Agglomeration Of Nanofillers Research Articles

Experimental Investigation of Mechanical Properties and Morphology of Ramie, Bamboo, and Ramie-Bamboo Hybrid Composites with Silicon Carbide and Alumina Nano-Fillers

Abstract The study explores the mechanical and morphological studies of ramie, bamboo, and hybrid ramie-bamboo composites with silicon carbide (SiC) and alumina (Al2O3) nano-fillers. The composites were fabricated using the hand-layup method followed by compression moulding. Mechanical characteristics such as tensile, flexural, impact, and hardness were investigated as per the ASTM standards. Surface characterization was performed using scanning electron microscopy (SEM) to understand the surface characteristics and failure behavior of composites. Experimental results indicated that the maximum tensile strength (50.16 MPa), impact strength (6.30 kJ/m2), and hardness (79.4) were obtained for the ramie-bamboo hybrid composite as compared to the other composites. The average flexural strength (101.4 MPa) of the pure ramie composite was superior to that of other composites. SEM micrographs revealed good fiber-matrix bonding in the hybrid composites. Ramie-bamboo hybrid composites with nano-fillers showed lower strength values due to the agglomeration of nano-fillers.

Emerging two dimensional MXene for corrosion protection in new energy systems: Design and mechanisms.

With the development of new and clean energy (offshore wind power, fuel cells, aqueous zinc ion batteries, lithium-ion batteries, etc.), the corrosion and security problems in special environments of the new energy system have attracted much attention. Corrosion protection on the metals applied in new energy system can reduce the economic loss, security risk, and energy consumption, as well as guarantee the efficiency of energy system. Traditional coatings face challenges in agglomeration of nano fillers, structural control, environmental issues, and poor conductivity, which limits the applications. With features in controllable surface chemistry and composition, rich surface terminations, better conductivity than graphene oxide, high aspect-ratio, strong impermeability, and low friction coefficient, the two-dimensional (2D) MXene presents potential for applications in corrosion protection in new energy systems. Despite progress has been made in the MXene for corrosion protection, there is still a lack of comprehensive review regarding the design and mechanisms of anti-corrosive MXene-based materials for corrosion protection in new energy system. In this review, a brief induction of MXene and the specially four corrosive environments (offshore wind power at deep sea, bipolar plates in PEMFC environments, zinc anode in AZIBs, and current collectors in Li-ion battery) are presented. Importantly, the design strategies and mechanisms of the MXene-based anti-corrosive coatings on metals used in the special environments are discussed in detail. Finally, the challenges and research trends in the MXene-based coatings for new energy systems are prospected. This review provides further understanding of corrosion in new energy and would expand the application prospects of MXene.

Enhancing the Filler Utilization of Composite Gel Electrolytes via In Situ Solution-Processable Method for Sustainable Sodium-Ion Batteries.

The composite gel electrolyte (CGE), which combines the advantages of inorganic solid-state electrolytes and solid polymer electrolytes, is regarded as the ultimate candidate for constructing batteries with high safety and superior electrode-electrolyte interface contact. However, the ubiquitous agglomeration of nanofillers results in low filler utilization, which seriously reduces structural uniformity and ion transport efficiency, thus restricting the development of consistent and durable batteries. Herein, a solution-processable method to in situ construct CGE with high filler utilization is introduced. The homogeneous metal-organic framework fillers contribute to uniform ionic and electronic filed distribution, realizing a stable electrode-electrolyte interface. Consequently, the CGE with high filler utilization achieves an ultra-long lifespan of 10000 cycles with a capacity retention of 80.2%. This work provides guidance for constructing high-performance CGEs in electrochemical energy-storage devices.

