Preparation And Properties Of Polyaniline Modified Electrodes And Their Infrared Electrochromic Devices

Aiming at the requirements of the infrared electrochromic devices and considering the dynamic changes in IR region of polyaniline, polyaniline-modified electrodes were prepared by potentiostatic and galvanostatic electropolymerization methods. The properties of surface morphology, structure and cyclic voltammetry of the electrodes were studied as functions of voltage, current and coulomb of electropolymerization. Infrared electrochromic devices were fabricated by using the polyaniline-modified electrodes as the working electrodes. Infrared electrochromism, switching time and cycle properties of the devices were studied as functions of the different fabrication conditions of the polyaniline-modified electrodes.The studies of the polyaniline-modified electrodes show that there exists great difference between the polyaniline-modified electrodes fabricated by different electropolymerization methods. Polyaniline films which were fabricated by potentiostatic electropolymerization method have multi-structure, compact degree, oxidation degree and doping degree of each structure are different. The oxidation degree of the compact inner structure of the polyaniline films are decrease as the voltage of electropolymerization raise, and the oxidation degree of the polyaniline films are decrease as the coulomb of electropolymerization is increase. The polyaniline films which were fabricated by potentiostatic electropolymerization method only have mono-structure. When the current of electropolymerization raise, the oxidation degree of polyaniline films have a little increase. The oxidation degree of the polyaniline films are decrease and the doping degree of the polyaniline films are increase as the coulomb of electropolymerization is increase.The studies of the infrared electrochromic devices show that the emissivity vibration of the devices in the range of 8-12μm are according with the transmission mechanism. The thickness and the doping degree of the polyaniline films on the working electrodes have great influence on the emissivity of the infrared electrochromic devices. The emissivity of the devices raise as the thickness or the doping degree of the polyaniline films are increase. When the coulomb of electropolymerization of the polyaniline films on the working electrodes are 14C, the infrared electrochromic devices have great emissivity vibration. The infrared electrochromic devices which working electrodes were fabricated by potentiostatic method have an emissivity vibration among 0.43 to 0.9, and the infrared electrochromic devices which working electrodes were fabricated by galvanostatic method have an emissivity vibration among 0.33 to 0.79. The switching time of the devices are at second level and they keep unchanged as the fabrication conditions of the working electrodes changing. When the fabrication conditions such as voltage, current or the coulomb of electropolymerization raise, the cycle properties of the infrared electrochromic devices are getting worse.