Preparation and Function of Novel Polyimide Derivatives

本项目首次阐明了聚酰亚胺凝胶的制备和性能。通过（1）聚酰胺酸的自发凝胶化，（2）交联剂的加入，和（3）聚酰亚胺链的化学交联制备聚酰亚胺凝胶。异氰酸酯是交联剂之一，其化学结构对凝胶化反应有影响，在水-NMP混合溶液中观察到聚酰亚胺凝胶的体积相变现象。根据溶剂，体积变化连续或不连续地发生。其机理涉及到氢键和介电性的变化，通过相变过程中荧光的变化也观察到了这些现象。聚酰亚胺凝胶的荧光效率高于或高于普通聚酰亚胺。聚酰亚胺凝胶的吸光度小于常规聚酰亚胺膜，表明它们具有小的介电常数。这一特性是聚酰亚胺凝胶在高速电子学应用中的一大优势。

Preparation and properties of polyimide gels were clarified for the first time under this project. Polymide gels were prepared by (1) spontaneous gelation of polyamide acids, (2) addition of crosslinking reagent, and (3) chemically crosslinking of polyimide chains. Isocianates are one of the crosslinking reagents, whose chemical structure affects on the gelation reactions.Volume phase change phenomena of the polyimide gels were observed in Water-NMP mixed solution. The volume change occurs continuously or discontinuously depending on the solvent. The mechanism involves change of hydrogen bonds and dielectricity of the solvents.Those phenomena were also observed by the fluorescence change during phase transition. Fluorescence efficiency of the polyimide gels was higher than or dinary polyimides. Absorbance of the polyimide gels was smaller than conventional polyimide films, showing that they have small dielectric constants. This properties is one of the great advantage of polyimide gels in applying high speed electronics.