Polymeric Nanofibriller Matrix on ITO Substrate for Flexible Chemical Sensing Applications

Abstract

The authors present here a facile electrochemical approach to synthesize Poly(Aniline) nanofibriller matrix on ITO coated PET substrate for development of wearable or embeddable sensors. Electrochemical parameters were optimized for even diametric synthesis and controlled length of Poly (Aniline)) nanofibers. A three – step chrono potentiometric deposition was found to be efficient for the synthesis of the matrix. Precise tuning of galvanic conditions during the synthesis process was highly effective and repetitive towards controlling the nucleation of Poly (Aniline) seeds on the substrate that serves as the basis of nanofibers with presumable diameter range. Charge conduction behaviour of the matrix was studied via Linear Sweep Voltammetry and a semiconducting nature was observed. The synthesized nanofibrillar sensor platforms were subjected to Scanning Electron Microscopy (SEM), UV-VIS Spectroscopy and FTIR spectroscopy for elucidation of morphological and structural aspects. The distribution of nanofibers network throughout the substrate was uniform and dendritic. Flexibility characteristics of the sensors were studied by bending the sensor to different radii and in-situ monitoring of resistance. The synthesized sensor platforms were subjected to NO2 sensing in chemiresistive mode under dynamic conditions to investigate the applicability of the same under real-time applications. Upon exposure to different concentrations of NO2, the devices exhibit a rapid response at concentrations as low as 1 ppm. The betterment in overall sensing behaviour in comparison to conventional thin film type sensors could be attributed to the one-dimensional structure of nanofibers leading to effective diffusion on analyte molecules and low scattering loss during charge transport. These flexible sensors can be interesting for novel mobile applications.