Long-term corrosion protection of reinforcing bars via a self-responsive coating incorporating ZrP functional fillers

The conventional coating of reinforcing bars exhibits inadequate anti-corrosion efficacy stemming from a non-specific, blind protection mechanism, poses a threat to the durability of concrete. We devised a novel self-responsive functional filler, L-arginine (LA) intercalated zirconium phosphate (LCZrP), synthesized via an intercalation reaction. This innovative filler was seamlessly integrated into an epoxy (EP) resin matrix, yielding a smart anticorrosive coating that harmoniously combines active and passive corrosion protection strategies. The integration of LCZrP within the coating matrix serves a trifecta of purposes: it extends the corrosion propagation path, effectively disperses nanofiller agglomeration, and enhances interfacial adhesion with the epoxy coating. Critically, the controlled release of corrosion inhibitors from the interlayer further fortifies the coating's resistance to corrosion, imparting a multi-layered protective shield. After enduring a 60-day immersion in a simulated concrete pore solution, the LCZrP/EP coating demonstrated exceptional durability, maintaining a low-frequency impedance modulus value consistently within the range of 4.27×1010 to 5.12×1010 Ω·cm2, marking a remarkable 34-fold enhancement over the performance of the epoxy coating alone. This breakthrough underscores the LCZrP/EP coating's potential as a groundbreaking solution for reinforcing bar protection in concrete, harnessing the complementary strengths of epoxy resin's physical barrier, the impermeability of two-dimensional lamellar structures, and the proactive release of corrosion inhibitors to forge a robust, multi-faceted passivation layer.

Melamine Network as a Solution for Significant Enhancement of the Mechanical, Adsorptive, and Surface Properties in a Novel Carbon Nanomaterial-Silica Aerogel Composite.

Silica aerogels exhibit exceptional characteristics such as mesoporosity, light weight, high surface area, and pore volume. Nevertheless, their utilization in industrial settings remains constrained due to their brittleness, moisture sensitivity, and costly synthesis procedure. Several studies have proved that adding nanofillers, such as carbon nanotubes (CNT) or graphene nanoplatelets (GNP), can improve the mechanical strength of the aerogels. The incorporation of nanofillers is often accompanied by agglomeration and pore blockage, which, in turn, deteriorates the surface area, pore volume, and low density. Including flexible melamine foam (MF) as a scaffold for the silica aerogel and nanofiller composite can prevent the restacking of the nanofillers through π-π interaction, hence maintaining the incredible properties of aerogels and improving their mechanical properties. CNT, GNP, and the polymeric silica precursor, polyvinyltrimethoxysilane (PVTMS), were added to a MF, at varying concentrations, to fabricate the MF-aerogel nanocomposites. Surfactant and sonication were utilized to ensure a homogeneous dispersion of the nanofillers in the system. The presence of MF prevented the agglomeration of nanofillers, resulting in lower density and relatively higher surface properties (SBET up to 929 m2·g-1 and pore volume up to 4.34 cc·g-1). Moreover, the MF-supported samples could endure 80% strain without breakage and showed an outstanding compressive strength of up to ∼20 MPa. These aerogel nanocomposites also demonstrated an excellent volatile organic compound (∼2680 mg·g-1) and cationic dye adsorption (∼10 mg·g-1).

Ultra-low detection limit self-sensing nanocomposites with self-assembled conductive microsphere arrays for asphalt pavement health monitoring

Accurately monitoring micro-level strain within pavements poses a significant challenge in contemporary road engineering, limiting the effectiveness of early-stage pavement health diagnostics. Addressing this critical gap, this study introduces an innovative ultra-low detection limit sensor, specifically designed for intricate pavement health monitoring. It pivots on the unique structural design of a well-ordered 3D conductive network, where the self-assembly effect of microsphere arrays ingeniously mitigates the prevalent issue of nanofiller agglomeration within polymer matrices. The study highlights the significant role of carbon nanotubes (CNTs) length in shaping the structure of conductive networks, revealing that while longer CNTs lead to less uniform microsphere assemblies, they significantly enhance the bridging effect crucial for conductive pathways. To balance these traits, surface chemical modifications were strategically applied, effectively enhancing microsphere organization and dispersion, thereby elevating the conductive and sensing performance. The optimized sensor stands out for the ultra-low detection limit of 0.0005% (5 uε), significantly surpassing those of current strain sensors. Moreover, it exhibits remarkable sensitivity, evidenced by a gauge factor of 13.2, along with swift response and recovery times of 19 ms and 26 ms respectively, and impressive durability, enduring over 100,000 loading-unloading cycles. Field tests under diverse vehicular loads and speeds further validate the sensor's accuracy in capturing dynamic responses within pavement structures, a key factor in proactive pavement maintenance and management. Hence, this advancement shows promise in contributing to the development of safer and more resilient road networks, playing a beneficial role in the significant progress of intelligent transportation and sustainable infrastructure management.

