Advancing Dielectric and Ferroelectric Properties of Piezoelectric Polymers by Combining Graphene and Ferroelectric Ceramic Additives for Energy Storage Applications

Synergy of Hybrid Fillers for Emerging Composite and Nanocomposite Materials-A Review

Nanocomposites with polymer matrix provide tremendous opportunities to investigate new functions beyond those of traditional materials. The global community is gradually tending toward the use of composite and nanocomposite materials. This review is aimed at reporting the recent developments and understanding revolving around hybridizing fillers for composite materials. The influence of various analyses, characterizations, and mechanical properties of the hybrid filler are considered. The introduction of hybrid fillers to polymer matrices enhances the macro and micro properties of the composites and nanocomposites resulting from the synergistic interactions between the hybrid fillers and the polymers. In this review, the synergistic impact of using hybrid fillers in the production of developing composite and nanocomposite materials is highlighted. The use of hybrid fillers offers a viable way to improve the mechanical, thermal, and electrical properties of these sophisticated materials. This study explains the many tactics and methodologies used to install hybrid fillers into composite and nanocomposite matrices by conducting a thorough analysis of recent research. Furthermore, the synergistic interactions of several types of fillers, including organic-inorganic, nano-micro, and bio-based fillers, are fully investigated. The performance benefits obtained from the synergistic combination of various fillers are examined, as well as their prospective applications in a variety of disciplines. Furthermore, the difficulties and opportunities related to the use of hybrid fillers are critically reviewed, presenting perspectives on future research paths in this rapidly expanding area of materials science.

Dynamic Pluronic F127 Crosslinking Enhancement of Biopolymeric Nanocomposites for Piezo-Triboelectric Single-Hybrid Nanogenerators and Self-Powered Sensors

Biomechanical and nanomechanical energy harvesting systems have gained a wealth of interest, resulting in a plethora of research into the development of biopolymeric-based devices as sustainable alternatives. Piezoelectric, triboelectric, and hybrid nanogenerator devices for electrical applications are engineered and fabricated using innovative, sustainable, facile-approach flexible composite films with high performance based on bacterial cellulose and BaTiO₃ , intrinsically and structurally enhanced by Pluronic F127, a micellar cross-linker. The voltage and current outputs of the modified versions with multiwalled carbon nanotube as a conductivity enhancer and post-poling effect are 38 V and 2.8 µA cm^-2 , respectively. The multiconnective devices' power density can approach 10 µW cm^-2 . The rectified output power is capable of charging capacitors, driving light-emitting diode lights, powering a digital watch and interfacing with a commercial microcontroller board to operate as a piezoresistive force sensor switch as a proof of concept. Magnetoelectric studies show that the composites have the potential to be incorporated into magnetoelectric systems. The biopolymeric composites prove to be desirable candidates for multifunctional energy harvesters and electronic devices.

Increased dielectric performance of PVDF-based composites by electrochemical exfoliated graphite additives

Adding conductive graphene into polyvinyliden1 fluoride (PVDF) is an effective method to improve the dielectric properties. However, the high conductivity and uniform distribution of graphene in PVDF matrix still meet challenges. In this work, electrochemical exfoliated graphite (EEG) with good conductivity and solution dispersion is used to prepare PVDF/EEG films. By this method no specific conditions are needed such as reduction or hot press. The dielectric properties and flexibility of PVDF/EEG films of different concentrations of EEG are investigated. Especially, when EEG content is 2.6 wt%, composite film has a high dielectric constant of 86 and a low dielectric loss of 0.9 (100 Hz). Simultaneously, the tensile strength of the film was up to 55.1 MPa. The preparation method is simple and convenient, and the obtained material has high dielectric constant and tensile strength. This method paves the way for the application of flexible electronic sensing equipment.

Mechanochemical Synthesis of BaTiO3 Powders and Evaluation of Their Acrylic Dispersions

Barium titanate is a ferroelectric perovskite with unique electric properties; therefore, it is widely applied in the fabrication of inorganic coatings or thin films, capacitors, or in the production of devices for energy storage and conversion. This paper describes the mechanochemical synthesis of BaTiO3 from BaO and TiO2 using a ball mill. XRD analysis allowed concluding that barium titanate was formed after 90 min of mechanochemical grinding. It was also proved by spectroscopic analysis and the band corresponding to Ti-O vibrations on obtained Fourier Transform Infrared (FT-IR) spectra. The specific surface area of obtained powder was 25.275 m2/g. Next, formed perovskite was dispersed in an acrylic poly(ethylene glycol) (superabsorbent polymer suspension, SAP) suspension prepared using microwave radiation. Final suspensions differed in the concentration of SAP applied. It was proven that the increase of SAP concentration does not affect the acidity of the suspension, but it does increase its dynamic viscosity. A sample with 83 wt.% of SAP reached a value of approximately 140 mPa∙s. Dispersions with higher values of SAP mass fraction exhibited lower sedimentation rates. Molecules such as SAP may adsorb to the surface of particles and thus prevent their agglomeration and make them well monodispersed. Based on the performed experiments, it can be concluded that acrylic poly(ethylene glycol) suspension is a suitable fluid that may stabilize barium titanate dispersions.

Magneto-Electric Effect on Guided Waves in Functionally Graded Piezoelectric⁻Piezomagnetic Fan-Shaped Cylindrical Structures

Functionally graded piezoelectric–piezomagnetic (FGPP) material simultaneously consists of piezomagnetic and piezoelectric phases, which are able to convert energy among mechanical, electric, and magnetic fields. The magneto-electric effect on waves in FGPP fan-shaped cylindrical structures is studied by exploiting the double Legendre orthogonal polynomial method. By means of the Heaviside function, the initial conditions are brought into wave motion equations. Dispersion properties, electric and magnetic potential, and the Poynting vector are calculated. Subsequently, the effect of the graded variation and geometric size on wave characteristics is analyzed. The FGPP fan-shaped cylindrical structures are of complex geometrical shape and material inhomogeneity, so their influences on the magneto-electric effect are the focus of discussion. Results reveal that the cut-off frequencies have a negative relationship with the cross-section area of the structure. The magneto-electric effect could be adjusted via altering the geometric size of the cross-section. These results can be utilized to design and optimize piezoelectric–piezomagnetic fan-shaped transducers.