Ammonia-sensitive Study Of Thin Film Preparaed By Polypyrrole And Its Composite Materials

Traditional gas sensor are only have sensibility at a high temperature,while we need which could be used at room temperature. Polypyrrole has asimple preparation process, good environmental stability, could replace thetraditional metal oxide gas sensitive material and detect NH3at roomtemperature.Doped polypyrrole was synthetised by using pyrrole as monomer andFeCl₃·6H₂O as oxidant,through Chemical oxidative polymerizationmethod.Preparaed polypyrrole gas sensor by changing monomer concentration,dosage of oxidant,coating layers, different acid doping process, polypyrrole/polyaniline mass ratio.Analyzed the structure of polypyrrole and polyaniline by Ramanspectroscopy and infrared spectroscopy; Researched surface morphologies ofpolypyrrole and polyaniline by scanning electron microscope (SEM); Studiedthermal performance of polypyrrole and polyaniline throughthermogravimetric (TG). Discuss gas ammonia-sensitivity of polypyrroleand its composite materials.The results show that: the acid doped polypyrrole has good conductivityand environmental stability.which could be used for gas sensor. Study ondifferent process for the preparation of polypyrrole gas sensitive elementshow that: when the pyrrole monomer concentration is0.1mol/L, acidconcentration is1mol/L, coating layer is4, gas sensor has good sensitivity.PTSA dopant has the best sensitivity, was7.694. Sensitivity of polypyrrolegas sensor decreased with decrease of ammonia concentration,in addition tothe DBSA,other doped PPy has sensitivity at low concentration ammonia (5ppm).Sensitivity polypyrrole and polyaniline composite materials alsodecreased significantl with the ammonia concentration decreased, and still hassensitivity at low concentrations (5ppm) of ammonia. The composite material has good environmental stability, after20days testing, can stillmaintain a relatively high sensitivity. When m (PPy): m (PANI)=0.6forgas sensing element, whose sensitivity was13.957.After20days testing,it'ssensitivity can still maintain7.896,was a ideal gas sensor.