Polar gas detector with probe surface of charged dielectric material - with low water absorption and high vol. resistivity to give high sensitivity

摘要

Probe for the detection of gaseous prods. (I) in the air has a surface of dielectric material (II), to which an electric charge, developing an electric field increasing the charge, is applied. (II) has a vole. resistivity of over 1 x 1012 ohm. cm at 50% RH and a water absorption capacity of under 1 wt.% at 95%RH. The surface of (II) has a surface energy component traced back to dispersion binding forces, a min. fraction stemming from the dipole H bonding forces. It reacts with (I) and yields a measurable electric output signal. The detector has much greater sensitivity than usual towards gaseous and particulate (polar) materials produced by combustion and present in the air.