Films with optical transmittance of >80% between 400 and 750 nm and with coefficient of thermal expansion less than 20 ppm/° C. are prepared from aromatic polyamides that are soluble in polar organic solvents yet have glass transition temperatures >300° C. The films are cross-linked in the solid state by heating at elevated temperatures for short periods of time in the presence of multifunctional epoxides. Surprisingly, the optical and thermal properties of the films do not change significantly during the curing process. The temperature required for the crosslinking process to take place can be reduced by the presence of a few free, pendant carboxyl groups along the polyamide backbones. The films are useful as flexible substrates for electronic displays and photovoltaic devices.
薄膜在 400 纳米到 750 纳米之间的光学透射率大于 80%,热膨胀系数小于 20 ppm/°C,由可溶于极性有机溶剂但
玻璃化转变温度大于 300°C 的芳香族聚酰胺制备而成。令人惊讶的是,在固化过程中,薄膜的光学和热学特性没有发生明显变化。由于聚酰胺骨架上存在一些游离的悬垂羧基,因此可以降低交联过程所需的温度。这种薄膜可用作电子显示器和光伏设备的柔性基板。