Synthesis, characterization and physicochemical studies of copolymers of aniline and 3-nitroaniline

Polyaniline (PA), the versatile conducting polymer, owing to its tunable optoelectronic properties, facile preparation methodology and reversible redox behavior, has elicited much interest among current researchers, particularly in the fields of energy generation storage devices, protective coatings and electrochemical sensors. However, its commercialization has been much restricted due to low solution processability and thermal stability. Recent studies reveal that the above-mentioned challenges can effectively be addressed by copolymerization of PA with suitable components. In addition, the properties of copolymers could be modified and tuned by varying the monomer ratios. Thus, the present work is concerned with the fabrication of poly(aniline-co-3-nitroaniline) with varying compositions obtained by in situ oxidative copolymerization of aniline and 3-nitroaniline by altering the molar ratio of monomers. Optimization of the physicochemical properties such as UV–visible absorption, solubility, thermal stability, electrical conductivity and dielectric signatures, particle size and morphology was achieved by varying the composition of monomeric substituents in these copolymers. Smoother morphology of the copolymer films was revealed by morphological studies via AFM technique and supported by particle size distribution study. The physicochemical trends demonstrated that proper proportions of nitro (–NO) group in the polymer chain are essential to achieve desired optimal physicochemical properties. Therefore, copolymers are ideally appropriate for multifaceted applications and would promote wider usage of conjugated polymers in various fields of organic-based optoelectronic as well as energy storage devices in the near future.