Triboelectric nanogenerators (TENGs) offer a promising approach that surpasses the limitations of conventional energy harvesting systems by converting human biomechanical activity to therapeutic electrical stimulation. Herein, we designed a flexible TENG featuring multilayered biodegradable electrospun nanofibrous membranes of poly(lactic acid) (PLA) as the tribonegative layer and keratin/polyvinylpyrrolidone (Ker/PVP) as the tribopositive layer. Metal-organic frameworks (MOFs) and Ti3C2T x MXene/MOFs (MXOFs) were integrated within the PLA and Ker/PVP nanofibrous membranes, respectively, to enhance their triboelectrification properties and charge-trapping ability. The developed nanofibrous membranes were characterized using various morphological and structural analyses including scanning electron microscopy, atomic force microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and contact angle measurements, demonstrating the successful fabrication of uniform and bead-free nanofibrous membranes. Various TENG devices were designed and fabricated with varying MOF and MXOF contents (1, 2, 3, and 5% w/w). Following the optimization of both triboelectric layers, the enhanced TENG device demonstrated an open-circuit voltage density of 66 kV/m2 and a short-circuit current density of 470 mA/m2 with 2% w/w nanoparticle content. The developed TENG showed long-term durability upon application of the periodic force over a period of 1200 s. These findings provide a new and innovative pathway for the development of next-generation multifunctional TENGs for biocompatible energy harvesting applications.

In this study, the effects of halogen-free flame retardant additives aluminum hydroxide (ATH) and zinc borate (ZnB) on the mechanical and fire resistance properties of glass fiber-reinforced unsaturated polyester (GF/UP) composites were systematically investigated. ATH and ZnB additives (5

In this study, a biodegradable and sustainable piezoelectric–triboelectric hybrid nanogenerator (HENG) was designed and fabricated using cellulose nanofibrils (CNFs) as a nucleating agent and phycocyanin (PC), an algae-derived protein from Spirulina platensis, as the tribo-positive layer paired with poly(vinylidene fluoride) (PVDF) films. The investigation was conducted in two parts to investigate the effect of CNF incorporation into different layers. In the first part, CNFs were incorporated into the PVDF layer, whereas in second part incorporated into the PC layer. Electromechanical performance was characterized under periodic contact–separation motion. Even in the absence of nanofillers, the PVDF–PC pair exhibited efficient electromechanical behavior, generating an open-circuit voltage (Voc) of 84 V and a short-circuit current (Isc) of 87 µA. Upon CNF incorporation, the output was significantly enhanced. The highest performance was observed when CNFs were added to the PVDF layer (at 20 wt.

Wireless and self-powered systems for consumer electronics have been in a rising trend in recent years as a result of developments in alternative energy studies, unsustainable nature of fossil fuels, and environmental concerns. In this context, among alternative energy sources, piezoelectric, triboelectric, thermoelectric, pyroelectric, and electromagnetic conversion are the main mechanisms for energy generation in large and/or small scale applications. Piezoelectric devices are one of the most attractive systems among these for energy and sensing applications. Piezoelectric material-based mechanical, vibration, wind, sound, and even biomechanical energy harvesters have been produced by many researchers. In this section, the concept of piezoelectricity, piezoelectric energy harvesting theory, piezoelectric materials, and energy applications based on piezoelectric materials will be discussed.

