Improved Piezoelectric Sensing Performance of P(VDF–TrFE) Nanofibers by Utilizing BTO Nanoparticles and Penetrated Electrodes

Abstract

Piezoelectric polymers with good flexibility have attracted tremendous attention in wearable sensors and energy harvesters. As the piezoelectricity of polymers such as polyvinylidene fluoride (PVDF) and polyvinylidene fluoride− trifluoroethylene [P(VDF−TrFE)] is lower than that of their ceramic counterparts, various approaches have been employed to improve the piezoelectric output of PVDF-based sensors, such as electrospinning, heat annealing, nanoconfinement, polymer blending, and nanoparticle addition. Here, we report two strategies to improve the piezoelectric sensing performance of polymer-based piezoelectric nanofibers, which include the formation of barium titanate (BTO)/P(VDF−TrFE) composite nanofibers and fabrication of penetrated electrodes to enlarge the interfacial area. BTO/P(VDF−TrFE) nanofibers with a BTO weight fraction of 5 wt % exhibit the maximum β-phase crystallinity and piezoelectricity. The piezoelectric output of the BTO/ P(VDF−TrFE) nanofiber mat is significantly improved compared with that of pristine P(VDF−TrFE), which is confirmed by piezoresponse force microscopy (PFM) and compression loading tests. In order to form the penetrated electrodes, oxygen (O 2 ) plasma treatment is employed, followed by an electroless plating process. The BTO/P(VDF−TrFE) nanofibers with penetrated electrodes demonstrate increased dielectric constants and enhanced piezoelectric outputs. A BTO/P(VDF−TrFE) nanofiberbased sensor with penetrated electrodes is capable of discerning the energy of a free-falling ball as low as 0.6 μJ and sensing the movement of a walking ant.

Composites, Fabrication and Application of Polyvinylidene Fluoride for Flexible Electromechanical Devices: A Review

“…Adding nanoclay [96] to PVDF can prompt the formation of the β-phase in the spinning process, which is an ideal method to prepare piezoelectric nanofibers. BTO nanoparticles were used to improve the P(VDF-TrFE) nanofibers' piezoelectric sensing properties ( Figure 4a) [97]. BTO/P(VDF-TrFE) nanofibers doped with BTO nanoparticles have the largest β-phase crystallinity and the best piezoelectric properties.…”

“…Xiaohe et al [97] fabricated (BTO)/P(VDF-TrFE) composite nanofibers by electrospinning and were able to distinguish and sense the movement of walking ants and the energy of a free-falling ball as low as 0.6 µJ (Figure 8c). Sang et al [9] fabricated flexible lead-free piezoelectric nanofibers composed of PVDF and BNT-ST ceramic by electrospinning.…”

Bio-inspired Flexible Lateral Line Sensor Based on P(VDF-TrFE)/BTO Nanofiber Mat for Hydrodynamic Perception

“…After treatment with O 2 plasma for 3 min, an Au/Cr (160 nm/40 nm) layer was sputtered on the PI film by magnetron sputtering with a stencil mask to form the bottom electrodes of the sensor (Figure 3b). The P(VDF-TrFE)/BTO nanofiber mat was fabricated by a far-field electrospinning method and the detailed electrospinning process was demonstrated in our previous work [33]. The thickness of the nanofiber mat was 40 µm, which was well controlled by adjusting the electrospinning time.…”

“…of the sensor (Figure 3b). The P(VDF-TrFE)/BTO nanofiber mat was fabricated by a far-field electrospinning method and the detailed electrospinning process was demonstrated in our previous work [33]. The thickness of the nanofiber mat was 40 μm, which was well controlled by adjusting the electrospinning time.…”

“…PVDF and its copolymer poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] are excellent sensor materials as they provide advantages such as energy conservation, excellent processability, and conformal elasticity [29,30]. The piezoelectricity of the PVDF-based polymers can be improved by incorporating inorganic materials such as ZnO, PZT, barium titanate (BTO), graphene and gold nanoparticles (AuNPs) [31][32][33][34][35]. Moreover, electrospinning is an effective way to obtain highly aligned piezoelectric nanofibers with anisotropic piezoelectricity [36].…”