Incorporation of barium titanate nanoparticles in piezoelectric PVDF membrane

Enhancing output efficiency in self-powered hybrid nanogenerators with micro-pyramid surface design using ceramic/polymer film for flexible wearable electronic devices

Self-powered sensors are increasingly valued for their eco-friendly and energy-efficient design, making them ideal for sustainable applications. As global energy demand rises and carbon emissions increase, there is a shift toward renewable energy sources like solar and wind. Advanced sustainable energy devices, such as piezoelectric and triboelectric nanogenerators, show promises for capturing untapped energy, supporting the development of portable, green devices. While commercialization of triboelectric materials is limited, they hold strong potential for large-scale energy harvesting. This study investigates how tailored surface topography can enhance the electrical output of a hybrid nanogenerator. We developed a hybrid piezoelectric and triboelectric nanogenerator (HBNG) using a BaTiO3-PDMS composite (containing 10-20 vol% barium titanate in polydimethylsiloxane). Micron-sized pyramid structures of 20% BT/PDMS were created on the film through optical lithography, while scanning electron microscopy and X-ray diffraction were used to assess the composite's crystal structure and phase characteristics. Altering the film's surface morphology led to substantial improvements in electrical performance, with voltage increasing from 28 V in the pristine film to 92 V in the micro-pyramid patterned film, and current rising from 2.7 μA to 11.0 μA. The enhanced power density and cyclic test suggests that surface topography optimization is highly effective, supporting long-term cyclic operation, and energy storage in capacitors. This work highlights the potential of surface-engineered nanogenerators in advancing sustainable, self-powered technologies.

Participation of Polymer Materials in the Structure of Piezoelectric Composites

This review explores the integration of polymer materials into piezoelectric composite structures, focusing on their application in sensor technologies, and wearable electronics. Piezoelectric composites combining ceramic phases like BaTiO3, KNN, or PZT with polymers such as PVDF exhibit significant potential due to their enhanced flexibility, processability, and electrical performance. The synergy between the high piezoelectric sensitivity of ceramics and the mechanical flexibility of polymers enables the development of advanced materials for biomedical devices, energy conversion, and smart infrastructure applications. This review discusses the evolution of lead-free ceramics, the challenges in improving polymer-ceramic interfaces, and innovations like 3D printing and surface functionalization, which enhance charge transfer and material durability. It also covers the effects of radiation on these materials, particularly in nuclear applications, and strategies to enhance radiation resistance. The review concludes that polymer materials play a critical role in advancing piezoelectric composite technologies by addressing environmental and functional challenges, paving the way for future innovations.

Succulent inspired grown g-C3N4@lithium sodium niobate for supercapacitors and piezo-tuned electrochemical potential controlled smart electromagnetic shielding management

A synchronous way of energy generation and storage in a single portable device is in high demand for the development of high-end electromagnetic interference (EMI) free modern electronics. Thus, this study highlights the devising of a piezoelectrically self-chargeable symmetric supercapacitor (PSCS) device using a polyvinyl alcohol (PVA)/succulent inspired grown g-C3N4@lithium sodium niobate (GNLNN)/potassium hydroxide (KOH) based piezo separator with GNLNN electrode. The GNLNN electrode exhibits a surface capacitive controlled specific capacitance of 503 F g-1. The PSCS device exhibits an energy density of 15.3 W h kg-1 and a power density of 4.2 kW kg-1 with an impressive capacitive retention capability of 93.2% after 6000 cycles of charging-discharging. The PSCS device can be charged up to 393 mV within 180 s under 14.2 N of cyclic pressing by human finger imparting. The fabricated PSCS device was also investigated for self-charging potential regulated smart EMI shielding applications. The smart PSCS device achieves an 88.3 dB increment from 40.9 dB of EMI shielding under charging from 0 mV to 300 mV. The increased charging potential of the PSCS device enhances the destructive interference and leads to boosted absorption and decreased reflection of incident EM radiation.

Investigation of Wettability, Thermal Stability, and Solar Behavior of Composite Films Based on Thermoplastic Polyurethane and Barium Titanate Nanoparticles

Herein, composite films were produced by incorporating different amounts (1, 3, 5, and 7%) of barium titanate nanoparticles into the thermoplastic polyurethane matrix using a solution casting method. This study examined the impact of the presence and concentration of a barium titanate additive on morphologic properties, mechanical performance, thermal stability, solar behavior, and wettability of produced film samples. The films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, scanning electron microscope, ultraviolet-visible near-infrared spectrophotometer, water contact angle, and tensile strength measurements. In the present study, the mass loss of samples containing 7% barium titanate was 24% lower than that of the pure polyurethane reference. The increase of barium titanate rate added to polyurethane enhanced the solar reflectance property of the films, including the near-infrared region. As a prominent result, the transmittance value decreased significantly compared to the reference in the ultraviolet region, and it dropped to 3% for the highest additive concentration. The contact angle values of polyurethane films increased by 11-40% depending on the barium titanate addition ratio. The nano additive also positively affected the mechanical performance of the reference polyurethane film by slightly increasing the tensile strength values.

