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Crystal‐to‐Crystal Photoinduced Electron Transfer Generating Photoacids to Formulate Water‐Borne Photopolymers
Author(s) -
Ichimura Kunihiro,
Aoki Ken'ichi
Publication year - 2007
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200600667
Subject(s) - photopolymer , photoinduced electron transfer , photochemistry , photodissociation , aqueous solution , electron transfer , solvent , materials science , quenching (fluorescence) , reagent , chemistry , photoinitiator , chemical engineering , polymer chemistry , polymer , polymerization , fluorescence , organic chemistry , optics , monomer , physics , engineering
Casting a photopolymer solution to form a film, followed by imagewise photoirradiation and subsequent wet development, leads to photolithography. Whereas the wet development is achievable with aqueous alkali, the emission of an organic solvent as a volatile organic compound (VOC) is usually inevitable during the film casting because ingredients of common photopolymers are insoluble in water. We show here a prototype of water‐borne photopolymers dispersed with milled nanoparticles of poorly water‐soluble photoacid generators (PAGs), which undergo solid‐state photolysis to liberate a photoacid to make a poly(vinyl alcohol) film insoluble in water with the aid of an acid‐sensitive crosslinking reagent. The photolysis of onium‐type PAGs is sensitized in the solid state simply by comilling with water‐insoluble sensitizers to extend spectral sensitivity of this kind of photopolymers. Fluorescence quenching measurements revealed that the solid‐state sensitization occurs through exciton migration in sensitizer particles followed by electron transfer to PAG particles.