Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting film

摘要

Gas diffusion barrier system (I) in which the gas inlet channel of the sensor is fitted with a siloxane and/or polysiloxane solubility membrane which limits the diffusion/flow of gas into the sensor; the membrane in this system consists of polydimethylsiloxanes (II). Process for the prodn. of a solubility membrane-diffusion barrier (I), involving the application of liq. (II) to the supporting substrate material (III) by painting or dip-coating. USE/ADVANTAGE - The method provides very thin membranes with variable thickness (see above) which enable diffusion-limited operation of gas sensors; membranes based on (II) have good transport coeffts, for oxygen, CO, H2S, SO2 etc., combined with high chemical stability and long service life.