Poly Vinylidene Fluoride-trifluoroethylene Research Articles

On-demand fabrication of piezoelectric sensors for in-space structural health monitoring

Inflatable structures, promising for future deep space exploration missions, are vulnerable to damage from micrometeoroid and orbital debris impacts. Polyvinylidene fluoride-trifluoroethylene (PVDF-trFE) is a flexible, biocompatible, and chemical-resistant material capable of detecting impact forces due to its piezoelectric properties. This study used a state-of-the-art material extrusion system that has been validated for in-space manufacturing, to facilitate fast-prototyping of consistent and uniform PVDF-trFE films. By systematically investigating ink synthesis, printer settings, and post-processing conditions, this research established a comprehensive understanding of the process-structure-property relationship of printed PVDF-trFE. Consequently, this study consistently achieved the printing of PVDF-trFE films with a thickness of around 40 µm, accompanied by an impressive piezoelectric coefficient of up to 25 pC N−1. Additionally, an all-printed dynamic force sensor, featuring a sensitivity of 1.18 V N−1, was produced by mix printing commercial electrically-conductive silver inks with the customized PVDF-trFE inks. This pioneering on-demand fabrication technique for PVDF-trFE films empowers future astronauts to design and manufacture piezoelectric sensors while in space, thereby significantly enhancing the affordability and sustainability of deep space exploration missions.

High-performance solid-state Li-ion batteries enabled by homogeneous, large-area ferroelectric PVDF-TrFE solid polymer electrolytes via horizontal centrifugal casting method

Solid polymer electrolytes (SPEs) have emerged as promising alternatives for enhancing the safety features of lithium-ion batteries (LIBs) while remaining compatible with established LIB manufacturing processes. However, a persistent challenge has been the relatively limited yield achieved via traditional fabrication techniques such as solution casting and doctor blade methods. In this study, we present a novel strategy to produce extensive and uniform films of solid polymer electrolytes using a ferroelectric polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) polymer. This approach employs horizontal centrifugal casting (HCC), a technique hitherto unutilized for SPE production. The substantial centrifugal forces generated during the HCC process yield SPE films characterized by uniform thickness across the surface and elevated ionic conductivity at ambient temperature. Compared to conventional solution casting techniques, the Li//Li cell featuring the SPE derived from HCC manifests stable electrochemical performance and increased cycle endurance. Additionally, a full cell incorporating a Li iron phosphate cathode displays consistent electrochemical behavior at room temperature. Notably, a 3 × 4 cm2 pouch cell maintains its performance attributes even under mechanical stress conditions such as folding and punching. These findings underscore the potential effectiveness of employing the HCC method in the development of high-performance SPE-based LIB systems.

Volumetric 3D‐Printed Piezoelectric Polymer Films

AbstractA novel additive manufacturing route using a tailored resin containing Poly(vinylidene fluoride) Trifluoroethylene (PVDF‐TrFE) to 3D print piezoelectric films is demonstrated. Piezoelectric films are printed within 2 seconds in a single step by simultaneously focusing initiating and inhibiting excitations within the liquid resin to locally confine the photochemical reaction. The printed films are patterned with an array of holes with a diameter of 30 µm and a pitch of 55 µm. The piezoelectric response is homogeneous across the film, indicating that the print pattern does not impact the PVDF‐TrFE microstructure. Although the printed films contain only a small volume fraction of PVDF‐TrFE (3 wt.%), their piezoelectric response (d33 = 20.3 pC/N) is comparable to the highest literature values reported for PVDF‐TrFE films. The printed PVDF‐TrFE films are predominantly β‐phase, and no electrical poling, post‐processing, piezoelectric or inorganic additives are used in the fabrication. Analysis using piezoresponse force microscopy (PFM) and scanning electron microscopy (SEM) reveals that the enhanced piezoelectric response is due to the preferential formation of oriented PVDF‐TrFE phases during printing. These results demonstrate how the dedicated design of photoactive resins in combination with volumetric additive manufacturing can be applied to rapidly fabricate functional 3D structures.

