Preparation and characterization of polyaniline-containing Na-AlMCM-41 as nanocomposite material with semiconductor behabior

ANUNZIATA, O.; MARCOS BRUNO GOMEZ COSTA; SÁNCHEZ, R.

JOURNAL OF COLLOID AND INTERFACE SCIENCE

ELSEVIER

Año: 2005 vol. 292 p. 509 - 516

0021-9797

PANI/MCM-41 composites by an in-situ polymerization technique have been synthesized. Studies of aniline adsorption over mesoporous MCM-41 synthesized in our laboratory, allowed us to find the modes that aniline interacts with the active sites of MCM-41. In order to obtain the best reaction conditions to polymerize aniline onto Na–AlMCM-41, aniline was first polymerized to produce pure PANI in solution. Hence, the oxidative in-situ polymerization was carried out by two procedures, differing in the polymerization time and in static or stirring conditions. Studies of Infrared spectroscopy and Uv-Vis spectroscopy indicated that higher polymerization time and static condition, allowed us to obtain mainly polyaniline in emeraldine form onto the host. The N2 isotherm of the PANI/MCM indicated that the shape was similar to MCM, but the shift to saturation transition to lower partial pressure shows that the channel are occupied by PANI and they are now narrowed. Conductivity studies shows that PANI/Na-AlMCM-41 exhibits semiconductor behavior at room temperature and its conductivity was 7.0x10-5 S cm-1, smaller than pure polyaniline. PANI/Na-AlMCM-41 conductivity shows an increase as temperature increases. Magnetization measurements at room temperature confirmed that the nanocomposite has paramagnetic behavior; at lower temperatures the composite became diamagnetic.