Research On Preparation And Performance Of Sensing Functional Flexible Fiber

In recent years,flexible wearable smart textiles have increasingly become a research hotspot for scholars at home and abroad.Compared with traditional rigid electronic devices,it has the characteristics of flexibility,elasticity,stability and safety.Finally,it can provide advanced applications in multiple fields and forms such as intelligent robots,personal health monitoring,and human-computer interaction.The flexible fiber with sensing function,which is the basis of its weaving,has also attracted much attention.It refers to the flexible fiber that responds to stresses such as temperature,humidity,photothermal,or sweat.Therefore,in this thsis,we have prepared two flexible fibers with sensing functions.The structure and performance of the above fibers was studied,and the main research contents are as follows:1.Moisture-sensitive flexible fiber: It is made of polydimethylsiloxane(PDMS)flexible fiber as the substrate and coated with MIL-88A@PVDF moisture-sensitive layer on the surface.Then,the moisture sensitivity characteristics of the fiber were studied,including shape changes under the influence of environmental humidity alone and in various organic solvents.It also uses scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),tensile stress-strain and thermogravimetric analysis(TG)and other testing methods for further analysis.The results show that the surface of MIL-88A@PVDF/PDMS fiber has been successfully loaded with MIL-88 A crystals,which are cubic with a certain thickness.In the absorption/desorption process,the shape change of the fiber is only affected by the structural change of MIL-88 A.After a large number of experimental verifications,it can be concluded that the fiber shape gradually stretches as the humidity increases and gradually shrinks as the humidity decreases.In addition,the shape changes in different organic solvents can be divided into three types: stretching in water,ethanol,and acetonitrile solution;stretching first and then recovering in acetone solution;irregular crimping in toluene and chloroform solution.At the same time,the fiber has a certain degree of flexibility,stretchability and thermal stability.2.Special long-afterglow luminescence flexible fiber: It is prepared by polyurethane/polyvinylidene fluoride(PU/PVDF,mass ratio 1:1)compositing with ZFP particles via wet spinning process,which emit long afterglow luminescence after being taken out of liquid nitrogen.Among them,ZFP particles are particles with a shell-core structure formed by wrapping polyvinylidene fluoride-hexafluoropropylene copolymer(PVDF-HFP)particles on the outer layer of Zn S:Cu fluorescent particles.In addition to verifying the luminescence characteristics through a large number of experiments,it also uses scanning electron microscopy(SEM),X-ray diffraction(XRD),fluorescence spectroscopy(PL),and tensile stress-strain and other testing methods for further analysis.The results show that the Zn S:Cu phosphor itself has the special long-afterglow luminescence performance,and the doping of PVDF-HFP can enhance the luminous intensity as well as prolong the luminous time,which lasts more than 100 s.The PU/PVDF substrate can balance the luminous performance and mechanical properties.It should be noted that the ZFP+PU/PVDF(G)fiber with a diameter of 0.75 mm has the best mechanical properties.The breaking elongation of it is greater than 400%,while the breaking stress is close to 2MPa.Meanwhile,it has good repeated stretch recovery.There are various braided ropes and fabrics obtained by weaving the fiber.The tighter the woven structure,the lower the heat dissipation rate and the better the heat preservation effect.In turn,the effective long afterglow emission time is extended.In a word,the two kinds of flexible fibers with sensing function prepared in this paper have broad application prospects,and provide new ideas for the field of flexible wearable smart textiles.