| The silver/silver chloride electrode is one of the most commonly used reference electrodes and the most widely used biomedical electrode.It is currently widely used in various types of electrochemical sensors,biosensors and biomedical electrodes.However,with the rapid development of biomedicine in the field of health,medical electrodes and reference electrodes have higher requirements in terms of low cost,designability,and flexibility.At present,silver/silver chloride reference electrodes,although their It has excellent potential stability,but due to the need to frequently change the electrolyte during storage and use,and the inevitable existence of liquid potential affect the accuracy of the detection.In addition,the cost of commercial silver/silver chloride biomedical electrodes is still relatively high.These technical issues have prompted us to develop low-cost,flexible electrodes suitable for industrial mass production.There are various preparation methods for silver/silver chloride electrodes.Compared with other methods for preparing silver/silver chloride electrodes,silver/silver chloride electrode prepared by screen printing process of silver/silver chloride electrode paste has the advantages of flexible design,small and light,simple structure,low cost,good repeatability,high consistency,suitable for industrial production and so on.In this paper,through the adaptation of different silver/silver chloride materials,combined with the effect research of the conductivity,potential stability,hydration period,consistency,electrochemical impedance value and other properties of the paste electrode,the application verification of the ECG monitoring function is carried out.Through the comparative test of commercial ECG electrodes,it was verified that the prepared silver/silver chloride electrode has the potential to replace commercial ECG electrodes,and the results of this paper have high practical application value.The main research is as follows:?1?Using the characteristics of silver/silver chloride materials that can be slurried,the influence of the uniformity of the silver/silver chloride paste and the number of active centers on the performance of the slurry was analyzed.The self-made micron-level silver chloride powder,silver powder 1 and resin 1 were used as raw materials to prepare six groups of pastes with different silver/silver chloride ratios.The ratios are 3:1,2:1,65:35,3:2,1:1 and 1:2.The effects of different composition ratios on the conductive properties of the electrodes were studied.The 1:1 and 1:2 paste electrodes did not have conductivity.In addition,the electrode structure of the silver/silver chloride paste electrode is designed to facilitate the electrode connection electrode performance characterization device,which is composed of a substrate,a silver conductive layer,a silver/silver chloride layer,a wire,and an insulating layer.?2?The modification principle of PMMA resin is analyzed.Two or more monomers are copolymerized with MMA and a crosslinking agent is introduced to copolymerize and crosslink,which improves the heat resistance and uniformity of the modified PMMA resin.Using modified PMMA resin as a carrier,flake silver powder and spherical silver powder mixed powder were added to prepare a low-temperature curing type solderable functional silver paste.The results of the paste performance verification show that the low-temperature curing functional silver paste meets the requirements of the welding process at a curing temperature of 150?and a curing time of 15 min,and the volume resistivity is less than 1.0×10-4?·cm,adhesion>100 grid 4B,has good conductivity and adhesion.?3?Using an electrochemical workstation,characterize the electrode potential stability,hydration period,cyclic voltammetry,and consistency of six groups of silver/silver chloride working electrodes in different solution environments.The experimental results show that the silver/silver chloride paste electrode has a very short hydration period,excellent electrode potential stability and consistency,and the performance of these types of electrodes does not differ due to the difference in silver/silver chloride ratio.The hydration period of silver/silver chloride paste electrode will increase with the increase of chloride ion concentration in the environment.The cyclic voltammogram shows that all six groups of electrodes have reversible electrode characteristics.After the electrode potential of the silver/silver chloride paste is stable,the fluctuation value of the electrode potential within 1 hour<0.0001V,and the fluctuation value of the electrode potential within 12 hours<0.001V.The long-term stability of the potential is not affected by the concentration of chloride ions in the environment.It has the potential to be a biomedical electrode and a reference electrode.?4?Using an impedance analyzer and an ECG detection platform,the impedance value of the paste electrode and the detection ability of the ECG signal were characterized and compared with the commercial silver/silver chloride ECG electrode.The experimental results show that the impedance values of the six groups of electrodes are different in the range of 0-20000 Hz,and the electrode of silver:silver chloride=3:2 has the lowest impedance value in the entire frequency range.Electrocardiogram comparison shows that the 3:1,1:1 and 1:2 electrodes are extremely noisy and cannot be used for ECG signal detection.The ECG signal measured by the 3:2 electrode is basically the same as the ECG signal measured by the commercial silver/silver chloride electrode.It has the potential to replace the commercial ECG electrode for ECG monitoring,and it is the best choice for the biomedical electrode among the six groups of samples tested. |
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