Ion-exchange and humidity sensing properties of poly-o-anisidine Sn(IV) arsenophosphate nano-composite cation-exchanger

In order to develop a new kind of humidity sensing material, the poly-o-anisidine nano-composite containing Sn(IV) arsenophosphate cation-exchanger was synthesized using by sol–gel method. Cation-exchange behaviors were studied in order to get the material suitable for its application as ion-exchanger. By studying ion exchange kinetics some of the physical parameters like self diffusion coefficient (D°), energy of activation (Ea) and standard entropy change (ΔS°) have been evaluated under conditions favoring a particle diffusion controlled mechanism. The humidity sensing response (adsorption) and recovery (desorption) time of the nano-composite was examined at room temperature (25 °C). It was observed that the electrical conductivity varied according to low humidity to high humidity increased from 10−4 to 10−1 S cm−1 when pressed pellets made from the synthetic nano-composite was exposed to the range of humidity level from 20% to 90%. The results indicated that in comparison with pristine poly-o-anisidine not only the morphology of nanocomposite was entirely changed, but its thermal stability as well as water vapour sensitivity was also improved appreciably by adding Sn(IV) arsenophosphate cation exchanger when incorporated in poly-o-anisidine.