Optical and electrical investigation of the electrospun poly(N-vinyl carbazole) fibers

Fibers of polystyrene/poly(N-vinylcarbazole) (PS/PNVCz) were prepared by electrospinning method and cross polymerized (PS/c-PNVCz) by ring polymerization with ceric ammonium nitrate (CAN) to be used as free stand electrode. Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM) and polarized optical microscope (POM) were used for their structural characterization. Thermal stability and glass transition temperature (T_g) were measured by differential scanning calorimetry (DSC). The synthesis and characterization results showed that the incorporation of NVCz moieties affected the thermal characteristics with an increase in T_g, the topological properties of the PS fibers with an increase in fiber diameter and the crystallinity because of the π-π interaction between the stacking PNVCz rings and the PS. The interaction among the PNVCz chains with the electrolyte was discussed depending on the synthetic conditions, preparation process and the structure of the organic matrix according to the electrochemical impedance spectroscopy measurement results. The electrical conductivity of the PNVCz fibers was improved from semi-insulator (0.2×10⁻⁶ S·cm⁻¹) to semi-conducting (0.8×10⁻⁴ S·cm⁻¹) character. The measured fluorescence spectrums visualized the fibers dependency by a shift of the excitation from 328 nm to 358 nm with the PNVCz content.