Preparation And Properties Of Regenerated Silk Fibroin-Based Composite Functional Materials

Biomaterial from nature plays an essential role since ancient era in making mankind comfort.Owing to the extraordinary features,such as the good mechanical strength,moderate elongation,biocompatible and nonhazardous properties,natural silk has been widely applied in diversified fields including textile,biomedical and biotechnological industries.However,the mechanical strength and conductive properties from naturally obtained silk fiber is still limited,which consequently to a large extent restricts their applications towards futuristic uses.In this regard,the exploration of new synthesis protocol for manipulating properties of artificial silk fibers is one of the key concerns of current research.In this work,the preparation and properties of regenerated silk fibroin(RSF)-based composite conductive films and composite fibers were studied.By doping other functional materials(SiO2,CNT),the composite properties of regenerated silk fibroin were controlled from mesoscopic structure.An extension of its performance and range of applications.1.The flexible RSF-CNT composite conductive film was prepared by solution blending and casting.The conductivity of the flexible conductive film reached 746 S/m.In addition,the RSF-CNT composite conductive film has photothermal response.After 30 s irradiation with 808 nM laser,the maximum temperature rise reaches 32℃.At 30 °C and 60 ℃,the resistance of the composite film can change cyclically.Achieve certain temperature sensing performance.2.High-strength RSF-SiO2 composite fiber was prepared by wet spinning method.The breaking strength of composite fiber reached 458±21 MPa and the breaking strain reached 54＋7%,compared with pure regenerated silk fibroin fiber(243±3 MPa),51＋4%),the breaking strength is 88.5%higher,and the breaking strength is 33.5%higher than that of natural degummed silk fiber(343±22 MPa,12±4%).The main reason is that the addition of SiO2 microspheres provides a heterogeneous nucleation template for the crystallization of silk fibroin,which induces the crystallization process of silk fibroin,which increases the β-sheet content in the secondary structure of regenerated silk fibroin fiber by 6.3%.The crystallinity is increased by 13.6%,which strengthens the mechanical properties of the fiber.3.Highly conductive RSF-CNT composite fiber was prepared by wet spinning method,and the high conductivity of silk-based composite fiber was realized for the first time.The electrical conductivity of RSF-CNT composite fiber is as high as 638.9±60.9 S/m,and the breaking strength reaches 169.3±10.4 MPa.When the dry weight ratio of CNT is 20%～30%,the CNT clusters inside the fiber overlap partially,and the overlap probability and electrical conductivity increase with the CNT content.When the dry weight ratio of CNT reaches 35%,the internal orientation is significantly improved,the probability of overlapping between CNT clusters is significantly improved,a good conduction state is formed,and the electrical conductivity is significantly improved.Further,the RSF-CNT composite conductive fiber is prepared into a humidity sensing unit of the smart wearable mask,and the real-time monitoring of the breathing curve on the mobile device is realized,which provides a new solution for the future intelligent large health monitoring.