Experimental and simulation studies of hybrid MWCNT/montmorillonite reinforced FDM based PLA filaments with multifunctional properties enhancement

AbstractThe recent investigation in the development of novel multifunctional thermoplastic polymer‐based filaments has contributed to the extensive use of hybrid nanofiller combinations. Montmorillonite (MMT) and multiwalled carbon nanotubes (MWCNT) are nanofillers with exceptional properties and their combination tends to induce synergistic property enhancement on incorporation within the polymer matrix. In our current study, CNT‐MMT hybrid has been synthesized, while XRD, FTIR, Raman, and TEM confirmed its successful formation. Different wt% (0.5–2) of CNT‐MMT were reinforced into polylactic acid (PLA) matrix and their inclusive properties were analyzed in order to obtain percolation threshold concentration. The tensile strength analysis of PLA with 1% CNT‐MMT displayed 47.4% enhancement as compared to virgin PLA, while DMA analysis confirmed storage modulus enhancement. These results were also corroborated with simulation studies using ANSYS. However, with 2% addition of CNT‐MMT, the tensile strength reduced due to nanofiller agglomeration, which was also verified with SEM studies. The thermal and electrical properties of nanocomposites also augmented considerably due to CNT‐MMT reinforcement with electrical conductivity of PLA + 1% CNT‐MMT enhanced by 9 orders of magnitude. These multifunctional filaments tend to produce refined 3D printed structure using FDM and could be harnessed toward advanced 3D printing applications for commercial devices.Highlights Different wt% of CNT‐MMT were reinforced into polylactic acid (PLA) matrix and their inclusive properties were analyzed. The tensile strength analysis of PLA with 1% CNT‐MMT displayed 47.4% enhancement as compared to virgin PLA, simulation studies using ANSYS confirmed it. The thermal and electrical properties of nanocomposites also augmented considerably due to CNT‐MMT reinforcement. These multifunctional filaments tend to produce refined 3D printed structure using FDM. This could be harnessed toward advanced 3D printing applications for commercial devices.

Experimental investigation of the effect of functionalized graphene on the creep behavior of epoxy

The objective of the current work was to investigate the creep behavior of functionalized graphene (f-GNF)-epoxy nanocomposite. Time and temperature-dependent mechanical behaviors were investigated by performing creep tests at three different stress levels and two different temperatures. Graphene produced by the electric arc discharge method was functionalized with Triton X-100 by a non-covalent method. Then, f-GNF-epoxy nanocomposites are produced by using the Three Roll Milling (3RM) method to eliminate nanofiller agglomeration. By performing quasi-static compression tests, stress levels for creep tests are determined as 50, 100, and 200 MPa to guarantee the viscoelastic deformation regime, around yield, and the viscoplastic deformation regime, respectively. The results indicate significant creep resistance in the nanocomposite with 0.1 wt% f-GNF. Depending on temperature and stress level, the effect of f-GNF is more pronounced at higher stresses and temperatures. f-GNFs have a significant effect on inhibiting the mobility of polymer chains, resulting improvements in the creep modulus. This indicates that thermally activated processes controlling the creep rate are in part inhibited by the presence of f-GNF. In the creep tests carried out for 2 h, a maximum improvement of 85% was observed in the creep modulus of epoxy-nanocomposite compared to pure epoxy at room temperature.

Screen Printing of Surface-Modified Barium Titanate/Polyvinylidene Fluoride Nanocomposites for High-Performance Flexible Piezoelectric Nanogenerators.

