Intrinsic low-dielectric Cardo polyimide with high heat resistance, high transparency, and low birefringence
Hong Li,
Weiyi Jin,
Weiyu Zhang,
Jie Li,
Jiaqi Ji,
Yi Tang,
Tianqi Yang,
Shujiang Zhang,
Haixia Yang,
Chenliang Gong
Affiliations
Hong Li
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China; Key Laboratory of Science and Technology on High-tech Polymer Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
Weiyi Jin
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Weiyu Zhang
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Jie Li
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Jiaqi Ji
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Yi Tang
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Tianqi Yang
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
Shujiang Zhang
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China; Corresponding authors.
Haixia Yang
Key Laboratory of Science and Technology on High-tech Polymer Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; Corresponding authors.
Chenliang Gong
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China; Corresponding authors.
Low-dielectric, transparent, and high-heat-resistant polyimide (PI) films are vital for flexible electronics and high-frequency communication devices. However, balancing these properties within intrinsic polyimides remains a significant challenge. In this work, a nonplanar diamine monomer, 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9-bis(4-nitrophenyl)-9H-fluorene (BTFDA), containing a Cardo structure and four trifluoromethyl groups, was synthesized and copolymerized with commercial monomers to produce a series of polyimides (CPI-X). These CPI-X exhibit exceptional heat resistance, with glass transition temperatures (Tg) exceeding 350 °C, decomposition temperatures (Td5 %) above 530 °C, and low thermal expansion coefficients (CTE < 20.8 ppm/K). Additionally, they have excellent optical properties with over 92 % transparency at 450 nm and low birefringence (Δn = 0.00042). They also demonstrate good hydrophobicity with low water absorption (Ma% = 0.04 %) and high-water contact angles (Ca = 97.6°). Most importantly, the CPI-X films show excellent dielectric properties (Dk = 2.25, Df = 0.00365 at 1 MHz, Dk = 2.13, Df = 0.0065 at 10 GHz). Such intrinsic PI films with low Dk values may be ideal candidates for next-generation interlayer media.
