کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1672202 | 1008929 | 2009 | 6 صفحه PDF | دانلود رایگان |
We have investigated the photo-induced in-plane anisotropy of the films of two different polyimides (PIs) containing azobenzene in the backbone structure (Azo-PIs), which were synthesized from the same diamine, 4, 4′-diaminoazobenzene (DAAB), and two different dianhydrides, pyromellitic dianhydride (PMDA) or oxydiphthalic anhydride (ODPA). Under the same photo-alignment condition, the in-plane anisotropy of the ODPA–DAAB PI film was significantly larger than that of the PMDA–DAAB PI film. This result shows that the photo-alignment efficiency of the former is higher than that of the latter; i.e. the photo-alignment efficiency of Azo-PI can be improved by changing the backbone structure. We believe that the observed enhancement in the photo-alignment efficiency is attributed to a lowering of the polymer chain rigidity, which is caused by introducing an ether linkage with free rotation around non-parallel bonds into the dianhydride part.
Journal: Thin Solid Films - Volume 518, Issue 2, 30 November 2009, Pages 729–734