ABSTRACT Fiber‐reinforced polymer composites are widely used in industries such as automotive, aerospace, and defense due to their exceptional properties. In the automotive sector, these composites are particularly required to exhibit high flame‐retardant characteristics. However, the flame‐retardant capabilities of conventional fiber‐reinforced polymer composites are often insufficient for applications demanding enhanced fire safety. This study systematically investigates the individual and combined effects of zinc borate (Z), aluminum hydroxide (A), and magnesium hydroxide (M) microparticles on the flame‐retardant and mechanical properties of glass fiber‐reinforced epoxy composites. In addition to single‐additive systems, multi‐component hybrid formulations incorporating Z, A, and M particles were developed to evaluate the efficacy of single versus multi‐component systems. During composite fabrication, flame‐retardant additives were incorporated into the epoxy matrix at various weight percentages and combinations, followed by lamination using the hand lay‐up method. Subsequently, horizontal burning and mechanical tests (flexural and impact) were conducted on composite specimens according to international standards. The unfilled (neat) composite exhibited the highest flexural and impact strength. As the additive content increased, particle agglomeration due to high surface energy promoted stress concentration sites, leading to a slight reduction in mechanical properties. Conversely, flammability tests revealed that microparticle reinforcement significantly reduced the horizontal burning rate. Specifically, specimens containing 20 wt.% flame‐retardant additives (20A, 20Z, 20M, 10A10Z, and Hybrid2) achieved burning rate reductions of 41.97%, 47.68%, 12.95%, 35.02%, and 23.20%, respectively, compared to the neat composite. Overall, single zinc borate formulations (20Z) demonstrated superior fire suppression efficiency compared to hybrid combinations, offering a practical optimization pathway for fire‐safe automotive composite structures.

In this study, the aim was to improve the interfacial properties of carbon fabric-epoxy matrix composites using MXene, a 2D material with superior characteristics, as a reinforcement. To achieve this, carbon fabrics were first surface-activated using concentrated nitric acid, followed by spraying a solution containing MXene in varying weight percentages (0.2

In this study, photovoltaic textile structures were obtained by applying organic solar cell materials to flexible structures and textiles. For this purpose, materials suitable for flexible structures were optimized as the bottom electrode (anode) to replace ITO (indium tin oxide), and the most efficient bottom electrode was used in solar cell fabrication. ITO-coated PET (polyethylene terephthalate), PET, and textile/PET carrier layers were used as flexible structures. The photovoltaic properties of the obtained flexible structures were compared with those of solar cells made from rigid layers such as FTO (fluorine doped tin oxide) coated glass and standard glass.

This study investigates the manufacturability and electromagnetic shielding effectiveness (EMI-SE) of Ti3C2Tx/ MXene-coated glass fabric laminated composites for aerospace applications. MXene-coated fabrics were produced using a dip-coating method. The effects of varying dipping counts (5 and 10) and different configurations of fabric arrangements on the EMI-SE of the composites in the X-band range (8.2-12.4 GHz) were investigated. Glass fabrics with 5 and 10 dips showed average surface resistances of 38.56 Omega/sq and 23.17 Omega/sq, respectively. In both the 5- and 10-dip composite sets, the total EMI-SE increased with the number of MXene-coated glass fabric layers in the composite. The 5MXC5 and 10MXC5 specimens, with conductive fabric in all layers, had average total shielding effectiveness (SET) of -18.75 dB and -23.21 dB, respectively. These values are 147.05 % and 205.80 % higher than the neat glass fiber-epoxy composite (C1). Flammability, bending, ILSS, and hardness tests were conducted on these composites. Increasing the MXene content reduced the burning rate, with 10MXC5 exhibiting a 26.31 % lower burning rate compared to C1. However, higher MXene content slightly decreased bending and ILSS values. Optical microscope examination of the fracture surfaces revealed that this decrease was due to delamination damage.

Textile-based electrodes are the most important components of wearable and portable supercapacitors. Ti3C2Tx MXene and reduced graphene oxide (rGO) have a great potential for the fabrication of high-performance textile supercapacitor electrodes. In this work, rGO was synthesized with the presence of cellulose nanocrystal (CNC) and Ti3C2Tx/rGO/CNC dispersions with different rGO/CNC contents were prepared. The plain-woven cotton fabrics were coated by homogenous Ti3C2Tx and Ti3C2Tx/rGO/CNC dispersions (5

