The poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) polymer based on electrostrictive polymers is essential in smart materials applications such as actuators, transducers, microelectromechanical systems, storage memory devices, energy harvesting, and biomedical sensors. The key factors for increasing the capability of electrostrictive materials are stronger dielectric properties and an increased electroactive β-phase and crystallinity of the material. In this work, the dielectric properties and microstructural β-phase in the P(VDF-HFP) polymer were improved by electrospinning conditions and thermal compression. The P(VDF-HFP) fibers from the single-step electrospinning process had a self-induced orientation and electrical poling which increased both the electroactive β-crystal phase and the spontaneous dipolar orientation simultaneously. Moreover, the P(VDF-HFP) fibers from the combined electrospinning and thermal compression achieved significantly enhanced dielectric properties and microstructural β-phase. Thermal compression clearly induced interfacial polarization by the accumulation of interfacial surface charges among two β-phase regions in the P(VDF-HFP) fibers. The grain boundaries of nanofibers frequently have high interfacial polarization, as they can trap charges migrating in an applied field. This work showed that the combination of electrospinning and thermal compression for electrostrictive P(VDF-HFP) polymers can potentially offer improved electrostriction behavior based on the dielectric permittivity and interfacial surface charge distributions for application in actuator devices, textile sensors, and nanogenerators.

In this work, we improved the electromechanical properties, electrostrictive behavior and energy-harvesting performance of poly(vinylidenefluoridene-hexafluoropropylene) P(VDF-HFP)/zinc oxide (ZnO) composite nanofibers. The main factor in increasing their electromechanical performance and harvesting power based on electrostrictive behavior is an improved coefficient with a modified crystallinity phase and tuning the polarizability of material. These blends were fabricated by using a simple electrospinning method with varied ZnO contents (0, 5, 10, 15 and 20 wt%). The effects of the ZnO nanoparticle size and content on the phase transformation, dielectric permittivity, strain response and vibration energy harvesting were investigated. The characteristics of these structures were evaluated utilizing SEM, EDX, XRD, FT-IR and DMA. The electrical properties of the fabrication samples were examined by LCR meter as a function of the concentration of the ZnO and frequency. The strain response from the electric field was observed by the photonic displacement apparatus and lock-in amplifier along the thickness direction at a low frequency of 1 Hz. Moreover, the energy conversion behavior was determined by an energy-harvesting setup measuring the current induced in the composite nanofibers. The results showed that the ZnO nanoparticles’ component effectively achieves a strain response and the energy-harvesting capabilities of these P(VDF-HFP)/ZnO composites nanofibers. The electrostriction coefficient tended to increase with a higher ZnO content and an increasing dielectric constant. The generated current increased with the ZnO content when the external electric field was applied at a vibration of 20 Hz. Consequently, the ZnO nanoparticles dispersed into electrostrictive P(VDF-HFP) nanofibers, which offer a large power density and excellent efficiency of energy harvesting.

In this work, a superhydrophobic surface of poly (vinylidenefluoridene-hexafluoropropylene) (P(VDF-HFP)) fibers was fabricated by means of electrospinning technique. The effects of flow rate on the morphology and hydrophobicity of P(VDF-HFP) nanofibers were investigated by scanning electron microscopy (SEM) and water contact angle (WCA), respectively. The results exhibit a uniform P(VDF-HFP) fiber mat at the lowest flow rate. However, the presence of bead-on-string the fibers was exhibited at higher flow rate. The average fiber diameter of P(VDF-HFP) fibers is increased with increasing flow rates. The WCA values of the P(VDF-HFP) fibers with bead-on-string structure could reach up to 158.60°, indicating as the superhydrophobicity. These as-received porous P(VDF-HFP) fibers with superhydrophobic surface are attractive properties for self-cleaning materials used for further several industrial applications.

This study proposes a piezoelectric polyvinylidene fluoride (PVDF) patch for detecting the movement of the biceps brachii muscle. The polyurethane (PU) elastomer was chosen to perform as an artificial muscle. The PVDF patch rigidly glued onto the stretching PU strip could generate the charge linearly with its applied force. The large strain of 1-4 % of the PU at a low driving voltage has led to the determination of the piezoelectric charge coefficient (d 31 ) of 30 pC/N for the PVDF. The sensing PVDF-PU patch in this study is promising for detecting the electromyography of the biceps brachii muscle movements which can be repeatable used with ease.