COATING THICKNESS EFFECT ON THE ORIENTATION AND THERMAL-EXPANSION COEFFICIENT OF POLYIMIDE FILMS
COATING THICKNESS EFFECT ON THE ORIENTATION AND THERMAL-EXPANSION COEFFICIENT OF POLYIMIDE FILMS
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DOI：
10.1016/0032-3861(92)90011-k
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发表时间：
1992-01-01
期刊：
影响因子：
4.6
通讯作者：
LIAO, CN
中科院分区：
文献类型：
--
作者：
JOU, JH;HUANG, PT;LIAO, CN
从X-射线衍射实验，它是观察到，在基板上固化的聚酰亚胺薄膜是这样的取向，酰亚胺链优先排列在膜的平面方向。 对于具有刚性棒聚酰亚胺的膜，膜取向特别突出，并且随着膜厚度的增加而显著降低。 涂层厚度对聚酰亚胺膜的取向和有序性的影响在纯均苯四酸二酐-对苯二胺（PMDA-PDA）膜中最显著，在具有50%均苯四酸二酐-4，4 '-二氨基二苯醚（PMDA-ODA）和50% PMDA-PDA的膜中稍小，并且在具有100% PMDA-ODA的膜中相对不显著。 根据傅里叶变换红外衰减全反射光谱实验中的C=O和C-N伸缩吸收带，位于膜中心附近的酰亚胺分子比表面附近的酰亚胺分子表现出更差的结构有序性。 这揭示了为什么随着膜厚的增加，平均膜取向减小，相应的热膨胀系数增加。
From X-ray diffraction experiments, it is observed that on-substrate cured polyimide films are so oriented that the imide chains are preferentially aligned in the plane direction of the films. For films with rigid-rod polyimide, film orientation is especially prominent and decreases significantly as the film thickness increases. The effect of coating thickness on the orientation and ordering of polyimide films is most pronounced in pure pyromellitic dianhydride-p-phenylenediamine (PMDA-PDA) films, slightly less in films with 50% pyromellitic dianhydride-4,4'-oxydianiline (PMDA-ODA) and 50% PMDA-PDA, and relatively insignificant in those with 100% PMDA-ODA. According to the C=O and C-N stretching absorption bands from Fourier-transform infra-red-attenuated total reflectance spectroscopic experiments, imide molecules located near the centre of the film exhibit poorer structure ordering than those near the surface. This reveals why the average film orientation decreases and the corresponding thermal expansion coefficient increases with increase of film thickness.