Abstract:
Various morphologies of polyaniline (PANI) nanoparticles, including nanofibrils, dendrites, and spheres, were synthesized by oxidative polymerization of aniline in the presence of different types of templates those are chlorophyllin, carboxymethly chitin (CM-chitin), and partially cross-linked carboxymethyl chitin, respectively. The pristine PANI anaoparticles are obtained after removing the templates by simply washing with specific solvents. Contrary, irregularly-shaped aggregates with a diameter greater than 1 um are obtained by using the conventional method (without the addition of templates). Molecular characterizations (including UV-vis, FTIR, TGA, and XRD) suggest an identical structure between PANI synthesized with and without templates. The morphology and size of the synthesized PANI products are also dependent on various parameters, e.g. structure of the template materials, the ratio of monomer to template, and synthetic conditions. CM-chitin template can be applied to synthesize a spherical shape of polypyrrole (PPY) nanoparticles as well. In a preparation of nanocomposite films, it is further explored that the synthesized PPY nanoparticles are better dispersed in the CM-chitin matrix than that of the conventional particles. Rheological measurements indicate that the addition of PPY nanoparticles can decrease the viscosity of alginate. In contrast, the increase of suspension viscosity is observed when adding the larger size of conventional PPY in alginate. The distince rheological behaviours are influenced by the size of PPY nanoparticles as well as the electronic state of PPY nanoparticles.
