Study of PANI Preparation and Properties in Gas Sensing

In the paper, We can prepare the PANI in different conditions of acid (HCl, HNO₃, H₂SO₄ and C₇H₆O₆S · 2H₂O) by using aniline monomercc chemical oxidative polymerization. With the test of scanning electron microscopy (SEM), it shows that the powder of preparation is nanoscale particles, and the size of particle is in the order of tens to hundreds of nanometers. It has good dispersion, but the particle size is nonuniform, With differential thermo gravimetric analyzer (DTA) test, we can obtain the properties of powder in temperature of thermal decomposition and stability. At the room temperature, we test the sensitivity of gas for the ammonia concentration range of 1-7ppm. The result shows that, in different conditions of acids (HCl, HNO₃, H₂SO₄ and C₇H₆O₆S · 2H₂O), the relationship of sensitivity of gas sensor is linear in response to ammonia gas. With the analysis of the sensitive mechanism for ammonia gas of PANI material, ultimately, we can concluded that, in different conditions of acid, doped PANI materials are suitable to be detected for ammonia in a wide concentration range, the recovery time of response to ammonia gas is shorter and more stabile for the larger organo functional proton acid (C₇H₆O₆S · 2H₂O).