Direct Ink Writing of High Performance Architectured Polyimides with Low Dimensional Shrinkage

Abstract

Despite of the outstanding chemical‐resistance, thermal and thermomechanical properties, and dielectric performance of three dimensional (3D) printed polyimides, the high dimensional shrinkage (more than 45%) between the as‐printed and final imidized objects may become the biggest obstacle on its practical applications. In this work, the authors present a two‐state curing strategy for realizing 3D printing of high performance polyimides via UV‐assisted direct ink writing (DIW) of poly (amide acid) (PAA) followed by thermal imidization. More specifically, PAA precursors modified with hydroxyethyl methacrylate are printed and thermally imidized at an elevated temperature to form 3D objects, which demonstrate a dimensional shrinkage less than 6%. The outstanding performances regarding thermal resistance, solvent‐proofing, and mechanical strength are comprehensively characterized, and some attracting polyimide functional 3D devices, such as polyimide spring and enameled wire, are readily achieved. Their DIW strategy realizes three‐dimensional polyimide architectures with low volume shrinkage and provides a tremendous potential for 3D printing of polyimides in many fields including aerospace, automobile, microelectronics, and engineering.