The carbazole-bound ferrocenium salt as a specific cationic photoinitiator upon near-UV and visible LEDs (365–405 nm)

Jing Zhang, Damien Campolo, Frederic Dumur, Pu Xiao, Didier Gigmes, Jean Pierre Fouassier, Jacques Lalevée

Research output: Contribution to journalArticleResearchpeer-review

47 Citations (Scopus)

Abstract

Abstract: A carbazole-bound ferrocenium salt [i.e., (η6-Carbazole) (η5-cyclopentadienyl) iron hexafluorophosphate—FS] is proposed as an efficient photoinitiator for the cationic ring-opening polymerization of epoxides under air upon the exposure to a near-UV LED at 385 nm or a visible LED at 405 nm. When using this ferrocenium salt FS (0.2 wt%)/diphenyliodonium hexafluorophosphate or FS (0.2 wt%)/diphenyliodonium hexafluorophosphate/N-vinylcarbazole, final epoxide conversions of 55–66 % can be obtained after 800 s of irradiation at 385 or 405 nm. Reference cationic photoinitiators (i.e., diphenyliodonium hexafluorophosphate; 9-(4-hydroxyethoxyphenyl) thianthrenium hexafluorophosphate and triphenylsulfonium hexafluorophosphate) are unable to initiate the epoxide polymerization under the same conditions. The photochemical mechanisms for the formation of the initiating species are studied using steady-state photolysis, cyclic voltammetry, laser flash photolysis and electron spin resonance spin-trapping techniques. Molecular orbital calculations help to describe the absorption properties and the initiation step. The performance attained when using FS alone is really promising for applications under soft near-UV or visible light-emitting diode irradiation. Graphical abstract: [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)493-507
Number of pages15
JournalPolymer Bulletin
Volume73
Issue number2
DOIs
Publication statusPublished - Feb 2016
Externally publishedYes

Keywords

  • Cationic photopolymerization
  • Ferrocenium salt
  • LEDs
  • Photoinitiator

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