Surface potential modulation for improved mechanical energy harvesting and sensing in 3D printed biopolymer thermoelectret

This study presents the development of a special class of electret known as thermoelectret, made with polylactic acid (PLA), prepared via 3D printing technology followed by a heat-assisted corona discharged technique. We show that the bimodal surface polarity (i.e., ± 1 kV) is possible to achieve over the top and bottom surfaces of 3D printed PLA thermoelectret that enable a wide range of potential applications, such as mechanical energy harvesting to wearable biomedical sensors. Besides this, the enhanced surface potential leads to a giant longitudinal piezoelectric coefficient (d33) of 350 ± 15 pC/N, which is typically 10 times higher than the best-known piezoelectric polymer, polyvinylidene fluoride-trifluoro ethylene (PVDF-TrFE). To utilize this benefit, a 3D-printed thermoelectret-based mechanical energy harvester (3D-TEH) has been developed that delivers an outstanding power density of ⁓ 25 mW/m2, which makes it a suitable candidate for the self-power pressure sensor. As a proof of concept, we have demonstrated that 3D-TEH is capable of recording the bone-joints motions, coughing action, and human foot-pressure distribution that signify its potential application as a self-powered bio-medical sensor.

Ultrasound-Activated Piezoelectric Polyvinylidene Fluoride-Trifluoroethylene Scaffolds for Tissue Engineering Applications.

Severe peripheral nervous system (PNS) injuries have limited options for therapeutic solutions to regain functional recovery. This can be attributed in part to the lack of regeneration pathways promoted by recapitulating chemical, physical, and electrical cues to direct nerve guidance. To address this, we examined ultrasonic stimulation of a piezoelectric polyvinylidene fluoride-triflouroethylene (PVDF-TrFE) scaffold as a potentially clinically relevant therapy for PNS regeneration. Owing to the piezoelectric modality of PVDF-TrFE, we hypothesize that ultrasound stimulation will activate the scaffold to electrically stimulate cells in response to the mechanical deformation mediated by sound waves. Biocompatible PVDF-TrFE scaffolds were fabricated to be used as an ultrasound-activated, piezoelectric biomaterial to enhance cellular activity for PNS applications. NIH-3T3 fibroblasts were cultured on PVDF-TrFE nanofibers and stimulated with low-, medium-, or high-powered ultrasound. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays were performed on fibroblasts to measure the metabolic activity of the cells following stimulation. MTT assays showed that ultrasound-stimulated fibroblasts on PVDF-TrFE scaffolds had increased metabolic activity as power was increased, whereas on plain polystyrene, an opposite trend was observed where cells had a decreased metabolic activity with ascending levels of ultrasound power. Ultrasound-stimulated PVDF-TrFE nanofibers hold exciting potential as a therapy for PNS injuries by promoting increased metabolic activity and proliferation. The ability to noninvasively stimulate implantable piezoelectric nanofibers to promote mechanical and electrical stimulation for nerve repair offers a promising benefit to severe trauma patients.

Scaling relations of dynamic hysteresis in pristine and BiFeO3 particle embedded P(VDF-TrFE) flexible ferroelectric membranes

The domain reversal dynamics of the pristine and 10 wt. % BiFeO3 nanoparticle-embedded P(VDF-TrFE) (polyvinylidene fluoride-trifluoroethylene) flexible ferroelectric membranes were investigated. A scaling relation of A∝fαE0β relevant to the domain reversal dynamics was eventually determined. The pristine P(VDF-TrFE) flexible membrane takes the form of A∝f0.04077E00.39748 in stage III of high electric fields. Nevertheless, for BiFeO3-embedded P(VDF-TrFE) [BFO/P(VDF-TrFE)] flexible membranes, the relations are developed as A∝f−0.3326E02.74911 in the low electric fields of stage I and as A∝f0.04309E01.04872 in stage III separately. The negative α indicates that more and more domain reversal lags behind the alternating periodic electric field in stage I. Instead, in stage III, the positive α indicates that most domain reversals can occur anytime whatever the alternating speed of electric fields is. Analogously, the positive β indicates that at any selected frequency, domains can flip at an external electric field. Abnormally, for the pristine P(VDF-TrFE) membrane, the scaling relation in the first E0 stage is broken, reflecting only dielectric contributions this time. The dynamic scaling data are significant for the micromechanism accomplishments of copolymers and for the designs of flexible electric devices.

