Aggregates of reaction intermediates form during the early stages of aniline oxidative polymerization whenever the initial mole ratio of proton concentration to aniline monomer concentration is low ([H(+)](0)/[An](0)

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A low‐temperature method for the preparation of colloidal suspensions of bismuth telluride and selenide is presented. The method is based on Li intercalation, which can be followed by exfoliation and eventually restacking, thus leading to layered structures (see Figure and cover). The process and its parameters and characteristics are discussed in this work.

Formation of detectable intermediate aggregates is found to affect the morphologies of PANI nanomaterials, leading to either tubular or rod structures with striated growth and rough surfaces. By simply varying the ratio of initial proton and aniline concentration, a wide range of product morphologies can be synthesized. The intermediates form visible aggregates that can be separated by centrifugation or filtration. In addition to UV‐Vis monitoring of the intermediate aggregates, OCP and pH measurements are used to monitor the reaction process. GPC measurements show that the corresponding final products formed typically are not homogeneous. The correlation of intermediates formation and aggregation with product morphology suggests a route to controlled synthesis of PANI nanomaterials.magnified image

Nanomaterials made from the conducting polymer polyaniline (PANI) have very unique applications due to their high surface area and ease of processing. The link between synthesis conditions and morphology of PANI nanomaterials has been the subject of numerous investigations in recent years. Formation mechanisms for different morphologies have also been proposed. In this work, we report a self‐assembly method to make high yield PANI nanotubes with rectangular holes and outer contours by qualitatively and purposely controlling reaction rate. We find that aggregation of detectable and separable reaction intermediates is directly correlated with PANI nanotubes formation, consistent with the observation of oligoaniline precipitates reported in the literature. Control over intermediate aggregates morphology is studied systematically. By controlling the reaction rate through adjusting acid and oxidant concentrations, we can slow down the aggregation rate of the intermediates to largely enhance the yield of nanotubes with rectangular cross‐sections. To understand the correlation between the intermediates aggregation and the morphology of the resulting PANI tubes, the morphologies of intermediate aggregates and final nanotubes were characterized using SEM, STEM, and TEM. Open circuit potential (OCP) was used to monitor the polymerization process. Molecular weight distribution results were also obtained for the intermediate aggregates and the final products. Based on our study, we propose a simple PANI nanotube formation mechanism.