Poly(3-alkylthiophene)/CNT-based chemiresistive sensors for vapor detection of linear alkanes: Effect of polymer side chain length

In general, alkane vapors are difficult to detect due to their non-reactive nature at room temperature. Here, we show chemiresistive sensors made of carbon nanotubes (CNTs) noncovalently functionalized with three kinds of poly(3-alkylthiophene) (P3AT), namely, poly(3-butylthiophene) (P3BT), poly(3-octylthiophene-2,5-diyl) (P3OT) and poly(3-dodecylthiophene-2,5-diyl) (P3DT). We compared the responses of sensors composed of these materials to four linear alkanes, hexane, octane, decane and dodecane. The results show that sensors with CNTs functionalized with P3ATs that have alkyl side chains with length similar to the length of the analyte alkane produced a bigger response than the case in which the lengths are different. Based on this response trend, a sensor array was made, which can distinguish different sizes of linear alkane vapors. This work facilitates the future design of CNT-based sensor arrays for distinguishing analytes with similar physical and chemical properties. (C) 2017 Elsevier B.V. All rights reserved.