An airflow-driven system for scalable production of nano-microfiber wrapped triboelectric yarns for wearable applications

Nanofibers, with their large aspect ratio, high specific surface area, and high porosity, hold great promise for applications in textile materials, biomedicine, and smart wearables. Currently, the primary method for producing nanofibers is electrospinning. However, this method carries operational risks due to the use of high-voltage electrostatic fields, and it is not suitable for large-scale production due to low efficiency. To address these challenges, we propose an air-driven spinning system that combines solution blow spinning and vortex tubes for the scalable production of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) nano-microfiber wrapped conductive yarn. The airbrushing machine allows for high-speed production of PVDF-TrFE nano-microfibers through solution blow spinning, with a maximum production rate of approximately 36 ml/h. The vortex tubes apply rotation and twist to the core yarn using high-speed airflow to bond the nano-microfibers to core yarn. By optimizing the process, we achieve a tight integration between the outer layer of nano-microfibers and the inner layer of conductive core yarn, imparting water repellency, flexibility, washability, air permeability, and a certain level of abrasion resistance to the resulting yarn. We demonstrate the applications of this yarn as triboelectric nanogenerators, including energy harvesting and self-powered sensing. Furthermore, we employ this method to prepare stretchable self-generating triboelectric yarn. This air-driven spinning system overcomes the limitations of electrospinning, providing a scalable and efficient method for the production of nano-microfiber-wrapped yarns with various functional properties.

Piezoelectric PVDF-TrFE/PET Energy Harvesters for Structural Health Monitoring (SHM) Applications

This study presents a piezoelectric energy harvester made of poly(vinylidene fluoride-trifluoroethylene)/polyethylene terephthalate for use in structural health monitoring applications. The piezoelectric energy harvester was made of a layer of polyvinylidene fluoride-trifluoroethylene (PVDF/TrFE). In addition, PET sheets, double-sided micron-thick tapes, and PVDF-TrFE sheets were utilized in the fabrication of the device. The proposed device was characterized by measuring its output voltage and current. The output power of the harvester was sufficient to operate a MEMS pressure sensor under wind pressure, with a maximum current of 291.34 µA and a maximum voltage of 937.01 mV. The power value obtained was 272.99 µW.

Microstructure and mechanical properties of BT/PVTC composite ferroelectric thin films.

Ferroelectric ceramic polymer composites have become the preferred electrocaloric materials due to their light weight and high polarization strength. But the mechanical properties were desired to be improved. In this study, the polyvinylidene fluoride trifluoro ethylene chloride (PVTC) and barium titanate (BT) composites were prepared, and the microstructure and mechanical properties were investigated by molecular dynamics simulations and experiments. It was found that with the increase of BT ceramic content in the composites, the yield stress is significantly reduced, which can be reduced by 16.07%. By comparing with the experimental data, the agglomeration and stress mechanism of the composites were proposed. The microstructure of the composite was analyzed using radial distribution function, self-diffusion coefficient, and glass transition temperature. The agglomeration mechanism of the composite was revealed from the microscopic point of view, and the rationality of the agglomeration behavior was verified by experiments. The calculations were performed by Material Studio 2019 software and the COMPASS force field was adopted.

Wide-band electrical and electromechanical properties of polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) piezoelectric films using electro-acoustic reflectometry

Thin piezoelectric polymer films are used in increasingly more high frequency applications. However, they are not well characterized up to the gigahertz range. In this paper, polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) films are mechanically and electrically characterized using the electro-acoustic reflectometry (EAR) method from 20 MHz to 2 GHz. In addition to mechanical and electrical properties, nonuniform poling is detected in the tested PVDF-TrFE samples showing a larger piezoelectric constant in the middle of the film and thus generating even and odd resonance modes.

A Neuron‐Readable Artificial Photoreceptor Composed of Photodeformable Liquid Crystal Polymers and Piezoelectric Materials

AbstractArtificial photoreceptors are extensively developed to help the patients with serious eye diseases by converting light into electric signals. However, the existing systems still suffer from poor output signals, restricting signal transduction to cells. Here, a neuron‐readable artificial photoreceptor with significant voltage output is constructed by using photodeformable liquid crystal polymers (LCPs) and polyvinylidene fluoride trifluoroethylene (P(VDF‐TrFE)). The significant voltage output originates from light‐stress‐electricity conversion, where the photo‐induced stress is attributed to the free volume expansion of the photodeformable LCPs and subsequently converts them into strong electric signals by the P(VDF‐TrFE) layer. The photo‐induced open‐circuit voltage reaches up to 0.79 ± 0.02 V, which is, to the knowledge, 19 times higher than the maximum voltage (0.04 V) that has been reported to date. Hence, such artificial photoreceptor successfully transduces photo‐induced electric signals to cells and tissues, communicates with the neurons, and triggers spiking activities in blind retinas. Besides, visual image recognition is demonstrated in a pixelated matrix by analyzing electric signals of each unit. This artificial photoreceptor opens new opportunities for the combination of the photodeformability and piezoelectricity, providing an avenue to develop neuron‐readable artificial retinas and implantable sensors.

