褶皱结构的壳聚糖-铁离子-聚丙烯酸导电水凝胶及其传感性能

Wrinkled structure conductive hydrogels of chitosan-Fe3+-Polyacrylic acid for sensors

  • 摘要: 壳聚糖基导电水凝胶兼具抗菌和导电等多功能,在电子皮肤、生物电子器件等领域具有广阔的应用前景。在实际应用中,要求导电水凝胶具有优异的力学性能和传感灵敏度。本工作将三氯化铁水溶液滴加到壳聚糖丙烯酸水溶液中,接着将丙烯酸原位聚合成聚丙烯酸,利用壳聚糖铁离子微凝胶和聚丙烯酸的溶胀行为的差异性,构建了褶皱结构的壳聚糖-铁离子-聚丙烯酸导电水凝胶(CS-Fe3+-PAA)。得益于壳聚糖铁离子微凝胶的能量耗散作用及其带来的褶皱结构,CS-Fe3+-PAA具有优异的力学性能和高灵敏度。在800%~1000%的大应变范围内,CS-Fe3+-PAA的灵敏因子(GF)值高达25.32,其韧性为2.54 MJ·m−3,断裂应变为1100%,断裂应力为0.6 MPa。CS-Fe3+-PAA应变传感器被成功用于检测人体多种活动,如手指、手肘和膝盖等关节弯曲活动,以及说话和吞咽等细微活动。独特的褶皱结构为高韧性和高灵敏度的壳聚糖基导电水凝胶提供设计思路和方法。

     

    Abstract: Chitosan-based conductive hydrogels have been applied in the fields of electronic skin and biomedical devices due to their antibacterial and conductivity properties. It is demanded that conductive hydrogels process excellent mechanical properties and sensing sensitivity in practical applications. In this work, ferric chloride aqueous solution was dripped into a solution of chitosan and acrylic acid, after which the acrylic acid was in situ polymerized to synthesis the chitosan-Fe3+-polyacrylic acid hydrogels (CS-Fe3+-PAA). The differential swelling behavior between chitosan ferric ion microgels and polyacrylic acid was used to construct a wrinkled structure of CS-Fe3+-PAA. The energy dissipation effect of chitosan ferric ion microgels and the resulting wrinkled structure enabled CS-Fe3+-PAA to exhibited excellent mechanical properties and high sensitivity. In the large strain range of 800%~1000%, the sensitivity factor (GF) of CS-Fe3+-PAA reached a value of 25.32. The toughness of hydrogels was 2.54 MJ·m−3, with elongation at break of 1100% and tensile strength of 0.6 MPa. The CS-Fe3+-PAA strain sensor has been successfully used to detect various human activities, including bending movements of joints such as fingers, elbows, and knees, as well as subtle actions such as speaking and swallowing. The unique wrinkled structure provides design ideas and methods for chitosan-based conductive hydrogels with high toughness and sensitivity.

     

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