Early stage pH profile: the key factor controlling the construction of polyaniline micro/nanostructures

During aniline chemical oxidative polymerization which accompanies a falling pH, the initial acidity as well as the early stage pH profile actually plays an important role in the formation of polyaniline (PANI) micro/nanostructures. By utilizing an interfacial polymerization system, transfer and dosage of the reactants were controlled to change acidity profile during the early stage of reaction, without introducing any extra electrolytes. The results showed that, even for the polymerization systems with identical conditions, significant increase on the early stage pH profile induced by accelerated reactants’ transfer had led to PANI exhibiting molecular structures and morphologies typically belonging to those synthesized with weak acidity. Effects of the early stage acidity profile on the final PANI products can be attributed to the initially formed oligomeric products, which can direct the self-assembly of subsequently produced polymers.