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We report on the synthesis of an electrically conductive chitosan nanofibrous scaffold (NFS) by a “simple template free self-assembly method” from biopolymer chitosan in the presence of inorganic acids as dopants and ammonium persulphate (APS) as an initiator. The morphology of the chitosan nanofibers scaffold (CS-NFS) was examined by field emission scanning electron microscopy (FE-SEM). Physiochemical characterizations of the CSNFS were analyzed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. It is found that the morphology and structure of the CS-NFS strongly depend on the kinds of dopant used. Cyclic voltammogram measurement reveals that CS nanofibers have high electrocatalytic activity compared to chitosan powder. The CS nanofibers are expected to be useful in electrical, optical, and electrochemical devices. Open image in new window

A modified electrode was fabricated by grafting poly(2,5-dimethoxyaniline) (PDMA) onto multiwalled carbon nanotubes (MWNTs) and used for the electrocatalytic oxidation of ascorbic acid (AA). Cyclic voltammetry was used to fabricate the modified electrode and demonstrate the electroactivity of MWNT-g-PDMA-ME towards AA. Field emission scanning electron microscopy (FESEM) of MWNT-g-PDMA-ME revealed the combined presence of MWNT and PDMA. The MWNT-g-PDMA-ME exhibited excellent performance for AA at 320 mV with a high sensitivity (12.78 μA/mM) and linear concentration range of 1 to 5 mM (correlation coefficient of 0.9991). Differential pulse voltammetry (DPVs) showed that MWNT-g-PDMA-ME experiences negligible interference from other electro-active components.

Conducting hybrid submicrostructures composed of chitosan (CS and silica-based conducting poly[N-(3-trimethoxysilylpropyl)aniline] (PTMSPA were prepared by graft copolymerization. The spherical and fibrous morphologies of the CS-PTMSPA hybrid submicrostructures could be observed by optical and field emission electron microscopy. Under room temperature conditions, the CS-PTMSPA graft copolymers possessed the uniformly distributed spherical submicroparticles with diameters in the range of ca. 400–1,000 nm. On the other hand, under ice cold conditions (5 °C), CS-PTMSPA showed the development of randomly oriented fiber bundles. The diameter of a single fiber was in the range of ca. 100–500 nm. These CS-PTMSPA fibers were obtained by a temperature-driven template-free self-assembly pathway. Spectroscopic and thermal evaluations confirmed that CS-PTMSPA graft copolymer had been prepared by an oxidative polymerization method. The electrochemical performance of the CS-PTMSPA submicrostructures were compared with CS and PTMSPA by cyclic voltammetry with the Fe(CN)63−/4− system as a redox marker. The CS-PTMSPA submicrostructures showed high electrical conductivity (difference between the anodic and cathodic peaks = 0.24 and 0.29 V for CS-PTMSPA sphere and fiber, respectively compared to those of CS (0.14 V and PTMSPA (0.20 V), which was ascribed to the relatively high surface-to-volume ratios of these submicrostructures. Open image in new window