Alteration of membrane potential of head and neck cancer cells using a piezoelectric nanofiber interface.

Membrane potential (Vmem) is an electrical property associated with any cell, specific to its origin and function. These transmembrane voltage gradients have been established to control not only neural signaling via gap junctions, but also cell proliferation, migration, differentiation, and orientation in both excitable and non-excitable cells. The bioelectric state of cancer cells is different from that of healthy cells, causing a disruption in cell signaling pathways, affecting all three processes of carcinogenesis - initiation, promotion, and progression. More positively charged or depolarized Vmem correspond to more undifferentiated, proliferative, and stem-like cells. Understanding of the underlying bioelectric mechanisms and their disruption in cancer can be advanced by developing molecular tools capable of measuring and altering Vmem. Current gold standards include bio actuators, patch clamps, conductive polymers, and treatment with pharmacological drugs such as ivermectin. Biocompatible piezoelectric (PE) materials can alter the Vmem of cells by contact, without the use of transgenes. Here we introduce a PE polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) biomaterial interface capable of generating quantified electrical stimuli in response to mechanical deformation, thus altering resting Vmem of cells. PVDF-TrFE nanofibers seeded with Cal27 - oral squamous carcinoma cells (OSCC) were subjected to 1 cm mechanical stretch deformations at a frequency of 1 Hz for 3 minutes every 24 h. Results indicated significant increase in cell proliferation for treatment groups on days 3, 5, and 7 of culture as compared to controls. This platform can be further evolved to alter Vmem of cancer spheroids in 3D to better mimic the bioelectric state of cells in the tumor microenvironment (TME) and study subsequent alterations in signaling pathways.

The Effect of Electrospinning Parameters on Piezoelectric PVDF-TrFE Nanofibers: Experimental and Simulation Study

Polyvinylidene fluoride and its copolymers can be used as active materials for energy harvesting and environmental sensing. Energy harvesting is one of the most recent research techniques for producing stable electrical energy from mechanical sources. Polyvinylidene fluoride–trifluoroethylene (PVDF-TrFE) is applicable for sensors and self-powered devices such as medical implants and wearable electronic devices. The preparation of electrospun P(VDF-TrFE) nanofibers is of great interest for the fabrication of sensors and self-powered devices, nanogenerators, and sensors. In this regard, it is necessary to investigate the effects of various parameters on the morphology and piezoelectric output voltage of such nanofibers. In this study, we have examined the effect of concentration and feed rate on the nanofiber diameter. It has been found that by increasing the concentration and feed rate of the polymer solution, the diameter of the nanofibers increases. The experimental results and the finite element method (FEM) simulation have also shown consistency; when the nanofiber diameter increases, the output voltage of the nanofibers decreases. This behavior can be related to the strain reduction in the deformed nanofibers.

Flexible PVDF-TrFE Nanocomposites with Ag-decorated BCZT Heterostructures for Piezoelectric Nanogenerator Applications.

Flexible piezoelectric nanogenerators are playing an important role in delivering power to next-generation wearable electronic devices due to their high-power density and potential to create self-powered sensors for the Internet of Things. Among the range of available piezoelectric materials, poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)-based piezoelectric composites exhibit significant potential for flexible piezoelectric nanogenerator applications. However, the high electric fields that are required for poling cannot be readily applied to polymer composites containing piezoelectric fillers due to the high permittivity contrast between the filler and matrix, which reduces the dielectric strength. In this paper, novel Ag-decorated BCZT heterostructures were synthesized via a photoreduction method, which were introduced at a low level (3 wt %) into the matrix of PVDF-TrFE to fabricate piezoelectric composite films. The effect of Ag nanoparticle loading content on the dielectric, ferroelectric, and piezoelectric properties was investigated in detail, where a maximum piezoelectric energy-harvesting figure of merit of 5.68 × 10-12 m2/N was obtained in a 0.04Ag-BCZT NWs/PVDF-TrFE composite film, where 0.04 represents the concentration of the AgNO3 solution. Modeling showed that an optimum performance was achieved by tailoring the fraction and distribution of the conductive silver nanoparticles to achieve a careful balance between generating electric field concentrations to increase the level of polarization, while not degrading the dielectric strength. This work therefore provides a strategy for the design and manufacture of highly polarized piezoelectric composite films for piezoelectric nanogenerator applications.

