Development of layer-by-layer CNT thin film assemblies for volatile organic compounds sensing

In this study carbon nanotubes (CNT)-based conductive polymer nanocomposites fabricated by electrostatic layerby-layer (LbL) technique were used as the sensitive gas sensors. The conductive layers were progressively built alternative exposing into sodium deoxycholate (DOC)stabilized CNT anionic and poly(diallyldimethyl-ammonium chloride) [PDDA] cationic solutions, respectively. By this technique the fine control of sensitivity to VOC was accomplished due to a fine tuning of multilayer films resistance (from 50 to 2 kΩ) by the precise control of layer thicknesses (from 5 to 40 nm). This study resulted that 16 bilayer PDDA/(CNT+DOC) LbL assemblies provided the optimum detecting and diagnosing performances of eight VOC vapors (i.e., chloroform, acetone, ethanol, water, toluene, dichloromethane, tetrahydrofuran and methanol).