Molecular Engineering of Intrinsic Chromophoric Polyimides: Chemically Amplified Color Photoresists for Advanced Optical Systems

Color photoresists represent a cornerstone technology in advanced optical systems, enabling critical functionalities ranging from flexible display pixel manufacturing to direct lithography of antidust color coatings for space exploration equipment. While conventional dye-polymer composite photoresists dominate industrial applications, their intrinsic limitations in thermal stability, mechanical durability, electrical insulation, and long-term color stability fundamentally restrict their deployment in extreme environments. This study pioneers a molecular engineering strategy to overcome these challenges through the development of intrinsically colored photosensitive polyimides (PSPIs). By strategically incorporating anthraquinone chromophores into polyimide backbones and/or terminal groups, we achieved precise spectral control across the visible spectrum (RGB tricolors). The optimized four-component photoresist system integrates PSPIs, photoacid generators, alkaline additives, and cross-linkers, enabling high-resolution lithography (10 μm feature size). The synthesized PSPIs exhibit high thermal performance with glass transition temperatures exceeding 270 °C and 5% decomposition temperatures above 410 °C. Crucially, they demonstrate outstanding color stability under multienvironmental stresses including cryogenic conditions (-193 °C), thermal cycling (140 °C), and prolonged UV exposure. Therefore, this molecular design strategy establishes a scalable platform for engineering mission-adaptable colored photoresists simultaneously without compromising the exceptional material properties inherent to polyimides.