Synthesis of poly(diphenylamine) nanotubes in the channels of MCM-41 through self-assembly

We synthesized nanotubular poly(diphenylamine) (PDPA) by confining PDPA in the channels of MCM-41 (with a possibility of tuning the pore size). A two-stage synthesis, comprised of adsorption of diphenylamine (DPA) in the channels of MCM and subsequent oxidative polymerization to form PDPA, was employed. Adsorption of monomer was done in two different media, sulfuric acid (SA) and beta-naphthalene sulfonic acid (NSA). DPA molecules form self-assembly with NSA inside the pores of MCM-41. Polymerization proceeds differently in these two selected media. NSA provides an environment for the formation nanotubular PDPA inside the pores of MCM-41. Results from nitrogen adsorption-desorption measurements, X-ray diffraction analysis, scanning electron microscopy, FTIR spectroscopy, and thermogravimetric analysis show the presence of PDPA in the channels of MCM-41. PDPA formed inside the pores of MCM-41 was also removed from the pores. Field emission transmission microscopy of PDPA extracted from the pores reveals the nanotubular morphology. FTIR spectroscopy, proton NMR spectroscopy, and conductivity measurement were used to characterize the nanotubular PDPA. The electronic state of nanotubular PDPA shows the confinement effect from MCM-41 that is different from PDPA formed by the conventional method.