Synthesis of conductive polyimide via graft conductive polymer

Polyimide has been widely studied, especially in terms of electronic devices due to their high thermal resistance, excellent chemical resistance, dimensional stability and ease of fabrication. This research was studied to improve polyimide properties in terms of conductive and water soluble materials for applications in printed circuit board (PCB), electrochromic displays, organic light emitting diodes (OLEDs) and organic photovoltaic devices (OPVs). The experimental consisted of 4 parts. The first part was studied the preparation of conductive polyimide-graft-polyaniline. Polyimide copolymer molecules can be made conductive by cooperation of grafted polyaniline. The conductivities of polyimide copolymers were in the range of 2.96-16.20 S/cm, depended on the chain length of graft polyaniline. The thermal stability of the polyimides copolymer was higher than the nascent polyaniline. The second part was studied the synthesis of the high strength surface-conductive polyimide film via comparison with polyimide/polyaniline-g-polyimide composite film. The conductivities, thermal stabilities and mechanical properties of surface-conductive polyimides were higher than conductive polyimide composites. The third part was studied comparison on three conducting polymers (PEDOT, PANI, PPy) with two sulfonated poly(imide)s. PANI-SPAA1 had the highest conductivity of 7.74 S/cm, which was without heat treatment and secondary doping. PANI-SPAA2 had the highest conductivity of 1.47 S/cm, which was doped with 0.1 wt.% of DMF. For PPy systems, the result showed the similar trends to the PEDOT systems. The conductivities were increased after doped with a secondary dopant and annealed for a short time. However, PANI system showed the lower thermal stability than PEDOT and PPy systems. The forth part was studied the preparation of high conductivities conducting polymers (PEDOT-PSS, PEDOT-SPAA1 and PEDOT-SPAA2) by using new method for the polymerization (SPAA1, SPAA2). The new method (mechanical stirring) to synthesis PEDOT with sulfonated poly(amic acid) template was undertaken and caused less reaction time and more conductivity than our earlier systems (magnetic stirring). The conductivities of PEDOT-SPAAs could be further enhanced by using the new secondary dopants (Benzo-1,4-dioxan, imidazole and quinoxaline) and heat treatment.