A tough and piezoelectric poly(acrylamide/N,N-dimethylacrylamide) hydrogel-based flexible wearable sensor

A flexible, tough, highly transparent and piezoelectric polyacrylamide hydrogel was fabricated induced by blue light photocuring, with camphorquinone/diphenyliodonium hexafluorophosphate (CQ/DPI) as the blue light initiator, acrylamide (AM) and N,N-dimethylacrylamide (DMAA) as monomers, polyethylene glycol diacrylate (PEGDA) as the crosslinker, lecithin as the dispersant, and BaTiO3 as the piezoelectric material. Various performance tests were carried out on the hydrogel, and the results showed that lecithin enhances the dispersion of BaTiO3 within the system and improves the tensile properties (>100% strain) of the hydrogel, and the addition of PEGDA not only improves the photopolymerization performance of the hydrogel, but also significantly improves its fracture strength (∼0.3 MPa). In addition, BaTiO3 enables the resultant hydrogels to show excellent conductivity (>1.5) and stable response to strain. The assembled hydrogel sensor shows a sensitive response to human joint activities, which is expected to be applied in self-powered sensors and energy collection.

Boosting Demulsification and Antifouling Capacity of Membranes via an Enhanced Piezoelectric Effect for Sustaining Emulsion Separation

Traditional superwettable membranes for demulsification of oil/water emulsions could not maintain their separation performance for long because of low demulsification capacity and surface fouling during practical applications. A charging membrane could repel the contaminants for a while, the charge of which would gradually be neutralized during the separation progress. Here, a superhydrophilic piezoelectric membrane (SPM) with sustained demulsification and antifouling capacity is proposed for achieving prolonged emulsion separation, which is capable of converting inherent pulse hydraulic filtration pressure into pulse voltage. A pulse voltage up to -7.6 V is generated to intercept the oil by expediting the deformation and coalescence of emulsified oil droplets, realizing the demulsification. Furthermore, it repels negatively charged oil droplets, avoiding membrane fouling. Additionally, any organic foulants adhering to the membrane undergo degradation facilitated by the generated reactive oxygen species. The separation data demonstrate a 98.85% efficiency with a flux decline ratio below 14% during a 2 h separation duration and a nearly 100% flux recovery of SPM. This research opens new avenues in membrane separation, environmental remediation, etc.

Small Channels Assembled by Multilayer ZIF-8 in Nanocomposite Membranes for Filtration of Ofloxacin in Water

Metal-organic framework (MOF)-based hybrid membranes still face many unsolved difficulties in the field of liquid separation, with a reliable production technique standing out, in particular, for the water-stable MOF membranes. In this study, zeolitic imidazolate framework-8 (ZIF-8) with acceptable water stability, favorable polymer affinity, and high selectivity was meticulously grafted on commercial poly(vinylidene fluoride) (PVDF) via substrate carboxylation-assisted etching and then overlaid onto PVDF to fabricate a novel hybrid membrane by a layer-by-layer self-assembly method. The optimal membrane manufacturing conditions, including assembly time (10 min), Hmim/Zn2+ molar ratio (8:1), and optimal layer number (three layers), were thoroughly investigated for cutting-off ofloxacin in water filtration. Under low pressure, a nanofiltration scale permeability of about 199.2 L m-2 h-1 MPa-1 and 97.9% rejection of ofloxacin were obtained in bench-scale tests based on the synergistic effect of the Donnan effect and steric hindrance. More significantly, the resulting hybrid membrane demonstrated excellent hydrophilicity, high antifouling, and mechanical and repeatability performances, suggesting promising application possibilities in real-world wastewater filtering settings.

Piezoelectric Polyvinylidene Fluoride Membranes with Self-Powered and Electrified Antifouling Performance in Pressure-Driven Ultrafiltration Processes

Electroactive membranes have the potential to address membrane fouling via electrokinetic phenomena. However, additional energy consumption and complex material design represent chief barriers to achieving sustainable and economically viable antifouling performance. Herein, we present a novel strategy for fabricating a piezoelectric antifouling polyvinylidene fluoride (PVDF) membrane (Pi-UFM) by integrating the ion-dipole interactions (NaCl coagulation bath) and mild poling (in situ electric field) into a one-step phase separation process. This Pi-UFM with an intact porous structure could be self-powered in a typical ultrafiltration (UF) process via the responsivity to pressure stimuli, where the dominant β-PVDF phase and the out-of-plane aligned dipoles were demonstrated to be critical to obtain piezoelectricity. By challenging with different feed solutions, the Pi-UFM achieved enhanced antifouling capacity for organic foulants even with high ionic strength, suggesting that electrostatic repulsion and hydration repulsion were behind the antifouling mechanism. Furthermore, the TMP-dependent output performance of the Pi-UFM in both air and water confirmed its ability for converting ambient mechanical energy to in situ surface potential (ζ), demonstrating that this antifouling performance was a result of the membrane electromechanical transducer actions. Therefore, this study provides useful insight and strategy to enable piezoelectric materials for membrane filtration applications with energy efficiency and extend functionalities.