Studies of the vapor-induced sensitivity of hybrid composites fabricated by filling polystyrene with carbon black and carbon nanofibers

A conductive composite with good gas sensitivity was fabricated by filling polystyrene (PS) with hybrid fillers composed of vapor grown carbon nanofiber (VGCNF) and carbon black (CB) introduced by solution mixing. The composite's electrical and gas sensitive properties were tested. The combined effect of the VGCNF and CB enormously ameliorated the conductivity of the hybrid composites due to the formation of special conductive pathways in the matrix. The composite obtained showed good gas sensitivity in many organic vapors. The sensitivity was affected by the total amount and the ratio of VGCNF to CB in the matrix, and also by the thickness of the composite's film. The gas sensitivity, upon exposure to vapors, of the composites containing the hybrid fillers is greater and more stable than that of the composites filled only with CB in vapors. These hybrid composites are very promising gas sensing materials and they can be used to make sensors to detect and discriminate many organic vapors. (c) 2006 Elsevier Ltd. All rights reserved.