Piezoelectric energy harvesters are appealing for the improvement of wearable electronics, owing to their excellent mechanical and electrical properties. Herein, screen-printed piezoelectric nanogenerators (PENGs) are developed from triethoxy(octyl)silane-coated barium titanate/polyvinylidene fluoride (TOS-BTO/PVDF) nanocomposites with excellent performance based on the important link between material, structure, and performance. In order to minimize the effect of nanofiller agglomeration, TOS-coated BTO nanoparticles are anchored onto PVDF. Thus, composites with well-distributed TOS-BTO nanoparticles exhibit fewer defects, resulting in reduced charge annihilation during charge transfer from inorganic nanoparticles to the polymer. Consequently, the screen-printed TOS-BTO/PVDF PENG exhibits a significantly enhanced output voltage of 20 V, even after 7500 cycles, and a higher power density of 15.6 μW cm−2, which is 200 and 150% higher than those of pristine BTO/PVDF PENGs, respectively. The increased performance of TOS-BTO/PVDF PENGs is due to the enhanced compatibility between nanofillers and polymers and the resulting improvement in dielectric response. Furthermore, as-printed devices could actively adapt to human movements and displayed excellent detection capability. The screen-printed process offers excellent potential for developing flexible and high-performance piezoelectric devices in a cost-effective and sustainable way.

A novel shape memory polymer composites with grafted hydroxyapatite nanoparticles for high strength and stiffness applications

AbstractShape memory polymer (SMP) composites have evolved uniquely, employing nanoscale fillers, which add multifunctionality to the basic resin. In this work, the effect of inorganic, grafted hydroxyapatite (g‐HAp) nanoparticles on the dynamic (mechanical), thermo‐mechanical and microstructural properties of copolymer, based on diurethane dimethacrylate (DUDMA), (t‐butyl acrylate (tBA), and crosslinker poly(ethylene glycol) dimethacrylate (PEGDMA), has been investigated. The agglomeration of nanofillers is limited by using PEG dimethacrylate monomer to graft HAp nanoparticles. Importantly, it is observed that mixing DUDMA in (tBA + PEGDMA) has improved the Young's Modulus of SMP composite to 5.4 GPa at RT (comparable to aircraft grade resin) with a glass transition temperature (Tg) of 55°C. Tensile stress is high as 51.46 MPa with improved strain at failure from 0.07% to 0.05%. The elongation strains of 4–8% are achieved, which provide the required strain compatibility to develop aerospace SMPs as well as SMP composites for structural and bio‐medical applications.

Investigation of flexural properties of epoxy composite by utilizing graphene nanofillers and natural hemp fibre reinforcement

This study aims to determine the optimum reinforcement required to attain the best combination of flexural strength of modified green composites (graphene oxide + hemp fibre reinforced epoxy composites) for potential use in structural applications. An attempt was also made for the combination of graphene and hemp fibres to enhance load-bearing ability. The infusion of hemp and graphene was made by the weight of the base matrix (epoxy composite). Results showed that graphene reinforcement at 0.4 wt.% of matrix showed load-sustaining capacity of 0.76 kN or 760 MPa. In the case of hemp fibre reinforcement at 0.2 wt.% of the matrix, infusion showed enhanced load-bearing ability (0.79 kN or 790 MPa). However, the combination of graphene (0.1 wt.% graphene nanofillers) and hemp (5 wt.% hemp fibre) indicated a load-sustaining ability of 0.425 kN or 425 MPa, whereas maximum deflection was observed for specimen with hemp 7.5 % + graphene 0.2 % with 1.9 mm. Graphene addition to the modified composites in combination with natural fibres showed promising results in enhancing the mechanical properties under study. Moreover, graphene-modified composites exhibited higher thermal resistance compared to natural fibre reinforced composites. However, when nanofiller reinforcement exceeded a threshold value, the composites exhibited reduced flexural strength as a result of nanofiller agglomeration.