The mechanical properties of polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and PLA/PETG structures manufactured using the multi-material additive manufacturing (MMAM) method were studied in this work. Material extrusion additive manufacturing was used to print PLA/PETG samples with various PLA and PETG layer numbers. By varying the top and bottom layer numbers of two thermoplastics, the effect of layer number on the mechanical properties of 3D-printed structures was investigated. The chemical and thermal characteristics of PLA and PETG were investigated using Fourier transform infrared spectroscopy and differential scanning calorimetry. Tensile and flexural strength of 3D-printed PLA, PETG, and PLA/PETG samples were determined using tensile and three-point bending tests. The fracture surfaces of the samples were evaluated using optical microscopy. The results indicated that multi-material part containing 13 layers of PLA and 3 layers of PETG exhibited the highest ultimate tensile strength (65.4 MPa) and a good flexural strength (91.4 MPa). MMAM was discovered to be a viable way for producing PLA/PETG materials with great mechanical performance.

Today a wide variety of wearable electronics are in our daily lives and their uses are increasing. The development of portable, flexible, lightweight, cost-effective, and stable devices that produce sustainable energy with renewable approaches in the field of wearable electronics, as in every field, is one of the important issues of today. According to their volume and weight, the use of nanofibers with high surface area in energy-generating devices may bring them advantages such as lightness and higher energy density. Therefore, in recent years, researchers have focused on the development of nanofiber-based nanogenerators that produce energy using mechanical energy in a sustainable and renewable way. In this paper, self-standing piezoelectric nanogenerator (PENG) fabrics were obtained by developing flexible composite poly(vinylidene fluoride) (PVDF) nanofiber yarns doped with zinc oxide (ZnO) nanoparticles at different rates to provide higher power output. It has been characterized from electromechanical, structural, and morphological aspects. The most successful self-standing PENG fabric obtained (at 5% ZnO loading) doubled the energy output of the fabric made from pure PVDF nanofiber yarn and provided a peak total power of 81 mu W and a power density of 30 mu W/cm(2). The present results open up the field for the development of PVDF/ZnO-based nanomats and their use in sensors and actuators in the healthcare and engineering industries.

Various methods are applied in order to improve the mechanical properties of concrete and to provide ductility. The most common method is the addition of fiber to cementitious systems. The fibers used in cementitious systems are divided into two categories: artificial and natural. Natural fibers are preferred due to their lower production cost, lower environmental impacts such as lower carbon emissions and fossil fuel consumption, biodegradability, lower density and ease of manufacturing. On the other hand, graphene-derived materials have been proven to improve the mechanical and interface properties between fiber and matrix. In this study, the effect of surface treatment of jute fibers with various chemical treatments and graphene oxide coating on the mechanical and some durability performances of concrete mixtures was investigated. For this purpose, the surface of jute fibers was roughened with graphene oxide coating. Within the scope of the experimental study, different fiber concrete mixtures were prepared by adding jute fibers of 30 and 50 mm length to the mixture at 0.25 and 0.5 % of the total volume in addition to the fiber-free control mixture. The fiber was used in 2 different ways, both without any treatment and by coating the surface with graphene oxide. Slump tests were performed on the concrete mixtures produced. The 28-day hardened concrete specimens were tested for compressive strength, flexural strength, modulus of elasticity, ultrasonic pulse velocity and depth of water penetration under pressure. The resistance of the concrete specimens at 300 and 600 degrees C high temperatures and after 300 cycles of freeze-thaw was determined by examining their compressive strength. In addition, the microstructural properties of the jute fiber specimens were examined using Scanning Electron Microscopy (SEM).

Increasing mechanical properties without losing electrical properties is of great importance for the development of advanced electronic textile products and their use in different areas. In this study, a cost-effective and facile preparation of MXene/cellulose nanocrystal-coated cotton fabrics by drop-casting was carried out to investigate electrical and mechanical properties of plain woven cotton fabrics. MXene (Ti3C2Tx) and cellulose nanocrystal dispersions of MXene (5 wt.

