Polyaniline as a Gas-Sensor Material

Polyaniline (PANI) was synthesized by oxidative polymerization of aniline using ammonium persulfate in an acid medium. The polyaniline salt was converted to base form by treatment with ammonium hydroxide. The polyaniline base was dissolved in N-methyl pyrrolidone (NMP) for film casting. The cast film was doped with HCl for obtaining higher conductivity. Both doped and undoped PANI films were characterized by UV-visible, FTIR, and XRD analyses. The electrical conductivity of the PANI film was studied by a four-point probe method at room temperature. Finally, ammonia gas-sensing characteristics of the prepared polyaniline film were studied by measuring the change in electrical conductivity on exposure to ammonia gas at different concentrations. The influence of concentration of acid during polymerization of aniline and dopant concentration on the gas sensing characteristics of PANI film are reported in this paper.     

Coralloid SnO2 with hierarchical structure and their application as recoverable gas sensors for the detection of benzaldehyde/acetone

In this paper, we report a solvothermal route to fabricate coralloid hierarchical SnO₂ nanostructures. We obtain the product with different surface morphology at different reaction temperature. The breadth and length of the shot rod on the surface change with the temperature. A possible growth mechanism governing the formation of the nanostructures is discussed. Gas sensors based on the as-prepared SnO₂ nanostructures exhibit high sensitivity, short recovery time, good reproducibility and linear dependence relation to benzaldehyde/acetone, which is significant for exploiting gas-sensing materials in the future.     

气敏元件多功能测试系统

介绍了气敏元件多功能测试系统的工作原理及功能，并对其在气敏元件生产及研究的应用进行了介绍．     

The synthesis of asymmetrically substituted amphiphilic phthalocyanines and their gas-sensing properties

A series of asymmetrically substituted amphiphilic phthalocyanines have been synthesized. They have been deposited as Langmuir–Blodgett films onto glass and/or glass substrates bearing aluminum interdigitated electrode patterns. The films show fast response to NO₂ with almost complete recovery at room temperature. It is indicated that layer ordering and molecular packing within the LB films are important factors determined the gas-sensing properties.