Study On The Electrochemical Performance Of Polyindole/Polypyrrole-based Composite

Conductive polymer is a kind of organic macromolecule with?-conjugated backbone that can conduct electricity.The conductivity can be tuned through chemical or electrochemical doping,leading to the change between insulator and conductor.Conductive polymers have very unique properties,including not only the electrical and optical properties of metals and inorganic semiconductors,but also the flexibility and processability of organic polymers,as well as electrochemical redox activities.These characteristics make conductive polymers play an important role in the development of optoelectronic devices,energy storage/conversion,and sensors.In this paper,we mainly explore the application of conductive polyindole/polypyrrole in energy storage,detection and sensors.(1)A brief overview of the conductive polymer is described,including an introduction to its conductive mechanism,doping process,preparation method and application.In addition,a brief overview of the classification,preparation methods and applications of conductive hydrogels is also given.(2)A new type of monomer for conductive polyindole/thiophene(P(In/Th)),was prepared through a simple Passerini reaction,and the conductive polymer was formed by in-situ oxidation polymerization,and its electrochemical performance and ion detection capability were studied.After doping with phytic acid,P(In/Th)showed a specific capacitance of 1170 F g^-1,a power density of 2614.4 W kg^-1 and an energy density of 56.5Wh kg^-1.P(In/Th)has obvious aggregation-induced luminescence characteristics,i.e,emitting blue fluorescence.Fe³⁺ions and has good selectivity for fluorescence quenching,the lowest detection limit of the conductive P(In/Th)for Fe³⁺was 3×10^-5 M by fluorescence analysis and chronoamperometry.At the same time,due to the oxidation-reduction reaction of Fe³⁺,the capacitance performance of the complex system of P(In/Th)-phytic acid and Fe³⁺is further improved to 1300 F g^-1.Its excellent energy storage and Fe³⁺detection performance provide more possibilities for functional polyindole/thiophene in energy storage and sensor applications.(3)Using polyacrylamide(PAM)/natural pectin(Pct)double cross-linked interpenetrating network as the hydrogel matrix,the traditional conductive polypyrrole(PPy)was formed in situ in the hydrogel system to prepare a high tensile strength,non-toxic PAM/Pct/PPy conductive hydrogel.As a natural polymer in the system,pectin not only increases the cross-linking sites of the conductive hydrogel,but also improves the biocompatibility of the conductive hydrogel.The elongation at break of PAM/Pct/PPy hydrogel can reach 842%,and the tensile strength is 80 KPa.Under the condition of 85%compression,the hydrogel was not destroyed and showed strong compression resistance.By calculation,the average conductivity of the hydrogel is 5.7 S m^-1,which is equivalent to the conductivity of the pure PPy hydrogel reported in the literature.In addition,the hydrogel exhibits high strain and pressure sensitivity,and can sense pressure changes of 0.1 N.As a wearable sensor,the change of its relative resistance shows good stability and repeatability,which is expected to be applied to the detection of human activities.