High-Performance Functional Polyimides Containing Rigid Nonplanar Conjugated Triphenylethylene Moieties

A novel, simple but efficient diamine (TriPEDA) containing rigid nonplanar conjugated triphenylethylene moieties was designed and synthesized through Wittig-Horner and Suzuki coupling reactions. Four kinds of high-performance functional polyirnides were thus prepared by the dipolymerization of TriPEDA and four dianhydrides, respectively. Because of the introduction of the aromatic rigid nonplanar triphenylethylene structure, the polyimides exhibited special fluorescent and resistive switching (ON-OFF) characteristics, as the maximum fluorescence emission of the four polyimides was observed at 472-505 nm in NMP solution and at 473-541 nm in film state. Also these organo-soluble polyimides showed outstanding properties, such as low dielectric constant (even without fluorinated substituents), light color, high glass transition temperatures (359-409 degrees C), thermal stability, and excellent mechanical properties. The memory devices with the configuration of indium tin oxide/polyimides/aluminum (ITO/PI/Al) exhibited distinct volatile memory characteristics of static random access memory (SRAM), with an ON/OFF current ratio of 1 x 10(5) to 1 x 10(6). These functional polyimides showed attractive potential applications in the field of high-performance flexible polymer photoconducting devices or polymer memory devices.