Investigation of fundamental molecular parameters of polyaniline films

The effects of fabrication process and solvent on the structure of polyanil ine (PANI) emeraldine base films and their intrinsic properties are examine d. Freestanding films of PANI base fabricated from N,N'-dimethyl propylene urea (DMPU) and N-methyl-2-pyrrolidone (NMP) solutions, by casting and spin -coating procedures and subsequently drawn to different draw ratios, are ex amined. X-ray diffraction studies show that the PANI films processed from D MPU solution have a noncrystalline structure, whereas the PANI films cast f rom NMP solution are partially crystalline. The crystal structure is in con formity with the orthorhombic unit cell (EB-II) reported earlier. However, the c parameter of the unit cell was found to be slightly lower than the li terature values. A near-infrared waveguide technique was used to determine the three-dimensional refractive indices of the processed and drawn PANI fi lms. The anisotropies developed by the different fabrication and deformatio n procedures were compared and found to differ. Coupling birefringence and quantitative infrared dichroism measurements yields the intrinsic birefring ence and transition moment angles of the infrared absorption bands of PANI. (C) 1999 John Wiley & Sons, Inc.