| Polyaniline has become the most widely used polymer material due to its excellent electrical conductivity,unique doped and dedoped characteristics,outstanding pitting resistance,and excellent environmental sTableility.In this paper,the direct doping oxidation-reduction method is used to obtain the primary doped polyaniline products under different inorganic acid and organic acid systems.The best primary acid system is obtained by comparison of its morphology and properties.According to unique doping-dedoping characteristic,the redoping polyaniline can be obtained by using the redoped method.Through yield calculation,conductivity measurement and solubility measurement,the products can be characterized by scanning electron microscopy,four-probe conductivity meter,infrared spectrum and ultraviolet-visible spectrum.The polyaniline product was filmed on the working electrode.The electrochemical performance of the polyaniline product in different acid systems is tested by the Princeton P4000 electrochemical workstation.The test results have been fitted and the following main conclusions were obtained:1.With the direct mixed oxidation polymerization method,doping polyaniline nanofiber products can be prepared in different inorganic acid systems.Among them,the perchloric acid system has the best morphology,yield and conductivity are also the best,up to 110.11%and 0.101S/cm,respectly.The perchloric acid system has been used as a primary doping acid,ammonia has been used for dedoping,and the redoping has been performed with different inorganic acid systems.The product has improved more or less,it has a longer fiber length,larger aspect ratio,more regular appearance and more uniform dimensions than the primary product.And the yield and conductivity also increase in different ranges.It was proved that the redoping polyaniline improves the morphology and performance of the primary product in the inorganic acid system.The polyaniline nanomaterials have been obtained in different inorganic acid systems and products with excellent morphology often have excellent yields and electrical conductivities,indicating that the morphology of the polyaniline products has an effect on the performance of other aspects,which also provides new ideas for redoping polyaniline of nano-functional materials.2.With the direct mixed oxidation polymerization method,doped polyaniline nanofibers can be synthesized in different inorganic acid systems.Among them,the tartaric acid system has the best morphology;the yield and conductivity are the best,up to 104.68%and 0.0223S/cm,respectively.However,there is still a gap compared to the primary doping products of the perchloric acid system.Therefore,the perchloric acid system is still selected as a primary doping acid system.The perchloric acid system has been used as a primary doping acid,ammonia has been used for dedoping,and then different organic acid systems has been used for redoped acids.The product has improved more or less,it has a longer fiber length,larger aspect ratio,more regular appearance and more uniform dimensions than the primary product.The yield and electrical conductivity also increased in different ranges.It has been proved that the redoping method improves the morphology and performance of the primary product in the organic acid system.Individual(such as tannic acid,molybdic acid)organic acid system can lead to an unobtainable primary doping product due to poor solubility,through the redoping method,we can get the product with good morphology,excellent performance.This redoping method also opens new avenues for solving the doping acid systems with poor soluble properties.The polyaniline nanomaterials has been prepared in different organic acid systems have better The product that has been prepared in different organic acid systems usually has better morphology,yields and electrical conductivity,which could indicate that the morphology of the polyaniline can affect other aspects of performance and could also provides new ways for redoping polyaniline of nano-functional materials.3.The results of electrochemical polarization curve show that the corrosion potentials of polyaniline products in different acid systems have negative shifts to varying extents compared to bare steel corrosion potentials.This also indicates that the polyaniline products in different acid systems show different degree of corrosion resistance.Among them,the perchloric acid system has the best anticorrosion performance and the inhibition rate can reach 67.57%in the inorganic acid system.The tartaric acid system has the strongest anticorrosion ability and the corrosion inhibition rate reaches 62.36%in the organic acid system.The primary product of polyaniline not only has obtaining excellent appearance and electrical conductivity but also has the best anti-corrosion ability.Through electrochemical impedance spectroscopy analysis,it has been found that the impedance curve of polyaniline products in different acid systems has showed a different degree of increase than the resistance arc of bare steel,which indicate that the polyaniline products in different acid systems show corrosion ability with different levels.In the inorganic acid system,the perchloric acid system had the best anticorrosion performance and the impedance rate is up to 694.52?/cm~2.In the organic acid system,the tartaric acid system has the strongest corrosion resistance,and the impedance rate reaches 604.22?/cm~2.This also confirms that the primary product of polyaniline obtains the best corrosion resistance,its excellent appearance as well as electrical conductivity.In the polarization curve test and electrochemical impedance spectroscopy analysis,the corrosion potentials of the redoping product continues to undergo negative shift and the corrosion inhibition rate also increases on the basis of the corrosion potentials ofprimary doping product,which shows the redoped polyaniline products in different doping acid systems exhibit better performance than the primary product.The arc radius of the redoping product is also larger than that of the primary doping product.In the inorganic acid system,the corrosion inhibition effect of the redoping product of the molybdic acid system is the best,the corrosion inhibition rate is 74.67%,the impedance fitting value is984.85?/cm~2;in the organic acid system,the anticorrosion effect of tannic acid system is optimum,the erosion rate can reach 75.81%,and the impedance fitting value can reach 1017.31?/cm~2.This indicates that the redoping reconstructs the morphology of the polyaniline,accompanied by the superior performance of the polyaniline for the anion to enter.The redoping method can offer a new synthetic route to functional acid system limited by unsatisfactory primary product morphology,yield and so on.The functional acid enters the polyaniline molecule during the redoping process,which gives polyaniline new functionality or enhances its original performance. |
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