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

Abstract

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.