Direct synthesis of SILVER nanoparticles and polyaniline into the MESOPORES of SBA-15

The uniform structural pores architecture in nanoscopic domain of ordered mesoporous silicas, such as MCM-41 and SBA-15, can be used as a confined space to produce nanomaterials with controlled dimensions and cylindrical shape. In this study, we report the synthesis of a ternary nanocomposite constituted of silver nanoparticles and polyaniline concomitantly produced in the presence of SBA-15. The synthetic process involved firstly the adsorption of aniline vapor into the silica pores followed by its polymerization by reacting with the silver salt (AgN(SO2CF3)2) solubilized in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (BMImTf2N). With this synthetic approach the reaction proceeded quickly and efficiently, generating the silver-polyaniline nanocomposite mainly into pores and without collapsing the silica mesostructure. Surface area and pore volume of SBA-15 decreased after the reaction proceeded, indicating the formation of polyaniline and silver nanoparticles composite inside the pores and complementary analysis evidenced the presence of some silver nanoparticles outside pores. The measured electrical conductivity of the ternary composite in the order of 10−6 S cm−1 was coherent to the presence of the polymer and silver nanoparticles inside the pores of the insulator SBA-15 mesostructure rather than on the surface of the particles. The prepared SBA-15 ternary nanocomposite presented higher silver nanoparticles loadings of and superior surface area than the ones observed to small pore silicas, such MCM-41. The improvement in textural properties of the nanocomposite are favorable aspects for the further development of sensors and catalysts.