Highly sensitive toluene vapor sensors using carbon black/amino-functional copolymer composites

Abstract

An amino-functional copolymer [N,N,-dimethyl-1,3-propanediamine (MCD)] developed in our laboratory was blended with carbon black (CB/MCD composite) and its electrical responses to toluene vapor at low concentrations were measured at 30°C. When exposed to 200 ppm of toluene vapor, the CB/MCD sensor responded at S = 0.04 (S was obtained by dividing the relative change in the resistance of the sensor upon exposure to toluene vapor by the baseline resistance), demonstrating its ability to detect toluene vapor at low concentrations. The response was affected by humidity in the atmosphere due to the hydrophilic nature of MCD film; however, the behavior was reproducible before and after exposure of the sensor to the humid atmosphere. In addition, in 10 consecutive sorbing/desorbing cycles, it was confirmed that the changes in the resistance of the CB/MCD sensor were reproducible. These favorable sensing characteristics were attributed to vapor sorption behavior arising from the glassy and loosely crosslinked nature of MCD and explained by the dual-sorption model. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Copyright © 2012 Wiley Periodicals, Inc.