Investigation On The Polarization And Performance Of Flexible Carbon Black/polymer Composite Bio-electrodes

Bioelectrical monitoring can effectively help to judge the health status of heart,brain,muscle and other tissues and organs,which is an important research direction in the field of wearable technology.Bio-electrodes play an important role in wearable bioelectric monitoring.At present,silver/silver chloride gel electrode is widely used because of its low and stable polarization potential and low impedance.However,the silver/silver chloride gel electrode is disposable electrode,and the performance of the electrode will be greatly reduced with the dehydration of gel.In order to replace silver/silver chloride gel electrode,researchers have explored a variety of dry electrode materials.However,the reported bio-electrodes still face many problems and challenges:1.The preparation process is complex.In order to realize the flexibility of dry electrode materials,it is necessary to construct low dimensional and curved electrode structures through complex processing methods to meet the requirements of low impedance and low resistivity of bioelectrode.2.The polarization potential is unstable.Although the reported bio-electrodes can measure good signal in a short time,it is easy to have signal decay in a long-term monitoring because of its unstable polarization potential.In view of the above problems and challenges,we study the polarization behavior of carbon black/polymer composite bio-electrodes and its influence on performance stability.1.The polarization behavior and stability of gold,platinum,carbon,silver and silver/silver chloride gel electrodes were studied.The effects of polarization potential,resistivity and interface impedance on bioelectrical signal measurement were studied.2.Using poly(vinylidene fluoride)(PVDF)as polymer substrate and carbon black(CB)as conductive filler,flexible CB/PVDF composite film electrode was prepared through a physical mixing method.Its resistivity is as low as 0.3 ?·cm and has stable polarization potential.The bioelectricity acquisition ability of CB/PVDF flexible composite electrode was studied.The measured ECG signal intensity was about 0.3 m V,which is comparable to that of commercial silver/silver chloride dry electrode material.3.Using styrene-ethylene-butylene-styrene(SEBS)as polymer substrate and carbon black as conductive filler,CB/SEBS elastic film electrode was prepared according to the method reported in the previous chapter.The comprehensive performance of the electrode was optimized by adjusting the content of CB.The electrode has low and stable polarization potential,and a resistivity as low as 1.53 ?·cm,good tensile cycling,and can be attached to the skin surface.The bioelectrical signal intensity measured by the electrode is better than that of the commercial silver/silver chloride gel electrode,and its stability reaches the level of commercial wet electrode.Based on elastic CB/SEBS composite electrode,a bioelectrical monitoring bracelet was prepared and used to collect finger EMG signal.4.CB/SEBS elastic fiber electrode was prepared by wet spinning.The comprehensive performance of the electrode was optimized by adjusting the concentration of spinning solution and CB content.The change of electrode resistance was maintained at 6% after 1000 stretching cycles,and the measured ECG signal intensity was maintained at 0.9 m V,which is better than that of commercial silver/silver chloride gel electrode,and its stability reaches the level of commercial wet electrode.A wearable bioelectrical monitoring system is finally constructed by integrating it with the fabric,ECG acquisition module,Arduino board,Bluetooth module,mobile power supply,etc.