Nucleation of Polyaniline Microspheres and Interconnected Nanostructures from Strongly Coupled Micelle-like Systems

A mechanistic study on the nucleation of aggregates exhibiting a weak intermolecular coupling and high molecular mobility for major components, exampled by an entity of aniline and salicylic acid in the preparation of polyaniline microspheres (PANI-NS) and interconnected structures (PANI-NC), is explored by in situ 1H NMR experiments. Three different procedures, namely, hydration of the aniline–salicylic acid (SA) entity, removal of the extra charges to the surroundings, and sphere-to-rod transitions, afford the smooth nucleation of products in characteristic morphologies. At the beginning, water plays a fundamental role in attenuating the high chemical potential system by hydrating both the aniline–SA entity and the in situ formed protons in the reaction, and removing the latter to bulk water when the chemical potential increment from the in situ produced proton is at a low initially. The driving force for this process is the increased intermolecular distances between aniline and SA induced by the electr...