Exploitation of SnO2/Polypyrrole Interface for Detection of Ammonia Vapors Using Conductometric and Optical Techniques: A Theoretical and Experimental Analysis.

This study describes the construction of a lab-built Surface Plasmon Resonance (SPR) system for gas sensing applications employing a highly sensitive and trustworthy optical approach. The nanocomposite thin film of tin oxide (SnO2) and Polypyrrole (PPy) were prepared for sensing highly toxic gas, i.e., ammonia (NH3) gas. The gas sensor was validated by both optical and conductometric techniques of gas sensing. The optical SPR gas sensor is based on the change in refractive index at the SnO2/Polypyrrole (PPy) interface with gas adsorption (NH3). The thickness of SnO2 and Polypyrrole thin films was optimised using theoretical calculations for a sharp SPR reflectance curve. The manuscript also offers theoretical SPR curves for different PPy and SnO2 layer thicknesses. To support the theoretical conclusions, the effects of NH3 gas on the prism/Au/SnO2/Polypyrrole system were also investigated experimentally. In comparison to other research described in the literature, it was observed that the constructed sensor's sensitivity was higher. The obtained results demonstrate the utility of the SPR setup in the investigation of the interactions of adhered gas molecules with dielectrics and gas sensing. For conductometric gas sensing studies, the film having optimised thicknesses for sharp SPR reflectance curves was separately prepared on Interdigitated Electrodes. At a low working temperature of roughly 150 °C, the sensing response of the constructed film was observed and found to be maximal (60).

Contemporary nanocellulose-composites: A new paradigm for sensing applications.

Nanocellulose (NC) is the biological polymeric nanomaterial booming in the international market. The burgeoning demand for cellulose materials and advancements in nanotechnology have intensified the researches on the development of cellulose-based nanomaterials. Substantial research on nanocellulose-based composites in energy, electronics, biomedical, health, and the environment has been carried out in the last few decades. NC offers a plethora of outstanding properties such as biodegradability, renewability, and excellent fibrous structure. The recent advancement in the synthetic methodologies for various types of nanocellulose materials and their applications in a myriad of fields such as biosensing, chemical sensing, gas sensing, and strain sensing have been explored. The surface modification ability and robust nature of NC offer various possibilities for hybrid materials in the sensing field. Many sensors developed on plastic, paper, and glass platforms will be replaced with NC to modify the conventional sensing probes in the near future.