Chemistry and Biochemistry: Research Progress Vol. 10

Polyaniline is one of the most important conductive materials with various applications ranging from electronics to biomedical engineering. The versatility of PANI originates from its complex molecular structure, which consists of phenylene rings linked by chemically flexible nitrogen-containing groups. Recent advancements have shifted focus toward the fabrication of PANI-based nanostructures and inorganic and polymer nanocomposites.  The study aims to demonstrate a green method for producing Polyaniline (PANI) nanoparticles. This chapter presents an easy, straightforward method for preparing and characterising PANI nanoparticles. PANI nano-particles were prepared using the solid-state polymerisation method in the presence of different amounts of ammonium peroxydisulfate (APS) for the synthesis of PANI nano-particles. Different characterisation methods have been introduced as simple, easy-to-use characterisation techniques, along with the assignment of each spectroscopic test. Vibrational structure and electronic transitions were studied using FTIR and UV-Vis spectroscopic techniques. PANI nano-particles were formed in emeraldine salt form. The optical band gap (Eg) of PANI nanoparticles, calculated from UV-Vis spectra using the Tauc relation, was 4.45 eV and exhibited a size-dependent shift, decreasing with increasing particle size and increasing with decreasing size. This behaviour could be attributed to quantum confinement. The effect of concentration on the crystallinity index was studied using X-ray diffraction (XRD).