine high reactivity, formulation stability, and biological safety. Here, we present a triplet energy transfer strategy that couples bio‐based benzoyl oxime esters, prepared from bio‐derived aldehydes, with the high‐triplet‐energy visible sensitizer 2‐isopropylthioxanthone (ITX), converting UV‐absorbing oxime ester scaffolds into efficient metal‐free photoinitiators for 405 nm LED and sunlight irradiation. Quantum chemical calculations, electrochemical analysis, laser flash photolysis, ESR spin trapping, and in situ FTIR reveal that Dexter‐type triplet–triplet energy transfer from ITX selectively populates the reactive triplet states of the oxime esters, while the electron pathway is disfavored. Subsequent N─O bond cleavage and rapid decarboxylation generate initiating phenyl radicals. The BE2+ITX formulation affords faster curing, higher conversion, and deeper through‐cure than BE2 or ITX alone, while matching or surpassing benchmark onium and amine systems with favorable cytocompatibility and storage stability. This triplet‐energy‐driven design rule enables modular development of greener photoinitiators for high‐resolution 3D printing and ambient curing.

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Cite

BibTeX RIS

BibTeX

@article{yang2026triplet,
  title = {{Triplet Energy Transfer Strategy for Visible Light Activation of Bio‐Based Oxime Esters in Photopolymerization and 3D Printing}},
  author = {Kaidan Yang and Céline Dietlin and Coralie Ohl and Margot Manivel and Fabrice Morlet-Savary and Michael Schmitt and Gérard Audran and Jean‐patrick Joly and Jing Zhang and Pu Xiao and Jacques Lalevée},
  journal = {Small},
  year = {2026},
  month = jul,
  doi = {10.1002/smll.74715},
  url = {https://hal.science/hal-05743785v1},
  note = {CC BY 4.0},
}

RIS

TY  - JOUR
TI  - Triplet Energy Transfer Strategy for Visible Light Activation of Bio‐Based Oxime Esters in Photopolymerization and 3D Printing
AU  - Kaidan Yang
AU  - Céline Dietlin
AU  - Coralie Ohl
AU  - Margot Manivel
AU  - Fabrice Morlet-Savary
AU  - Michael Schmitt
AU  - Gérard Audran
AU  - Jean‐patrick Joly
AU  - Jing Zhang
AU  - Pu Xiao
AU  - Jacques Lalevée
PY  - 2026
DA  - 2026/07/23
JO  - Small
DO  - 10.1002/smll.74715
UR  - https://hal.science/hal-05743785v1
AB  - Visible‐light and solar photopolymerization require photoinitiating systems that combine high reactivity, formulation stability, and biological safety. Here, we present a triplet energy transfer strategy that couples bio‐based benzoyl oxime esters, prepared from bio‐derived aldehydes, with the high‐triplet‐energy visible sensitizer 2‐isopropylthioxanthone (ITX), converting UV‐absorbing oxime ester scaffolds into efficient metal‐free photoinitiators for 405 nm LED and sunlight irradiation. Quantum chemical calculations, electrochemical analysis, laser flash photolysis, ESR spin trapping, and in situ FTIR reveal that Dexter‐type triplet–triplet energy transfer from ITX selectively populates the reactive triplet states of the oxime esters, while the electron pathway is disfavored. Subsequent N─O bond cleavage and rapid decarboxylation generate initiating phenyl radicals. The BE2+ITX formulation affords faster curing, higher conversion, and deeper through‐cure than BE2 or ITX alone, while matching or surpassing benchmark onium and amine systems with favorable cytocompatibility and storage stability. This triplet‐energy‐driven design rule enables modular development of greener photoinitiators for high‐resolution 3D printing and ambient curing.
SN  - 1613-6810
SN  - 1613-6829
ER  -

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