关键词: 导电水凝胶, 传感性能, 柔性可穿戴传感器, 抗菌性能

Abstract: In recent years, people are paying more and more attention to body health detection, and flexible smart wearable sensors have also been developed rapidly. Among them, hydrogel wearable sensors have attracted much attention because of their excellent performance. The hydrogel sensor can be closely applied to the surface of human skin. When the human body moves, it can quickly and accurately output the resistance change caused by the movement in the form of an electrical signal, which is beneficial to our real-time monitoring of human movement.
In this paper, poly(vinyl alcohol) (PVA) and hyaluronic acid (HA) were used as the substrates, and poly(3,4-ethylenedioxythiophene) conductive polymer and zinc oxide nanoparticles were used as the functional materials for the preparation of composite conductive hydrogels. Firstly, the composite conductive hydrogels were prepared by in situ polymerization and cyclic freeze-thawing method by adding 3,4-ethylenedioxythiophene (EDOT) monomer to ZnO/hyaluronic acid/poly(vinyl alcohol) (ZnO/PVA/HA) hydrogel solution after adding zinc oxide (ZnO) nano-polymer, which was prepared by mechanically assisted thermal method, to poly(vinyl alcohol)/hyaluronic acid (PVA/HA) hydrogel solution with different ratios. Zinc oxide/poly(3,4-ethylenedioxythiophene)/hyaluronic acid/poly(vinyl alcohol) composite conductive hydrogels (ZnO/PEDOT/PVA/HA) with strain sensing response and antimicrobial properties. The morphology and chemical composition of the ZnO nanoparticles and the conductive hydrogel were characterized using field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and X⁃ray powder diffractometer, respectively. The mechanical, sensing and antimicrobial properties of the hydrogels were also tested and analyzed, and the optimal parameter ratio of the composite hydrogels was determined as m(ZnO/EDOT/PVA/HA)=(0.03:0.1:(1:9)). The results showed that the addition of ZnO further improved the conductivity of the hydrogel, and the conductivity of the ZnO/PEDOT/PVA/HA (ZP) conductive hydrogel could reach up to 2.91 S/m, which was about 1.48 times higher compared with that of the PVA/HA/PEDOT (ZP0) conductive hydrogel without the addition of ZnO. the strain sensing effect of the hydrogel was tested on this basis Analyzed, the hydrogel has good tensile strain performance (≥100 %) and can give good velocity feedback at different tensile velocities, with sensitive response speed (<142 ms) and long-lasting stability (>1000 times). It is capable of monitoring and recognizing the motion signals of different parts of the human body. in addition, ZP0.3 conductive hydrogel has good antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).
The demand for flexible smart wearable sensors with sensing and antimicrobial properties is gradually increasing. The composite hydrogel sensor with sensing and antimicrobial properties prepared in this study can be used for human motion signal detection. The good sensing and antimicrobial properties confirm that the conductive hydrogel has good application prospects in flexible wearable strain sensors and medical health monitoring.

Key words: conductive hydrogel, sensing properties, flexible wearable sensors, antimicrobial activity