Electrical resistance response of carbon black filled amorphous polymer composite sensors to organic vapors at low vapor concentrations

Electrical resistance responses of amorphous polymer composites against various organic vapors at low concentrations are investigated by using polymerization-filling fabricated carbon black/poly(butyl methacrylate) (CB/PBMA) system as the model material. The experimental results indicate that the composites have high selectivity to various organic vapors at the same concentration. In addition, the electric resistance response of the composites against organic vapors takes place in step with their vapor adsorption procedure. It is demonstrated that uptake of solvent vapors in the matrix polymer guarantees the increase in a composite's resistance over a wide range of vapor concentration. According to these findings, the composites can be used as an organic vapor sensor to detect, quantify and discriminate various organic vapors. Unlike the case of saturated vapors, similarity between the solubility parameters of the matrix polymer and a solvent can no longer serve as a criterion to predict the response of the composite against the low concentration solvent gas. (C) 2004 Elsevier Ltd. All rights reserved.