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A new positive‐type photoreactive polyimide precursor using 1,4‐dihydropyridine derivative
Author(s) -
Omote Toshihiko,
Yamaoka Tsuguo
Publication year - 1992
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760322117
Subject(s) - polyimide , nifedipine , dissolution , materials science , ether , polymer chemistry , intermolecular force , molecule , chemistry , organic chemistry , nanotechnology , calcium , layer (electronics) , metallurgy
A novel positive‐type polyimide precursor (BPDA/DDE) has been developed and examined. It is synthesized by the polycondensation of biphenyltetracarboxylic acid dianhydride and 4,4′‐diamino‐diphenyl ether, based on systems composed of dimethyl 1,4‐dihydro‐2,6‐dimethyl‐4‐(2‐nitrophenyl)‐3,5‐pyridinecarboxylate (nifedipine). Nifedipine photoconverted quantitatively to 4‐(2′‐nitrosophenyl)‐2,3‐dicarboxymethyl‐3,5‐dimethylpyridine (NDMPy) in a polyimide precursor film. It has been confirmed that nifedipine and NDMPy in the film act as a dissolution inhibitor and as a disolution promotor, respectively. The dissolution inhibition and promotion mechanisms were further investigated and subsequently expressed as follows: (1) Dissolution inhibition is due to resistivity of the polyimide precursor to an alkaline aqueous solution through intermolecular hydrogen bonding between — COOH in the polymer structure and — NH — in nifedipine. (2) Dissolution promotion is due to the hydrogen bond‐breaking by photoconversion from nifedipine to NDMPy and the newly formed intermolecular complex between the COOH and N in NDMPy.The photoreactive polyimide precursor (BPDA/DDE), including 25wt% nifedipine, shows a 170mJ/cm 2 sensitivity and a 5.5 γ value.