MXene, a 2D transition metal carbide and nitride with graphene-like layered structures, has become one of the preferred choice for nano-reinforcement in polymer matrix composites in recent years due to its outstanding properties such as specific surface area, excellent thermal and mechanical characteristics, and high conductivity. In this study, the glass fiber-epoxy laminated composites reinforced with Ti3C2Tx-MXene (M)/ functionalized-MXene (FM) were produced using the hand lay-up procedure followed by vacuum bagging process. The effects of varying filler amounts (0.125, 0.25, 0.375, and 0.5%) on the mechanical and flame retardancy properties of glass fiber-epoxy composites were examined. In both M and FM reinforced composites, the highest values of mechanical strengths were obtained with a 0.25% filler, while a decrease in mechanical strengths was observed beyond this reinforcement amount. The 0.25wt% FM-reinforced composite exhibited 19.21%, 27.55%, and 12.40% higher tensile, flexural, and interlaminar shear strengths (ILSS) than the pristine glass fiber-epoxy composite (N-C). Post-test analysis revealed the presence of matrix cracks, fiber breakage, and fiber pull-out damages were observed on the surfaces of composite samples. The flame retardant properties of the composites were enhanced with the addition of MXene reinforcement, and 0.5FM-C exhibited 25.50% lower burning rate than N-C.

Conducting polymers (CPs) are polymers that attract great attention due to their very good electrical and optical properties. However, their mechanical strength and processability are far from the necessary conditions for many applications. On the other hand, polyvinyl chloride (PVC), which is the third most produced polymer in terms of quantity, is a common polymer type whose properties can be changed with many additives and thus can be used in many different fields. The resulting blended films find application in areas such as sensors, supercapacitors, electromagnetic shielding, and antistatic coating. In this section, first of all, the electrical, optical, and mechanical properties of CP/PVC mixtures will be examined. Then, the applications of CP/PVC mixtures will be mentioned.

With the increase in environmental pollution, studies on the use of sustainable resources are increasing day by day. For this purpose, the use of natural fiber-reinforced polymer composites is encouraged in many areas such as automotive, transportation, construction, and home textiles. However, they are flammable and therefore seriously threaten the safety of people and property. Various flame retardant additives have been used to improve the flame retardancy properties of these composites. In this study, silicon dioxide (SD) and zinc borate (ZB) microparticles in different weight percentages (3, 5, 7, and 10%) were reinforced to give flame retardant properties to jute-epoxy composites. In addition, composites containing both SD and ZB microparticles were produced and they were labeled as HB. Then, thermal conductivity, flammability, water absorption, and mechanical properties of these composites were investigated. The burning rate of the composites decreased as the amount of microparticle increased. 5ZB5SD, including %5 SD and %5 SD microparticles, showed 36.60% less burning rate than the neat jute-epoxy composite. 5ZB showed 10.84% higher tensile strength than the neat jute-epoxy. The impact strength of the specimens increased with the increase in the filling ratio, and 5ZB5SD showed approximately 2.50 times the impact strength of the jute-epoxy composite.

Studies on energy generation devices for necessary energy needs have been an increasing trend all over the world as the kinds and quantities of consumer gadgets have increased. Researchers have been studying nanogenerators for the last 15 years in response to this demand. The three main reasons for these studies are increased output power, application to consumer items, and mechanical stability. Hybrid nanogenerators, on the other hand, are a method of combining at least two energy conversion mechanisms, hence reducing the need for a single conversion mechanism. In this context, while triboelectric-piezoelectric combination hybrid nanogenerators are the most popular hybrid nanogenerator class, they have several drawbacks, such as non-compact and unstable structures. As a result, for the first time, a small hybrid polymer-nanofiberbased hybrid nanogenerator concept with high output voltage and current is disclosed in this study. A hybrid nanofibrous structure was created using an electrospinning apparatus with double and triple nozzles. As a result of the periodic-compression test, the resulting nanogenerators produced a maximum voltage density of 5350 V/m2 and a current density of 5454 A/m2. By hand tapping, the resulting master unit was able to light up 119 LEDs and charge a commercial capacitor up to 0.9 V.