Photoelectrical properties of polyaniline/polyimide complex thin film

Using pyromellitic dianhydride (PMDA) and bis(4-aminophenyl) ether (ODA) as monomer materials, the polyamic acid (PAA), a precursor of polyimide (PI), was synthesized. PAn was doped and modified with the polyamic acid by solution mixing method, and the modified PAn/PAA blend with good solubility and forming-film was obtained. Then uniform PAn/PI complex thin film with good forming-film and thermo-stabiliry can be prepared by solvent casting and followed by thermal imidization process at the temperature of 150°C-250°C for 60 min. Conductance experiments showed the surface conductivity of PAn/PI thin films can raise to 10^-5S from 10 ^-10S and change with the increase of the content of PAA. IR and UV-vis spectra showed that it has a chemical doping reaction between PAn and PAA during mixing, and the absorption of PAn/PI complex films in UV-vis region appears red shift and the peak shape becomes broad. The degenerate four-wave mixing experimental results showed that the third-order optical nonlinear susceptibility χ⁽³⁾ of PAn/PI thin films can be markedly enhanced and the maximum χ⁽³⁾ can reach 8.85×10^-10esu, which presents good third-order nonlinear property.