Research On Preparation Of Flexible Electrode And Electrochemical Modification Of Conductive Polymer

Bioelectrical signals are one of the most basic physiological signals of living organisms.Monitoring bioelectrical signals can diagnose and prevent many physiological diseases.The collection of bioelectrical signals requires the use of measuring equipment,and the electrode,as the hardcore part of the measuring equipment,can play the role of collecting and transmitting bioelectrical signals.Conventional electrodes are generally rigid electrodes based on metal and semiconductor materials,which do not match the mechanical modulus of biological tissues,and cannot achieve long-term stable recording and stimulation.The flexible electrode has low Young's modulus and can fit with the curved surface structure closely,which can be well applied to various biological environments and greatly meet the daily monitoring needs,especially in the field of wearable devices.In this paper,we prepared two kinds of flexible gold electrodes based on photolithography technology,and carried on relevant performance tests and animal implantation experiments to confirm the safety and stability of flexible gold electrodes.But to even further reduce the impedance and improve the charge storage capacity,conductive polypyrrole films and conductive polyaniline films with high conductivity,large specific surface area and good charge storage capacity were modified on the surface of ITO conductive glass,which provided guidance for the subsequent modification of flexible gold electrode.In the first chapter,the research progress of flexible electrode materials,processing technology and conductive polymer interface modification technology was reviewed,and the application of flexible electrode in bioelectricity detection was introduced.In the second chapter,the eight-site flexible gold electrode array based on polyimide film prepared by photolithography,magnetron sputtering and other processes.The surface topography,film resistance,electrochemical performance and biocompatibility of the flexible gold electrode were tested.It was verified that the flexible gold electrode had stable electrical conductivity,good electron transfer ability and excellent biocompatibility.However,due to the low surface roughness,the charge storage ability of the electrode was poor.In the third chapter,a series of polypyrrole films with p-toluene sulfonic acid as dopant were deposited on ITO conductive glass surface by constant current method.The influence of the deposited charge density during the polymerization process on the electrochemical performance and surface topography of the polypyrrole film was discussed.According to the results,compared with the flexible gold electrode,the charge capacity density after modification by polypyrrole was increased by more than130 times.In the fourth chapter,a series of polyaniline films were electrochemically polymerized on ITO conductive glass by cyclic voltammetry using sulfuric acid and p-toluenesulfonic acid as dopant.The influences of different dopants on the charge capacity,impedance surface and surface topography of polyaniline films were studied.The enhancement of the electrochemical properties of polyaniline films by multiwalled carbon nanotubes(MWCNTs)was confirmed.