Study On Graphene Based PVDF-TrFE Electrospun Hybrid Pressure Sensors

Poly(vinylidene fluoride-co-trifluoro ethylene)(PVDF-TrFE)polymers have received significant interest of researchers and academicians in sensor application due to their exceptional sensing ability and piezoelectric response.The material is widely used in biomedical applications,as PVDF have higher flexibility,mechanical resilience and biocompatibility of the PVDF-TrFE polymer as compared to its inorganic counterparts,which makes it an ideal material for the piezoelectric pressure sensor.A high-performance electrically conductive and transparent PVDF-TrFE based electrode using the electrospinning technique was developed.The PVDF-TrFE based electrode was produced via spray coating of reduced graphene oxide(rGO),multiwall carbon Nanotubes(rGO-MWCNTs)as a nano-hybrid with various concentration followed by vapor phase polymerization(VPP)of poly(3,4-ethylenedioxythiophene)(PEDOT).The electrical performance of the fabricated composite nanofibers was measured by using a four-point contacts device.The results showed that the conductivity of the composited nanofiber mats was increased proportionately to 3916 S.cm-1 with the increase of weigh%of rGO/MWCNTs in the composite.The significant enhancement in electrical conductivity attributed to hybrid nanocomposite(rGO/MWCNTs/PEDOT)owing to the syergistic effect of hierarchical 1D and 2D hybrid carbon-based nanocomposite.Further,the fabrication of PVDF-TrFE doped with rGO(reduced graphene oxide)/MWCNTs(multi-walled carbon nanotubes)hybrid nanofibers mat via electrospinning is demonstrated.The electrospinning solution loaded with a different weight percent 1.8,2.4,3.2,and 4.0 of rGO/MWCNTs with improved.The peformance of the as developed nanofiber for the increased electrical,were analyzed.Furthermore,we demonstrated a self-powered,highly sensitive,and wearable e-skin based on a reduced-graphene-oxide(rGO)-multi-walled carbon nanotube(MWCNTs)doped poly vinylidene fluoride-trifluoro ethylene(PVDF-TrFE)hybrid Nano composite nanofibers mat by an electrospinning technique.Followed by an ultrathin coating layer of conductive polymer poly(3,4-ethylenedioxythiophene)using vapor phase polymerization on the rGO-MWCNT doped nanofibers to improve the piezoelectric pressure sensor response.The three dimentional(3D)rGO-MWCNTs-doped PVDF-TrFE@PEDOT(RMDPP)hybrid nano-composite nanofibers mat and the continuous self-assembled conductive layer in the nanofiber-based e-skin offer more contact-sites,which enabled piezoelectric pressure sensor can detect skin like multiple stresses induced by(the change in contact area under ultra-low load)minimal pressure.The results show that the PVDF-TrFE/rGO-MWCNTs hybrid nanofibers mat exhibited exceptional electrical,mechanical and sensing response as compared to neat PVDF-TrFE electrospun nanofibers.The consequences showes that,the RMDPP sensor exhibited a high-pressure sensitivity up to 19.09 kPa-1,with sensing range from 1 Pa to 25 kPa,and excellent cycling stability and repeatability over 14,000 cycles.The chemical structure and morphological characteristics of the prepared hybrid composite nanofiber mats were analyzed by using Field emission scanning electron microscopy(FESEM),Transmission electron microscopy(TEM),Fourier transforms infrared spectroscopy(FT-IR),Raman spectroscopy,X-ray diffraction(X-RD),and UV-visible spectroscopy.The wide-angle X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)was utilized to investigate the ?-phase transformation of the nanofibers.XRD and FTIR measurement suggest that the doping of the rGO-MWCNTs into the PVDF-TrFE matrix exhibits significant a to ? phase transformation for 3.2 wt.%rGO-MWCNTs in PVDF-TrFE nanofibers.The substantial improvement of the ?-phase is owing to the existence of highly electronegative fluorine which was further disclosed from XPS spectral analysis.DSC and TGA data indicate higher thermal stability due to enhanced crystallinity after the addition of Nano-additives.The developed self-powered piezoelectric pressures sensor showed excellent mechanical,flexible and wearable electronic skin with super-high sensitivity are highly desired and great value for biomedical application such as human health monitoring,voice recognition,masticatory movement and robotic skin.The pressure sensor showed outstanding sensing performances,when the device was enabled to monitor human body physiological activities,including heartbeat or wrist pulse,masticatory movement,voice recognition,and eye blinking signals,as well as the capability to the detection of static and dynamic pressure.This work suggests that the hybrid nanocomposite have promising prospects for potential applications as a low-cost transparent electrode for a piezoelectric pressure sensor.The newly developed PVDF-TrFE/rGO-MWCNTs nanofibers mat can be used as a potential material for the fabrication of piezoelectric pressure sensors.The investigational results indicate that the improved piezoelectric pressure sensor illustrates the perfect biomedical application in disease diagnosis and personal healthcare.