Combined polymer sensitive elements for gas sensors

Abstract

The gas-sensitive combined polymeric active elements for optical gas sensors based on the mixture of polyortotoluidine (PoT) and polyorthoanisidine (PoA) have been developed and the change of their optical properties under the action of ammonia, hydrogen sulfide, and carbon dioxide has been investigated. It was found that in the thin films based on the mixture of PoT and PoA the changes in the optical absorption in the visible and near infrared regions of the spectrum under the action of these gases significantly increase in comparison with the individual components, and this increases the active elements sensitivity of the gas sensors based on them. It is shown that the presence and position of the isobestic point in the absorption spectra of the polymer films depend on their chemical composition and can be effectively controlled to ensure the selectivity of the optical gas sensors.