Conducting polyaniline nanorods doped with aromatic carboxyl chain end functionalized polystyrene

Abstract

The preparation of new conducting polyaniline (PANI) derivatives with different nanostructures is described. PANI derivatives doped with aromatic carboxyl chain end functionalized polystyrene derivatives of different number average molecular weights between 18×103 and 3×103g/mol were prepared to determine the effect of the structure and number average molecular weights of the aromatic carboxyl chain end functionalized polystyrene dopant on the morphology of the resultant doped polyaniline derivatives. The aromatic carboxyl chain end functionalized polystyrene derivatives of different number average molecular weights were prepared by atom transfer radical polymerization (ATRP) methods using α-bromo-p-toluic acid as the aromatic carboxyl functionalized initiator. The chemical oxidative polymerization of aniline with ammonium persulphate as oxidant in the presence of aromatic carboxyl chain end functionalized polystyrenes as the dopants affords PANI derivatives as nanorods and nanosheets. The use of polymeric acids as dopants in the chemical oxidative polymerization of aniline leads to improved morphological control, eliminates dopant volatility, retains the electrical conductivity and promotes the processibility of the final polymeric carboxylic acid doped polyaniline derivatives. Also, the chemical oxidative polymerization of aniline with ammonium persulphate as oxidant in the presence of α-bromo-p-toluic acid as the dopant affords doped PANI derivatives as hollow microspheres. Furthermore, heating of the PANI nanorods doped with aromatic carboxyl chain end functionalized polystyrene under nitrogen atmosphere above 800°C affords carbon nanorods and nanosheets. The aromatic carboxyl chain end functionalized polystyrenes and the different PANI derivatives were characterized by size exclusion chromatography, 1H NMR and 13C NMR spectrometry, FTIR spectroscopy, UV–Vis spectroscopy, non-aqueous titrations, scanning electron microscopy, thermogravimetric analyses, transmission electron microscopy, X-ray diffraction and electrical conductivity measurements.