Carbon black filled poly(2-ethylhexyl methacrylate) as a candidate for gas sensing material

摘要

Carbon black/polymer composite vapor sensors have attracted significant attention for use in organic solvent vapor detection [1-5] because of the advantages like good response and reproducibility, wide responser range of chemicals and concentrations, fabrication with simple and economical design, etc. These conductive polymer composites function as sensors on the basis of the change of their electrical properties upon exposure to the sensing environment. That is, there is a drastic rise in resistivity when the materials meet certain solvent vapors. The mechanism involved has been described by the percolation theory. Sorption of an odorant into the insulating polymeric phase of the composites swells the sensing materials and produces a characteristic increase in the electrical resistance of the composites due to a decrease in the volume fraction of the conductive filter[6].