The Preparation And Humidity Sensing Of Composite Nanomaterials Based On Polyaniline

The nano-composites based on polyaniline were prepared, the morphology and structure of which were characterized. Electrochemical Impedance Spectroscopy (EIS) was employed to test the humidity sensing of composite materials.Polyaniline which possessed high conductivity and good humidity sensing was prepared, the synthesis method of which was discussed as well. The research about electrical characterization showed that the conductivity of polyaniline doped with sulfuric acid was highest, the humidity sensing of which was best. In the whole humidity area, it owned good linearity, small hysteresis. The increase of relative humidity had no effect on capacity of the sensor, but had great effect on the resistance of the solution and electron transferring, and they all decreased slowly.Copper and polyporrole nanowires were prepared by potentiostat and ac voltammetry with template of porous AAO, respectively. After dissolving the template, a great number of nanowires were obtained, the diameter and length of which were 70nm and 40～50μm, respectively. The nanoarray of copper and polyporrole were also prepared by dissolving the template partly, on which the polyaniline were insitu-polymerized. The composite materials were employed to make capacitive humidity sensor. The EIS showed that the resistance of sensor didn't change a lot, but the capacity of which increased with the increase of the relative humidity.Hydrothermal synthesis method was employed to prepare copper nanowires about millimeters long with the template of ODA. The composite materials were obtained by polymerizing polyaniline on the surface of copper nanowires with different quality, which was used to make resistant humidity sensor. The EIS showed that the resistance of the solution and charge transferring all decreased with the increase of relative humidity and decreased with the increase of content of copper nanowires with the same relative humidity.Humidity sensing materials were obtained by coating polyaniline on the surface of meso-tin oxide. Resistant humidity sensor was made by meso-tin oxide prepared by method of precipitation and double soft template, respectively. The EIS showed that the resistance of solution, charge transferring and charge diffuseness in film all decreased with the increase of relative humidity. With the same relative humidity, the resistance of sensor with mesoporous tin oxide made by double soft template was smaller, the sensitivity of which was higher. The polyaniline was polymerized on mesoporous tin oxide with different proportion, which made up of resistant humidity sensor. The resistance of sensor decreased with the increase of content of tin oxide with the same relative humidity and smaller composed of tin oxide made by double soft template.