Polyanthranilic acid (PANA) nanofibres, nanorods,
nanospheres and microspheres were synthesized by polymerization
of anthranilic acid using ammonium peroxydisulfate (APS)
as oxidant without hard or soft templates. Polymerization of
anthranilic acid was carried out in aqueous solutions of
strong (hydrochloric) and weak (acetic) acids. The influence
of synthetic parameters such as oxidant, initiator, dopant acid
and its concentration, redox initiator, and reaction medium on
the morphology and particle size of PANA have been investigated.
PANA nanofibres and nanorods were obtained via
redox polymerization of anthranilic acid initiated by FeSO4
as redox initiator. PANA nanospheres and nanofibres were
also obtained when used aromatic amines as initiators. When
polymerization carried out in the solution of weak (acetic) acid
the microsphere morphology obtained and the particle size
increase with increasing the concentration of weak acid.
PANA nanorods were obtained also by polymerization of
anthranilic in ethanol-water mixture unlike interfacial polymerization
of anthranilic acid (in chloroform-water) that give
PANA microspheres. The morphology and particle size of
PANA was studied by scanning electron microscope (SEM)
and transmission electron microscope (TEM). The average
diameter of nanostructures obtained ≤100 nm. The optical
bandgap of microspheres and nanofibers polymeric products
were determined using UV-vis spectroscopic technique and
found to be 2.0 eV and 1.6 eV, respectively. The bandgap
decreased with decreasing the particle size. IR spectrum confirmed
the structure of PANA nanofibres (synthesized with
FeSO4 as redox initiator) in emeraldine form. The thermal
stability of polymer obtained was determined by thermal
gravimetric analysis (TGA). The molecular weight was determined
also by gel permeation chromatography (GPC). |
