Novel flexible, freestanding and transparent organic/inorganic hybrid materials formed between polyaniline and polyphosphate gel

In this paper we report the synthesis and characterization of new polyaniline/polyphosphate hybrid materials. The synthetic approach involves a single-step procedure in which the polyphosphate inorganic host structure (arising from a sol-gel transition) develops first, providing a restricted environment in which the conducting polymer is entrapped within the gel network. Polyaniline was formed as the green, conducting emeraldine salt form. The samples were characterized by thermogravimetric analysis and UV-vis, Raman, EPR and P-31-MAS-NMR spectroscopies. We have synthesized homogeneous, flexible, freestanding and transparent materials in which the conducting polymer presents a coiled conformation typical of primary doped polyaniline. Upon exposition to ammonia vapors the polymer can be converted to the emeraldine base form, which can be reverted by exposition to HCl vapors. Powdered samples present dc conductivities up to 0.2 S cm(-1). (C) 2004 Elsevier B.V. All rights reserved.