Preparation Of Potassium Ion Electrochemical Fabric Sensor For Sweat By Electroassisted Core Spinning Technique

The traditional medical model is often centralized and passive,which is not conducive to early diagnosis and predictive analysis.In addition,blood sampling is invasive and easy to increase the psychological burden of patients.Wearable electrochemical sweat sensors have attracted widespread attention due to their non-invasive,sustainable ability to obtain dynamic physiological information for users and enable personalized healthcare.However,currently,most of the electrochemical sweat sensors use thin films,single fiber or yarn as sensing units,and there are great challenges in braid,large area detection,rapid response,long-term stability monitoring and other aspects.Herein,in this thesis,an electrochemical fabric sensor based on skin-core structured nanofiber sensing yarn was prepared by using a simple but novel electroassisted core spinning technology（EACST）to detect K⁺concentration in human sweat in situ.The specific research contents and conclusions are as follows.（1）The PPVN yarn with polyacrylonitrile（PAN）/polyvinylpyrrolidone（PVP）/K⁺carrier Valinomycin nanofiber as the skin and nylon yarn as the core layer was prepared by using EACST.The SEM images show that the PPVN yarn has an obvious skin-core structure,and its interfacial nanofibers are uniform and ordered,with an average diameter of 423.1 nm and good orientation.BET experimental data showed that PPVN yarn cortical nanofibers have a high specific surface area（8.85 m²/g）and a large number of connected mesoporous pores,the pore size mainly concentrated in 3.13～25.01 nm,with a wide pore size distribution（PSD）and a large pore volume（0.0271 cm³/g）.It can provide penetration and diffusion channels for absorbing sweat.（2）The electrochemical fabric sensor（PPVN-EFS）for detecting potassium ions in sweat was constructed by using PPVN yarn as sensing platform（weft yarn）and hydrophobic polyester（warp yarn）in one step.SEM images show that PPVN-EFS has a flat and distinct surface with The same appearance effects on both sides.The energy dispersive spectroscopy（EDS）shows that PPVN-EFS has the ability to trap K⁺in sweat.PPVN-EFS exhibits excellent air permeability（542.52 mm/s）,facilitates perspiration discharge,and meets the comfort needs of human senses.A physical model was designed and constructed to investigate the sweat wetting ability of PPVN-EFS.The results showed that sweat could be enriched in the PPVN yarn in the sensor region of PPVN-EFS,and was completely absorbed by the hydrophilic nanofibers in the interface layer of PPVN yarn,indicating that PPVN-EFS had excellent sweat absorption ability in the limited domain.Help the sensor to obtain stable and accurate sensing signals;Contact Angle（CA）measurements showed that PPVN-EFS had a rapid sweat-absorbing capability of 2.4 s.（3）Potassium ion sensing electrical signals of PPVN-EFS were quantitatively measured by potential method.The test results showed that PPVN-EFS had excellent selectivity,high sensitivity（34.7 m V/dec）and good linear relationship to potassium ions,and could generate potential response at 1×10^-5M K⁺concentration.With low detection limit（LOD）,the linear range is 1×10^-5～2×10^-1M;It shows low noise of 3.6×10^-2m V/s and good signal drift suppression characteristics,which can be stable output over 6000 s and has potential reproducibility.The current sensing response can occur quickly within 2.1 s.The results of cell survival/death staining and kit-8（CCK-8）experiment showed that PPVN yarn had no significant effect on cell viability,and the survival rate of cells was up to 97%,with exponential linear proliferation potential,which confirmed that PPVN yarn had good biocompatibility as the sensor platform of PPVN-EFS.By integrating PPVN-EFS into vest clothing,it can be used to track and evaluate human health by monitoring the change of peak current(104.02μA·cm^-2～162.07μA·cm^-2)as sweat K⁺physiological sensing signal.（4）The TPFV yarn with high mechanical strength and stability was successfully prepared by using EACST.SEM images showed that TPFV yarn had obvious core yarn structure and internal morphology.The surface of the interfacial nanofibers is smooth,uniform and orderly,with an average diameter of 474.2 nm and a coating thickness of 90.2μm,showing good orientation.There are a large number of nanopore structures with high orientation and uniform pore size distribution among nanofibers,which have high specific surface area and can provide penetration and diffusion channels for sweat absorption.Mechanical properties test showed that TPFV yarn has good flexibility and durability.The TPFV yarn is used as a sensor platform to integrate the electrochemical fabric sensor（TPFV-EFS）for detecting potassium ions in sweat,which has a good layered fabric structure.Sweat wetting experiment and contact Angle（CA）test showed that TPFV-EFS had significant localized perspiration absorption and wettability,avoiding random diffusion of sweat,and could be used for localized detection of sweat K⁺,which was conducive to the sensor to obtain stable and accurate sensing signals.Electrochemical sensing performance test showed that TPFV-EFS had high selectivity,long-term stability（over 9000 s）and linear correlation（R²=0.9914）,and showed low noise of 6×10^-3m V/s and good signal drift inhibition characteristics.