Controlled polymerization of aniline against templating oxide nanostructures

Article Controlled Polymerization of Aniline against Templating Oxide Nanostructures Matas Simukaitis 1, Grace Purnell 1, Zachary Zander 2, Danielle Kuhn 2 and Yugang Sun 1,* 1 Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, PA 19122, USA 2 U.S. Army DEVCOM Chemical Biological Center, Research & Technology Directorate, Aberdeen Proving Ground, MD 21010, USA * Correspondence: [email protected] Received: 6 November 2024; Revised: 30 November 2024; Accepted: 3 December 2024; Published: 4 December 2024 Abstract: Conducting polyaniline (PANI) nanotubes with strong broadband optical absorption have been synthesized using single-crystalline MnO2 nanotubes as a solid-state oxidant that can oxidize aniline to induce polymerization in acidic solutions. The smooth surfaces and high crystalline integrity of the MnO2 nanotubes provide the appropriate reactive solid/liquid interface and templating effect to enable the transformation of the MnO2 nanotubes into PANI nanotubes. Such templated chemical transformation can be extended to silica-coated MnO2 nanotubes, allowing the synthesis of silica-coated PANI nanotubes, which are challenging to be synthesized through direct coating silica on PANI nanotubes due to the low wettability between PANI and silica. The versatile chemistry of the outer silica shells opens the possibility of modifying the as-synthesized PANI nanotubes, which usually inconveniently graft other interesting motifs.