Oxygen plasma functionalized PEDOT/PSS-SWCNTs thin film deposited by electrophoresis for gas sensing

In this paper, the oxygen plasma treated single-walled carbon nanotubes (SWCNTs) were combined with the poly (3,4-ethylenedioxythiophene)/poly (styrenesulfonate) (PEDOT/PSS) solution to prepare the PEDOT/PSS-SWCNTs composite. Effects of the SWCNTs concentration and the alternative current dielectrophoresis (AC-DEP) assembly of the hybrid film on conductive characteristics and gas sensing properties of the modified electrode were investigated. It was found that SWCNTs treated by oxygen plasma could stably and homogeneously disperse into the PEDOT/PSS matrix which acted as a conductive dispersant. With the concentration of SWCNTs increasing gradually in the range of 1-20 mg/mL, the resistance of the modified electrode normally decreased while its gas sensitivity varied. Compared with the common drop-coating, AC-DEP assembly could improve the conductivity and gas sensing properties of the composite film. The PEDOT/PSS-SWCNTs composite film with SWCNTs of 5 mg/mL and deposited by AC-DEP, allowed the as-modified electrode for the rapid and sensitive response to NH₃ gas with the concentration range of 2-20 ppm.