Preparation And Properties Of Antibacterial And Conductive Silk Fabric Based On Polypyrrole

Traditional wearable electronic devices are in demand for their portability and timeliness,but they are usually uncomfortable to wear.Within this content,combining flexible substrates with electronic devices can be a valuable method to prepare flexible electronic devices.Fabric,as the most flexible materials in daily life,exhibits good mechanical properties and wearability performance,can meet the requirements of the flexible substrate.However,the insulating property of fabric limit its application in the field of flexible electronics.Preparation of electronic devices based on fabric has become a research hotspot.In view of the above background,silk fabric（SF）with soft texture,moisture absorption and excellent mechanical properties was used as the substrate,and Polypyrrole（PPy）was introduced to endow SF conductivity,and SF-based flexible electronic devices are prepared.Antibacterial agents were introduced to inhibit the bacterial growth tendency of SF,thus the stability of flexible electronic devices was improved during long-term use.The performance of sensing,energy storage and power supply of the prepared flexible electronic devices were investigated.The main research contents are as follows:（1）SF was modified by Polydopamine（PDA）which can be chloridized to obtain PDA-Cl/SF.PPy/PDA-Cl/SF was obtained by chemical polymerization using ferric chloride（Fe Cl₃）as oxidant.The chemical structure,microstructure and elemental composition of PPy/PDA-Cl/SF were characterized by FT-IR,SEM and EDS,and the results showed that the N-Cl bond and PPy was existed on the surface of PPy/PDA-Cl/SF.The electrical properties of PPy/PDA-Cl/SF were tested using an electrochemical workstation and a four-probe tester.The electrical conductivity of the PPy/PDA-Cl/SF was 0.485 S/cm,the specific capacitance was 896.7m F/cm²,and the capacitance retention rate was 53.7%after 1000 charge-discharge cycles.The PPy/PDA-Cl/SF was assembled onto the finger and the finger movement was monitored by real-time resistance changes.The results showed that PPy/PDA-Cl/SF had good sensitivity.The antibacterial tests showed that within 10 min contaction,95.6%of E.coli and 99.7%of S.aureus were killed by PDA-Cl/SF and 98.7%of E.coli and 98.6%of S.aureus were killed by PPy/PDA-Cl/SF,respectively.（2）In order to simplify the preparation process,silver（Ag）without the requirement of chlorination was used as an antibacterial agent.Firstly,the surface of SF was modified by PDA,then silver nitrate（Ag NO₃）was used as oxidant to prepare Ag-PPy/PDA/SF.The chemical structure,microstructure and elemental composition of Ag-PPy/PDA/SF were tested by FT-IR,XRD,SEM and EDS,and the results showed that the Ag and PPy was existed on the surface of Ag-PPy/PDA/SF.The electrical properties of Ag-PPy/PDA/SF were tested using electrochemical workstation and four-probe tester.The electrical conductivity of Ag-PPy/PDA/SF was 2.99 S/cm,the specific capacitance was 604 m F/cm²,and the capacitance retention rate was only 26.51%after 1000 charge-discharge cycles.Electromagnetic shielding test showed that Ag-PPy/PDA/SF had good electromagnetic shielding performance and the shielding efficiency was more than 20 d B in the range of 8.2～12.4 GHz.The antibacterial tests showed that Ag-PPy/PDA/SF had good antibacterial effect on both E.coli and S.aureus,and the diameter of the antibacterial zone was greater than 1 mm.（3）Carbon nanotube（CNT）was introduced in order to improve the stability of the composite fabric during the long time charging and discharging of constant current process.The surface of SF was modified by PDA.Based on the weak reductibility of PDA,Ag/PDA/SF was obtained by immersed in Ag NO₃ solution.CNT/Ag/PDA/SF was obtained by uploading CNT through the dipping-drying process.PPy/CNT/Ag/PDA/SF was prepared by chemical polymerization using Fe Cl₃ as oxidant.The influence of dipping times on CNT loading and electrical conductivity was investigated.After 11 times dipping,the CNT loading was 0.0638 g and the square resistance of CNT/Ag/PDA/SF was 2.75 KΩ/sq.The chemical structure,microstructure and elemental composition of PPy/CNT/Ag/PDA/SF were investigated by FT-IR,XRD,Raman,SEM and EDS,and the results showed that the Ag,CNT and PPy was existed on the surface of PPy/CNT/Ag/PDA/SF.The electrical properties of PPy/CNT/Ag/PDA/SF were tested by electrochemical workstation and four-probe tester.The specific capacitance of PPy/CNT/Ag/PDA/SF was 7.01 F/cm²,and the capacitance retention was 71.56%after 1000charge-discharge cycles,which was 18.96%higher than the capacitance retention of PPy/Ag/PDA/SF.PPy/CNT/Ag/PDA/SF had higher sensitivity to human movement,and the resistance change was more obvious when monitoring finger movement;the electromagnetic shielding test showed that PPy/CNT/Ag/PDA/SF had good electromagnetic shielding performance,and the shielding efficiency was more than 22 d B in the range of 8.2～12.4 GHz.The antibacterial tests showed that PPy/CNT/Ag/PDA/SF had good antibacterial effect on both E.coli and S.aureus,which showed an obvious antibacterial zone.（4）In order to extend the application,the above three conductive fabrics were used as electrodes to prepare friction nanogenerators（TENG）.The effects of electrode conductivity,friction material and external force on the open-circuit voltage of single-motor mode TENG and contact-separation TENG were investigated.The contact-separation type TENG which obtained by PPy/CNT/Ag/PDA/SF prepared with a pyrrole concentration of 0.15 mol/L as the electrode and polytetrafluoron（PTFE）as the friction material had the best performance.The results showed that the contact-separation type TENG can well identify the state of human motion（standing,walking,running）and movement posture（forefoot-first,midfoot-first,heel-first）,and had good responsiveness to the degree and frequency of external force.