Development of polyimides for opto-electronic integrated circuit

从分子轨道计算的模型化合物，很明显，一个强大的分子内电荷转移的特点，第一激发态，这种性质的基础上占主导地位的HOMO-LUMO转变的芳香族聚酰亚胺的着色。合成了多种具有多脂环结构的四羧酸二酐，并与芳香族或脂肪族二胺进行了缩聚反应。完全酰亚胺化的脂肪族聚酰亚胺膜可溶于有机溶剂，如DMAc。该聚酰亚胺具有良好的热稳定性，5%失重温度范围为450-500℃，玻璃化温度高于290℃。柔性聚酰亚胺膜具有1.5-2.6 Gpa的拉伸模量范围和52-96 Mpa的拉伸强度范围。这些薄膜是完全无色的，并且在可见光区的透射率超过85%。聚酰亚胺具有1.52至1.62的平均折射率范围，并且双折射率几乎为零。根据修正的麦克斯韦方程由折射率估计的介电常数为2.55-2.89。这些聚酰亚胺可用于微电子或光电子应用。

From the molecular orbital calculation of the model compounds, it was evident that a strong intramolecular charge transfer characterized the first excited state, and this nature based on the predominant HOMO-LUMO transition contributed to the coloration of aromatic polyimides. Various kinds of tetracarboxylic dianhydride with a polyalicyclic structure were synthesized and polycondensated with aromatic or aliphatic diamines. The fully imidized aliphatic polyimide films were soluble in organic solvents such as DMAc. The polyimides had good thermal stability with the 5% weight loss temperature range of 450-500℃ and exhibit higher Tg's over 290℃. The flexible polyimide films possessed a tensile modulus range of 1.5-2.6 Gpa and a tensile strength range of 52-96 Mpa. These films were entirely colorless, and the transparencies in the visible region were over 85%. The polyimides had an average refractive index range of 1.52 to 1.62, and the birefringencies were nearly zero. The dielectric constants that were estimated from the refractive index according to the modified Maxwell equation were 2.55-2.89. These polyimides may be of interest for microelectronics or opto-electronics applications.