The Synthesis Of Anisotropic Polyaniline Film And Its Application

Polyaniline belongs to conductive polymers,and it has many advantages,such as multiple oxidation states,synthesizing easily,great conductivity,high specific capacitance,good stability,and doping/dedoping easily.So it can be wildely used in sensors,supercapacitors,solar cells,electrochromism and other important fields.Since polyaniline synthesized by traditional methods has low molecular weight,the polyaniline film has poor mechanical behaviour and low conductivity.Those drawbacks limit the application of polyaniline.High molecular weight polyaniline may offer high specific capacitance,high conductivity and good processability.In nature,different organisms which have anisotropic structrue have great performance,such as human muscles,artilage,plant stems and so on.In view of this,with combining stretch-induced orientation,we used high molecular weight polyaniline as raw material,utilized the advantages of high molecualr weight,the ?-? stacking and hydrogen bond interactions between polyaniline chains,so to construct the anisotropic polyaniline film without using template.Studying the details of its electrochemical performance,we also explored its application in the field of flexible supercapacitors and electrochromic device.The main research are as follows:1.Synthesizing the anisotropic polyaniline film which has good properties.Polyaniline was synthesizing by normal chemical oxdiation polymerization in low temperature.Lithium Chloride was additive to lower the freezing point and increase the water solubility of mid product.Product had high molecular weight(Mw:110,000).By deprotonating product and dissolving it in LiCl/NMP solution,we heated solution to get polyaniline gel,followed by stretching process under certain humidity.Finally,using acid doping the film to obtain an anisotropic polyaniline film.It had outstanding mechanical behaviours(24 MPa,21%in parallel direction of stretching),high elastic module(323 MPa),high conductivity(33 S cm-1),with 811 F g-1 in specific capacitance,129 W h kg-1 in energy density and 10.86 kW kg-1 in power density.These excellent properties made the anisotropic polyaniline film an ideal material for flexible supercapacitors and electrochromic.The all-solid-supercapacitor that was made by cellulose separator had 689 mF cm-2 areal specific capacitance in 10.67 mA cm-2.Using PVA/H2SO4/KI3 electrolyte as separator,we also fabricated ultra-thin flexible supercapacitor.The thickness was 69?m,and its volume capacitance was 312 F cm-3 at the current density of 0.24 A cm-32.Fabricating ITO-free electrochromic device.Lowering the thickness of film,the anisotropic polyaniline film had great mechanical behaviour(34.5 MPa,70%),excellent conductivity(47.62 S cm-1).It can realize multi-color changes(green,yellow-green,dark blue,black)under the three-electrode tests in the LiClO4/PC system,and excellent cycling performance(more than 2000 times).Using ordinary glass as the substrate,we fabricated ITO-free electrochromic device,and successfully completed the color changes from green,yellow-green to dark blue,with good cycling stability.Moreover,it can use H2SO4/PVA as electrolyte.Based on the above,the product cost decreased.Therefore,it had great future.