cess, was observed. This may be due to a side reaction during the irradiation with 254-nm light. The photodimer may produce photodimerization by another remaining double bond on prolonged irradiation. Thus, the absorption peak at 270 nm decreased gradually on continued irradiation.
ConclusionsPrevious studies in the intermolecular reactions of LB films have been limited mainly to photopolymerization and photodimerization. In this study, the intermolecular photoreversible reaction in an LB films has been found for the first time, although the photoreversible reaction of cinnamylideneacetic acid has already been known in polymer film or in low-temperature glassy matrix. Originally, one might expect that these photoreversible systems are more favorable in LB films than in polymers. However, the reversibility was still low for the LB film of 2a, similarly to the polymer film of poly(vinyl cinnamylideneacetate). This is due to the overlapping of the absorption spectra of 2a and the photodimer of 2a and also to the side reaction arising from the chromophore containing two double bonds. Therefore, further investigations are required to find other chromophores for the improvement of reversibility.(41) MS IR, and *H and 13C NMR spectra for the compounds (four acids and their methyl or ethyl esters) in this work are saved in the Spectral Data Bank System (SDBS) constructed by our laboratory (NC-LI) in the Research Information Processing System (RIPS) of Tsukuba Research Center. The spectral patterns for the compounds are available on request.
Polyimide films based on either 3, 3′, 4, 4′‐benzophenone tetracarboxylic acid dianhydride or pyromellitic dianhydride with 4,4′‐oxydianiline have been doped with copper(I) and copper(II) complexes. High‐quality, flexible, glass‐cast films have been obtained which exhibit increased softening temperatures and lower polymer decomposition temperatures. The atmosphere and glass sides of the films are quite different. The copper(I) dopant is oxidized on the air side of the film, while the glass side contains predominantly copper (I). In the copper(II) case most of the copper appears on the air side as a silvery substance in the Cu(II) state. Chemical as well as ion etching can remove this material. Electrical resistivity of the copper(II)‐doped films is decreased by three to five orders of magnitude relative to the polymer alone.
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