In-situ Chemical Synthesis of Polypyrrole/Silver Nanocomposite for the Use as a Room Temperature Ammonia Gas Sensor

Abstract

Two different types of polypyrrole/Ag nanocomposites were prepared by the use of in-situ chemical polymerization of pyrrole monomers in the presence of silver nitrate. Template-free and template-assisted methods were used to the preparation of polypyrrole nanosphere/Ag nanocomposite and polypyrrole fiber/Ag nanocomposite, respectively by the use of ammonium persulfate as oxidant and lithium perchlorate (LiClO4) as dopant agent. The materials were characterized using SEM imaging and EDS analysis. Thin films of prepared nanocomposites were spin coated on interdigitated electrodes to study the ammonia gas sensing property. It was found that ammonia gas sensing performance including sensitivity, response time, and recovery time of polypyrrole fiber/Ag nanocomposite sensor is better than that of polypyrrole nanosphere/Ag nanocomposite sensor. It was also revealed that polypyrrole fiber/Ag nanocomposite sensor was not saturated even in the presence of 250 ppm ammonia gas whereas polypyrrole nanosphere/Ag nanocomposite was saturated with 100 ppm ammonia gas concentration.