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Fabrication Of Conductive Composite Fiber Based On Coaxial Wet Spinning And Application Of Flexible Sensor

Posted on:2024-06-28Degree:MasterType:Thesis
Country:ChinaCandidate:H WuFull Text:PDF
GTID:2531307115994419Subject:Materials and Chemical Engineering (Materials Engineering) (Professional Degree)
Abstract/Summary:PDF Full Text Request
Stretchable conductive fibers with high stretch and conductive properties can meet the demand for human-computer interaction,health monitoring and intelligent control,etc.The wide application prospects make it an important research direction in the field of flexible electronic devices.Compared to traditional film-based electronics,fiber-based electronics can be woven into a variety of 3D shapes,better fit irregular surfaces,and can be easily integrated into textiles to easily monitor joint motion or precise position in one direction.Many conductive fibers have been developed for flexible sensors,but they often have narrow strain ranges or low sensitivity,which severely limit their applications in the field of flexible electronics.Therefore,it is of great practical value and guidance to develop flexible stretchable fiber sensors with excellent conductivity and mechanical properties,and capable of sensitive monitoring.Accordingly,in this thesis,two conductive fibers with core-shell and porous structures have been designed and prepared based on coaxial wet spinning.The mechanical properties,electrical conductivity and sensing performance of the fibers were investigated through a series of experiments,and the potential of the two conductive fibers in strain sensors was demonstrated.The main research contents are as follows:1)PHP@PHP-CNT conductive composite fibers:PHP@PHP-CNT conductive composite fibers with core-shell,porous structure were prepared by coaxial wet spinning with carbon nanotubes(CNT)as the conductive filler and polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)and polyurethane(PU)as the flexible substrate(PHP).The permeation threshold of PHP@PHP-CNT conductive composite fibers and the effect of conductive filler on the mechanical and sensing properties of the fibers were explored by varying the content of CNT,and the most suitable addition ratio was selected.The mechanism of fiber stretching sensitivity was investigated by strain-resistance and sensitivity analysis during fiber stretching.Cyclic loading-unloading tests were performed on PHP@PHP-CNT conductive composite fibers to evaluate the repeatability and durability of the fibers as strain sensors.The mechanical hysteresis effect was used to investigate the cause of the"shoulder peak"phenomenon.Finally,the application of PHP@PHP-CNT conductive composite fiber as a fiber-based strain sensor in the field of human joint motion detection was demonstrated.2)PHP@PAPAM conductive hydrogel fibers:A new monomer,acryloyl-L-phenylalanine(APhe),was first synthesized,and then a hydrogel poly(APhe-co-AAm)(PAPAM)was obtained by polymerizing two monomers,acrylamide(AAm)and acryloyl-L-phenylalanine(APhe),under UV light,and using this as the inner layer;continuous coaxial wet spinning with polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)and polyurethane(PU)(PHP)as the outer layer and hydrochloric acid as the coagulation bath to obtain PHP@PAPAM conductive hydrogel fibers with core-shell structures.The hydrogel fibers exhibited excellent mechanical properties with a tensile strength of 3.0 MPa and an elongation at break of 750%due to the abundant hydrophobic linkages and multiple hydrogen bonding synergies between the PAPAM polymer chains.A large amount of H+and Cl-in the solidifying bath hydrochloric acid entered inside the hydrogel network during the gel curing process,imparting excellent electrical conductivity(10.59 S m-1)to the hydrogel,while the hydrogel fibers demonstrated good frost resistance(-20°C)without introducing additional ions.Fiber sensors were used to monitor human activity,demonstrating their potential for wireless sensing applications,and to assemble fibers into fabrics used as stress sensors to detect the magnitude and spatial distribution of forces.PHP@PAPAM conductive hydrogel fibers showed promising applications in flexible wearable electronics due to their wide strain range(0-500%),fast response time(300 ms),and good cycling stability(>400 cycles).
Keywords/Search Tags:coaxial wet spinning, conductive fiber, carbon nanotube, ionic conductive hydrogel, flexible strain sensor
PDF Full Text Request
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