Matrix-addressed crosstalk-free self-powered pressure sensor array based on electrospun isolated PVDF-TrFE cells

Flexible pressure sensor array has attracted much attention in wearable electronics, but still lacks self-power, high resolution, large-area fabrication, and low crosstalk. Herein, we present a self-powered pressure sensor array via patterned piezoelectric polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) nanofibrous. The PVDF-TrFE nanofibers were collected by patterned metal ground electrodes that isolated each piezoelectric cell. The isolated sensing cells can effectively reduce the crosstalk caused by additional deformation. The potential from individual cell is detected through the row+column electrode configuration to determine the corresponding pressure point and trajectory information. The as-fabricated pressure sensor array showed an excellent linear piezoelectric response (2.5 mV/kPa), a fast response time (5 ms), and good repeatability (25,000 cycles). Furthermore, our piezoelectric devices with constructed PVDF-TrFE layer are feasible in scaling up to a large-area sensor array. Accurate recognitions of the letter "h" trajectory tracking and tactile sensation by our self-powered tactile sensor array show potential applications in electronic skin and artificial intelligence. • The piezoelectric sensor array with isolated PVDF-TrFE cell is constructed to cancel out the voltage crosstalk. • The electrospinning is a versatile and low-cost method to produce self-patterned and polarized nanofibers. • The accurate trajectory recognition based on our sensor array is successfully demonstrated.

Piezoelectric performance improvement via macromolecular rearrangement

Because of their good flexibility and capacity to capture the dynamic mechanical energy by converting it into electrical signals, polymeric piezoelectric nanogenerators (PENGs) have broad application prospects in mechanical vibration detection and acquisition as sensors and self-powered systems. Here, a flexible PENG film based on hydroxypropyl cellulose (HPC) as the matrix, polyvinylidene fluoride (PVDF) as an auxiliary electrospinning reagent and BaTiO3 nanoparticles (NPs) as a piezoelectric nanofiller is constructed by electrospinning and post-treatments for macromolecule rearrangement and thus piezoelectricity enhancement. This PENG demonstrates a superior sensitivity (23.33 mV kPa−1) which is over 3.9 times those of the commercial PVDF and polyvinylidene fluoride-trifluoroethylene films. This performance enhancement is ascribed to the HPC dissolution and regeneration during post-treatments, resulting in the formation of outer wrappers around fibrils and thus an interconnected fibrous network with junction nodes between adjacent fibers for stress transfer efficiency. The partial crystal phase transformation of PVDF during film densification may also play a role in the increase of piezoelectricity. A series of practical application scenarios are established to demonstrate the highly promising potential of this fibril-based composite membrane for multifunctional force sensing and energy collection.

Integration of Screen Printed Piezoelectric Sensors for Force Impact Sensing in Smart Multifunctional Glass Applications

Screen printed piezoelectric polyvinylidene fluoride–trifluoro ethylene (PVDF–TrFE)‐based sensors laminated between glass panes in the temperature range 80–110 °C are presented. No degradation of the piezoelectric signals is observed for the sensors laminated at 110 °C, despite approaching the Curie temperature of the piezoelectric material. The piezoelectric sensors, here monitoring force impact in smart glass applications, are characterized by using a calibrated impact hammer system and standardized impact situations. Stand‐alone piezoelectric sensors and piezoelectric sensors integrated on poly(methyl methacrylate) are also evaluated. The piezoelectric constants obtained from the measurements of the nonintegrated piezoelectric sensors are in good agreement with the literature. The piezoelectric sensor response is measured by using either physical electrical contacts between the piezoelectric sensors and the readout electronics, or wirelessly via both noncontact capacitive coupling and Bluetooth low‐energy radio link. The developed sensor concept is finally demonstrated in smart window prototypes, in which integrated piezoelectric sensors are used to detect break‐in attempts. Additionally, each prototype includes an electrochromic film to control the light transmittance of the window, a screen printed electrochromic display for status indications and wireless communication with an external server, and a holistic approach of hybrid printed electronic systems targeting smart multifunctional glass applications.

