丝网印刷制备银/氯化银电极研究与应用进展

Progress in Research and Application of Silver/Silver Chloride Electrodes Prepared by Screen Printing

随着电化学传感器、生物传感器以及医用电极应用环境的发展,对银/氯化银参比电极和银/氯化银医用电极的可设计性、柔韧性、适应工业大批量生产等方面有了新要求。采用丝网印刷工艺制备再经低温固化成型的银/氯化银电极作为一种具备以上优点的低成本电极,已经成为了传感检测领域研究与应用的热点。从3个方面综述了丝网印刷制备银/氯化银电极的研究与应用进展:(1)丝网印刷制备银/氯化银电极的制备过程和优点、种类和区别以及电极的表征方法;(2)粘合剂选择、盐基层中氯化钾的浓度以及盐基层的层数等因素对丝网印刷制备银/氯化银电极氯离子敏感性、水合时间以及使用寿命等性能的影响;(3)丝网印刷制备银/氯化银电极在电化学生物传感器和医用电极方面的研究进展与应用。并对银/氯化银浆料影响电极灵敏性、稳定性的探究方向以及柔性衬底生物医用电极的接触阻抗提升途径进行了展望。

Silver/silver chloride electrodes are widely used in many fields such as health and medical treatment,food and environ-mental protection because of their good environmental compatibility and the advantage of a very low half-cell potential compared to bio-logical tissues.However,with the development of the application environment of electrochemical sensors,biosensors and medical elec-trodes,higher requirements are put forward for the corresponding reference electrodes and medical electrodes in terms of performance,designability,flexibility and industrial mass production.Therefore,in order to meet the needs of corresponding applications,it has be-come a trend to develop screen-printed electrodes to replace traditional electrodes.At present,the silver/silver chloride electrode pre-pared by the screen-printed process and then solidified at a low temperature,as a low-cost electrode that meets the above requirementshas become a hot spot in the field of sensor detection and application.This paper reviewed the progress in research and application ofscreen-printed silver/silver chloride electrode from three aspects:(1)The advantages of screen-printed silver/silver chloride elec-trodes,the types and differences of screen-printed silver/silver chloride electrodes,and characterization method of screen-printed sil-ver/silver chloride electrodes.Firstly,the shortcomings of different methods for preparing silver/silver chloride electrodes were intro-duced,but the screen-printed silver/silver chloride electrodes filled the shortcomings of these methods,with low production cost,fastresponse speed,good repeatability,and automatic production.Screen-printed silver/silver chloride electrodes could be divided intomedical electrodes and reference electrodes according to application:when used as medical electrode,contact impedance and signalto-noise ratio could also characterize electrode performance;When used as a reference electrode,it was characterized by potential sta-bility,potential drift rate,service life,hydration period and shelf life.The reference electrode was divided into reference electrodeand quasi-or pseudo-reference electrode according to whether it contained chloride ion functional layer.The function of chloride ionfunctional layer was to ensure the stability of chloride ion concentration of the electrode,so that the potential was not easy to fluctuatedue to environmental influence.(2)Choice of adhesive,concentration of potassium chloride in the salt layer,the number of layers ofthe salt layer and other factors affected the chloride ion sensitivity and service life of the screen-printed silver/silver chloride elec-trodes.By summarizing the influence of two different types of potassium chloride layers on the performance of the electrode,it was con-cluded that when the slurry composed of potassium chloride and siloxane-based polymer had an optimal value,the response of the elec-trode to the concentration was not obvious,and the service life would also increase.The potassium chloride layer was a hydrogel elec-trode,and the higher the concentration,the shorter the service life.Then,by summarizing the effects of different concentrations of po-tassium chloride salt base layer and printing two different layers of potassium chloride salt base layer on the performance of screenprinted silver/silver chloride electrode,it was concluded that the conductivity of the electrode would increase with the increase of po-tassium chloride percentage within a certain range,and when it exceeded a certain percentage,the dissolution of potassium chloridewould lead to the increase of chloride sensitivity of the electrode.However,two different potassium chloride base layers would signifi-cantly reduce the sensitivity of the electrode.(3)Research and application of screen-printed silver/silver chloride electrodes in thefields of electrochemical biosensors and biomedical electrodes.The reference electrode was an important part of the electrochemical bi-osensor system,so starting from the structure of the reference electrode,the internal electrolyte of the electrode was studied,and a sta-ble,reliable,sensitive,and accurate reference electrode was successfully prepared.The performance of the prepared reference elec-trode was verified by cyclic voltammetry and amperometric analysis.The test results showed that the prepared electrode had excellentperformance and could provide reliable signals for accurate measurement of biosensors.The performance and human body fitted of thescreen-printed silver/silver chloride flexible substrate electrode met the requirements of medical electrodes after testing.Finally,the re-search direction of the silver/silver chloride slurry ratio affecting the sensitivity and stability of the electrodes and the contact imped-ance improvement path of the flexible substrate biomedical electrodes were prospected.