Study On The Preparation Of Composite Fibrous Helix And UV Shielding Performance

Relative to 2D rigid electronic device,fibrous flexible electronics possesses stretchability,lightweight,adjustable mechanical and electrical properties,which have the transform a wide range of applications,including wearable sensors,stretchable conductors and electrodes,and deformable energy-harvesting and storage devices.However,most flexible electronics show unsatisfactory due to their limited deformation capacity.Compared to traditional fiberous yarns,because of the multistage helical structure,the local strain of the fibrous is not matched with the external strain,which lead to local strain suppression and global strain lifting.Therefore,compared with traditional fibrous yarns,fibrous helix structure has stronger stretchability.Herein,we engineered composited nanofibrous helix through electrospinning combined with mechanical twisting technology,and their performance,application and mechanism are systematically studied.1.We prepared Ti O₂//PU@Ag NWs composite nanofibrous helix assemblies using electrospinning and twisting method.The UV shielding properties of different structures and tensile strains were investigated.The results show that composite nanofibrous helix exhibiting strain-insensitive UV protection at 0%～500%strain for UV shielding as well as strain-sensitive UV monitoring at 500%～1500%strain for UV early warning.Compared with previously reported common nanofibrous membrane devices,the as-prepared composite nanofibrous helix shows great advantages in terms of stability and UV protection,especially at large strains.Furthermore,the helix demonstrates multiple functions of wear resistance,antibacterial properties,biodegradation and knittability.This versatile strategy holds great promise for wearable electronics and multifunctional devices.2.We prepared Ti O₂//PU//LM composite nanofibrous helix assemblies using electrospinning and twisting method.The mechanical and electrical properties of liquid metal with different content and fibrous structure were characterized.The results show that composite nanofibrous helix possessed high stretchability（3000%）and good conductivity（128975 S/m）.Most importantly,it showed 35009 S/m conductivity under3000%.Due to the added Ti O₂ NPs,the composite nanofibrous helix presented excellent UV shielding performance.Besides,the composite nanofiberous helix also have good biocompatibility.This macroscopic structure design provides a new option for the development of flexible electronics.3.First,the silk was modified by feeding method.Then,the PU,PVA,PAN and CA nanofibrous membrane were prepared by electrospinning.Finally,their structures and properties are characterized.The results showed that the PU-based Tg regulates the heating temperature of PU,which generated bond points for the nanofibrous membrane,and then improved the interfacial binding force between silk and PU.Comparing the infrared spectra of ordinary silk and modified silk,the modified silk structure had no change.The UV shielding performance of the silk fed with cinnamic acid and Ti O₂ NPs was better than ordinary silk.