All electrospun fabrics based piezoelectric tactile sensor

Tactile sensors have been widely used in the areas of health monitoring and intelligent human-machine interface. Flexible tactile sensors based on nanofiber mats made by electrospinning can meet the requirements of comfortability and breathability for wearing the body very well. Here, we developed a flexible and self-powered tactile sensor that was sandwich assembled by electrospun organic electrodes and a piezoelectric layer. The metal-free organic electrodes of thermal plastic polyurethane (PU) nanofibers decorated with multi-walled carbon nanotubes were fabricated by electrospinning followed by ultrasonication treatment. The electrospun polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) mat was utilized as the piezoelectric layer, and it was found that the piezoelectric performance of PVDF-TrFE nanofiber mat added with barium titanate (BaTiO3) nanoparticles was enhanced about 187% than that of the pure PVDF-TrFE nanofiber mat. For practical application, the as-prepared piezoelectric tactile sensor exhibited an approximative linear relationship between the external force and the electrical output. Then the array of fabricated sensors was attached to the fingertips of a glove to grab a cup of water for tactile sensing, and the mass of water can be directly estimated according to the outputs of the sensor array. Attributed to the integrated merits of good flexibility, enhanced piezoelectric performance, light weight, and efficient gas permeability, the developed tactile sensor could be widely used as wearable devices for robot execution end or prosthesis for tactile feedback.

Implantable acousto-optic window for monitoring ultrasound-mediated neuromodulation in vivo.

.SignificanceUltrasound has recently received considerable attention in neuroscience because it provides noninvasive control of deep brain activity. Although the feasibility of ultrasound stimulation has been reported in preclinical and clinical settings, its mechanistic understanding remains limited. While optical microscopy has become the “gold standard” tool for investigating population-level neural functions in vivo, its application for ultrasound neuromodulation has been technically challenging, as most conventional ultrasonic transducers are not designed to be compatible with optical microscopy.AimWe aimed to develop a transparent acoustic transducer based on a glass coverslip called the acousto-optic window (AOW), which simultaneously provides ultrasound neuromodulation and microscopic monitoring of neural responses in vivo.ApproachThe AOW was fabricated by the serial deposition of transparent acoustic stacks on a circular glass coverslip, comprising a piezoelectric material, polyvinylidene fluoride-trifluoroethylene, and indium-tin-oxide electrodes. The fabricated AOW was implanted into a transgenic neural-activity reporter mouse after open craniotomy. Two-photon microscopy was used to observe neuronal activity in response to ultrasonic stimulation through the AOW.ResultsThe AOW allowed microscopic imaging of calcium activity in cortical neurons in response to ultrasound stimulation. The optical transparency was over the visible and near-infrared spectra, and the ultrasonic pressure was 0.035 MPa at 10 MHz corresponding to . In anesthetized Gad2-GCaMP6-tdTomato mice, we observed robust ultrasound-evoked activation of inhibitory cortical neurons at depths up to .ConclusionsThe AOW is an implantable ultrasonic transducer that is broadly compatible with optical imaging modalities. The AOW will facilitate our understanding of ultrasound neuromodulation in vivo.

Fully Printed Flexible Piezoelectric Nanogenerators with Triethoxyvinylsilane (TEVS) Coated Barium Titanate (BTO) Nanoparticles for Energy Harvesting and Self‐Powered Sensing

AbstractThe improvement of wearable electronics is making energy harvesters appealing, as they lessen the requirement for regular recharge of wearable gadgets. In this work, fully printed, flexible piezoelectric nanogenerators (PENGs) with excellent performance are created using a 3D printing technology. This fully‐printing method is based on triethoxyvinylsilane (TEVS) coated barium titanate (BTO) nanoparticles, polyvinylidene fluoride‐co‐trifluoroethylene (PVDF–TrFE), and silver electrode for additive manufacturing. The organic vinyl silane (VS) functional groups, which form a strong bond between inorganic nanoparticles and polymer, contribute to the homogeneous dispersion of BTO nanoparticles in the matrix. Consquently, these fully printed VS–BTO/PVDF–TrFE PENGs outperform their untreated counterpart in terms of output voltage and power density, with a higher output voltage of 54 V even after 13 500 cycles and a higher power density of 28.5 µW cm−2. In practice, as‐printed devices may actively adapt to human movement and detect the pulse from multipoint mechanical activity identification. The fully printed PENGs developed in this work show excellent potential to be used in wearable electronics for a new generation of sensing applications.