Exceptionally thermostable and soluble aromatic polyimides with special characteristics: intrinsic ultralow dielectric constant, static random access memory behaviors, transparency and fluorescence
A series of high-performance multifunctional polyimides with exceptional thermostability and solubility (Tg as high as 494 °C and, at the same time, well soluble in common organic solvents) were successfully designed and synthesized by introducing a typical aromatic rigid trifluoromethyl-containing moiety with special non-planar and conjugated characteristics into the polymer backbone. Additionally, these polyimides show light color (one even colorlessness) and transparency, intrinsic ultralow dielectric constant (k, k ≈ 1.93), and electrical bistability characteristics (ON/OFF ratio as high as 107, working voltage as low as 1.5 V) simultaneously. The excellent thermal stability and solubility allow them to undergo the high temperature process (over 400 °C) in the preparation of photoelectric devices (like PVD or PECVD), or the highly efficient, continuous roll-to-roll process. The as-synthesized polymers are ideal potential candidates for practical applications in the fields of ultra-large-scale integration (ULSI), high-performance polymer memory devices, flexible displays, thin film PV industries, and wearable electronics.