Gas-sensing characteristics of dielectrophoretically assembled composite film of oxygen plasma-treated SWCNTs and PEDOT/PSS polymer

摘要

The composite film with high gas sensing capability was synthesized through dielectrophoretic assem bly of nanostructured layer of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) matrix and O_2 plasma-treated single-walled carbon nanotubes (SWCNTs). Characterizations of the PEDOT/PSS-SWCNTs composite were carried out by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and field emitting scanning electron microscope (FE-SEM). The results showed that oxygen-containing functional groups were grafted on the SWCNTs surface by O_2 plasma treatment. The functionalized SWCNTs homogeneously dispersed in the PEDOT/PSS matrix by π-π interaction and electrostatic attraction between PEDOT chains and the nanotubes. The SWCNTs concentration affected the gas-sensing properties of the composite film via the induced morphological and conductive variation. The conductive and gas-sensing characteristics of the composite film were improved by aligning the functionalized-SWCNTs in the polymer and forming the nanostructured film surface using dielectrophoretic manipulation. The gas sensors based on the optimally dielectrophoresis-assembled composite film showed high sensitive, selective, rapid, stable and reversible responses for detection of 2-300 ppm NH_3 and 6-1000 ppb trimethylamine gases at room temperature, suggesting its potential for assessing fish freshness in the fishery chain.