Magnetic filed effect on sensitized photocrosslinking reaction of azidomethylated polytsyrene

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Abstract

Characteriscs curves for the lithographic sensitivity of poly(styrene-co-vinylblenzyl azide) (AZMA) with such sensitizer as 2,4-diisopentvlthioxanthone (DITX), 2-chlorothioxanthone (CTX), and Michier's ketone wer emeasured in the basence and in the presence of a magnetic filed. By the application of a magnetic field, the get fraction increases, and efficiency of photocrosslink formation increases by ≈ 45% (at 0.1 T) for AZMA/DITX and by ≈ 20% (at 0.5 T) for AZMS/CTX. Senstization mechanism was investigated by measuring UV, IR, and FT-IR spectra, and AZMS is found to be sensitized effectively by DITX and CTX through the triplet energy transfer, and to produce the triplet nitrene as an intermediate. The magnetic field effect on photocrosslink formation of AZMS/sensitizer systems is interpreted in term of the radical pair model of intermediate species which is formed by hydrogen abstraction of the nitrene from the sensitizer.

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