Electrospinning of conducting polymer blend and composite nanofibers for sensor applications

Abstract

Study of electrospinning of polymer nanofibers for this project has spread into three areas: investigation of the electrospinning process, electrical properties of Polyethylene oxide (PEO)/carbon black nanofibers, and PMMA/PANi(AMPS) for alcohol sensing. In order to optimize the fiber size and suppress the bead formation, different electrospinning conditions and solutions of PMMA have been investigated. Highly aligned electrospun nanofibers have been made successfully by using a high speed rotating collector with the surface velocity beyond 6 ms⁻¹. On the other hand, aligned PEO/carbon black nanofibers has been electrospun. Characterization of the fibers has been done by using SEM, TEM and FTIR. As revealed by the polarized FTIR, the nanofibers produced are mainly in trans configuration where the helix structure were suppressed. With the present of carbon black inclusion, the conductivity of PEO nanofibers decreases significantly. This indicates that the conducting phase of the electrospun composite nanofibers would not help to raise the conductivity of the composite fiber, which is contrary to the conventional concept. Lastly, the study of PMMA/PANi(AMPS) nanofibers is performed, which is aimed to investigate the nanofibers response with respect to various alcohol molecules: such as the methanol, ethanol and isopropanol, respectively. The electrical conduction of the samples respond to various concentrations of alcohol and their repeatability of the signals were studied, and two mechanisms that responsible to the resistance change are suggested. As the PANi is the essential component responsible to the alcohol sensing but it will also hinder the formation of fiber forming in the electrospinning process, an optimum fraction of the PANi has been determined in this part of investigation.