In this work, polyaniline nanowires and nanorods are synthesized through adjusting and controlling the concentration of D‐camphor‐10‐sulfonic acid (CSA) and NaF salt under the application of an electric field. The morphologies and structures of as‐synthesized polyaniline (PANI) are characterized through various methods, including transmission electron microscopy, UV–vis, Fouier transform infrared spectroscopy, and X‐ray diffraction. The results demonstrate that the introduction of an electric field can improve the crystallinity of PANI, and PANI nanowires/nanorods are fabricated through changing the amount of NaF or CSA in the presence of the electric field. Besides, the 1H NMR experiments are executed to investigate the structures of final products.

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Polyaniline/Zinc oxide (PANI/ZnO) were prepared using a two-step method, and the morphology and the structure of PANI/ZnO composites were characterized through a scanning electron microscope (SEM) and X-ray diffraction (XRD). Factors such as the content of ZnO, the adsorption time and the mass of the adsorbent, and the kinetic equation of PANI/ZnO as adsorbents for the adsorption of methyl orange solution were studied. The results showed that the adsorption efficiency of methyl orange by polyaniline with the increase of adsorbent mass firstly increased and then decreased. Among the composites with the same quality, PANI composites with 8% ZnO have a better adsorption effect for methyl orange, and the maximum adsorption ratio can reach 69% with the increase of adsorption time at 0.033 g; With the increase of adsorbent mass, the adsorption efficiency of PANI composites with 8% ZnO increased continuously. When the mass increased from 0.033 g to 0.132 g, the adsorption rate increased from 69% to 93%, and the adsorption of the methyl orange solution by PANI/ZnO composites was more in line with the quasi-second-order kinetic equation.

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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 electrostatic repulsions between positively charged protons in the entity, which paves the pathway for water in bulk to diffuse into the system. When a large amount of protons have been released in the reaction, the high chemical potential can be lowered down by repulsing both large and small sized positive charges to the external surroundings through electrostatic interactions or a sphere-to-rod structural transition initiated by continuously formed oligomers sheathed at the exterior of the spheres, which affords the formation of PANI-NS and PANI-NC, respectively. The competition of the two depends on the relative amplitude between the releasing rate of the protons and the mechanical strength of the aniline–SA entity in the reaction. Our work demonstrates that in situ dynamic NMR experiments such as measurements of NOE and spin–lattice relaxation times, and line shape analysis, provide new perspective powers for resolving the formation profile and more importantly the driving forces for each procedure at the molecular scale.