Electrochemical Synthesis And Properties Of Poly(aniline-co-4-aminosalicylic Acid)

In recent years,conductive polymer materials have been developed rapidly and applied widely in a variety of areas,including stealth devices,batteries,sensors and display devices.Polyaniline is one of the most promising and widely used conductive polymer materials,but these applications are limited due to that its electroactivity depends highly on pH.4-Aminosalicylic acid is an aniline derivative,but it has acidic and redox-active groups.Herein,4-Aminosalicylic acid was chosen to synthesize its homopolymer and copolymer by cyclic voltammetry,and then the electrochemical activities of the resulting polymers were studied.Furthermore,the poly(aniline-co-4-aminosalicylic acid)was used as an electrode material for electrochemical sensors and batteries.In addition,for a comparison,4-aminosalicylic acid and aniline were electropolymerized individually in detail here.The electrochemical copolymerization method has significant reference value to explore and study more new conductive polymer materials with acidic and redox-active groups and their applications.1.Electrochemical synthesis and properties of poly(4-aminosalicylic acid)Poly(4-aminosalicylic acid)was synthesized on a glassy carbon electrode using cyclic voltammetry.The resultant polymer shows a good electrochemical activity in 0.30 mol·L-1 Na2SO4 solutions of pH 1.0–12.0.This is mainly due to the synergistic effect of the –COOH and –OH functional groups in the polymer chain.The oxidation and reduction peak currents of the polymer are linearly related to the square root of the scanning rate,respectively,indicating that the electrode reaction is controlled by the diffusion process.Based on the UV-Vis,FT-IR,XPS and NMR spectra of its polymer,the polymerization mechanism of 4-aminosalicylic acid was proposed.SEM result shows that the morphology of the polymer is mainly composed of dispersed particles.2.Electrochemical synthesis and properties of poly(aniline-co-4-aminosalicylic acid)Poly(aniline-co-4-aminosalicylic acid)was synthesized on a glassy carbon electrode via cyclic voltammetry.The resultant copolymer shows a high electrochemical activity in 0.30 mol·L-1 Na2SO4 solution of pH 1.0–11.0.This is mainly due to the –COOH and –OH functional groups of 4-aminosalicylic acid unit of the copolymer chains,which can adjust the pH of the copolymer surrounding environment.The results of UV-Vis,FT-IR and XPS spectra show that 4-aminosalicylic acid has been successfully introduced into the copolymer chains after copolymerization.SEM results show that the copolymer nanostructures composed of interwoven fibrous rods with small particles are significantly affected by the monomer concentration and the applied cyclic potential range,especially upper potential limit.3.Hydrogen peroxide sensor based on poly(aniline-co-4-aminosalicylic acid)Poly(aniline-co-4-aminosalicylic acid)was synthesized on a glassy carbon electrode by cyclic voltammetry,and was used as a novel enzyme-free hydrogen peroxide sensor.Cyclic voltammetry shows that the copolymer modified electrode can effectively catalyze the reduction of H2O2.Therefore,this copolymer electrode can be used to determine H2O2.Chronoamperometry shows that a linear correlation coefficient of 0.9969 was obtained in the range of 5–500 ?mol·L-1 in a pH 6.0 phosphate buffer solution containing H2O2.In addition,the copolymer electrode has good selectivity and stability.4.Electrochemical properties of poly(aniline-co-4-aminosalicylic acid)for Zinc-conductive polymer rechargeable batteriesNanowired poly(aniline-co-4-aminosalicylic acid)was synthesized on a platinum electrode by cyclic voltammetry.SEM results exhibit that the copolymer nanowires are 20–80 nm in diameter.Based on the cyclic voltammograms and impedance spectra of the copolymer in ZnCl2/NH4 Cl solutions,the poly(aniline-co-4-aminosalicylic acid)electrode was used as a positive electrode,a zinc sheet as a negative electrode,and the NH4Cl/ZnCl2 mixture solution as an electrolyte for a Zn-polymer secondary battery.The discharge and charge performance of the battery was measured by chronopotentiometry.Results show that the specific capacity of the copolymer battery is much higher than that of polyaniline battery.At the 181 st charge-discharge cycle,the coulomb efficiency of 97.9% indicates that the aqueous Zn-copolymer secondary battery has a good charge and discharge performance.