Preparation of nonwoven mats of electrospun poly(lactic acid)/polyaniline blend nanofibers: A new approach

The preparation of nonwoven mats of electrospun poly(lactic acid)/polyaniline (PANI) blend nanofibers faces some critical challenges that will be addressed in the present work. The challenges are in achieving high and adjustable content of PANI while keeping the spinnable solution nonagglomerated with no need to further filtration that might lead to wrong estimation of PANI content in the mat. We report an unprecedented content of 40% wt of PANI that is achieved using a new two-step procedure. It is based on: (1) the preparation of the spinnable solution from a friable nonagglomerated and readily dispersible PANI: p-TSA powder and (2) the use of an optimized mixture of m-cresol/dichloromethane. The obtained nanofiber mats are characterized by FTIR and UV-vis spectroscopy. The morphology and the thermal stability of the nanofibers are investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The amorphous structure of the nanofibers is verified using XRD measurements. The DC-conductivity of these blend nanofibers is found to be far larger than the published DC-conductivity values for blend nanofibers of PANI with PLLA or with other polymers. This is attributed to the high content of PANI in the blend and to the role played by m-cresol as a secondary dopant. The investigation of the aging effect on the DC-conductivity reveals an exponential decrease with a characteristic time of approximate to 13 weeks. The electrical impedance spectroscopy (EIS) shows a pure ohmic behavior of the blend mat. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43687.