Analysis of Epoxy Nanocomposites Characteristics by Impedance Spectroscopy

AbstractThe research work is carried out to analyse the electrical characteristics of glass fiber reinforced epoxy composites with the addition of multiwall carbon nanotubes and graphene nanoplatelets. The dispersion of 2wt.% multi walled carbon nanotubes(MWCNT) and 1‐3wt.% graphene nanoplatelets (GNP) into the epoxy resin is assisted with high shear mechanical mixing followed by ultrasonication. The epoxy‐filler mixture is transferred into temperature‐controlled resin bath for pultrusion process. The pultrusion process helps to resolve major issues like poor dispersion and agglomeration of nanofillers in epoxy resin. The XRD and SEM analysis indicates that fillers are dispersed homogeneously in the epoxy matrix. The electrical conductivity (σ) and impedance (Z) are studied in the frequency range (10 Hz‐8 MHz) with the variation in temperature (over 25 °C‐150 °C). It is observed that the addition of two conductive nanofillers results in a synergistic effect at the percolation threshold, and the conductivity value increases by few orders due to the formation of a number of conductive paths in the composite. The complex impedance decreases with increase in frequency for the composites except for the sample with 3wt.% GNP and 2wt.% MWCNT indicating the semiconducting behaviour. The complex impedance plot is characterized by the appearance of a single semi‐circular arc whose radii of curvature decreases with an increase in temperature, indicating the existence of electrical relaxation phenomena.

Recent advances of thin film nanocomposite membranes: Effects of shape/structure of nanomaterials and interfacial polymerization methods

The emergence of nanomaterial arouses the development of thin film nanocomposite (TFN) in membrane separation technology. The incorporation of nanofillers into the TFN selective layer enhanced the membrane pure water permeability (PWP) with a slight improvement or even deterioration on the salt rejection. This trade-off is mainly due to the agglomeration of nanofillers, poor interactions between nanofiller and polymer matrix, and the formation of defects in the TFN selective layer. Hence, it is critical to explore and understand the fundamental knowledge of the effects of the shape/structure of nanofillers or interfacial polymerization methods on TFN membranes. This review summarizes the emerging development of TFN membranes incorporated with porous and non-porous nanofillers in the past 5 years, followed by the highlights of the effects of shape/structure of nanofillers on the TFN selective layer. Different shape/structure of nanofillers will influence the transport mechanisms of water molecules and solutes, resulting in a significant change in separation performance. Moreover, various modified interfacial polymerization methods to improve the dispersibility of nanofillers or fabrication of defect-free selective layers are discussed. The challenges and perspectives for TFN membranes are also highlighted.

Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

Rapid Preparation of MWCNTs/Epoxy Resin Nanocomposites by Photoinduced Frontal Polymerization.

Due to their excellent mechanical and thermal properties and medium resistance, epoxy/carbon nanotubes and nanocomposites have been widely used in many fields. However, the conventional thermosetting process is not only time- and energy-consuming, but also causes the agglomeration of nanofillers, which leads to unsatisfactory properties of the obtained composites. In this study, multi-walled carbon nanotubes (MWCNTs)/epoxy nanocomposites were prepared using UV photoinduced frontal polymerization (PIFP) in a rapid fashion. The addition of MWCNTs modified by a surface carboxylation reaction was found to enhance the impact strength and heat resistance of the epoxy matrix effectively. The experimental results indicate that with 0.4 wt % loading of modified MWCNTs, increases of 462.23% in the impact strength and 57.3 °C in the glass transition temperature Tg were achieved. A high-performance nanocomposite was prepared in only a few minutes using the PIFP approach. Considering its fast, energy-saving, and environmentally friendly production, the PIFP approach displays considerable potential in the field of the fast preparation, repair, and deep curing of nanocomposites and coatings.

Surface Modifications of Nanofillers for Carbon Dioxide Separation Nanocomposite Membrane

CO2 separation is an important process for a wide spectrum of industries including petrochemical, refinery and coal-fired power plant industries. The membrane-based process is a promising operation for CO2 separation owing to its fundamental engineering and economic benefits over the conventionally used separation processes. Asymmetric polymer–inorganic nanocomposite membranes are endowed with interesting properties for gas separation processes. The presence of nanosized inorganic nanofiller has offered unprecedented opportunities to address the issues of conventionally used polymeric membranes. Surface modification of nanofillers has become an important strategy to address the shortcomings of nanocomposite membranes in terms of nanofiller agglomeration and poor dispersion and polymer–nanofiller incompatibility. In the context of CO2 gas separation, surface modification of nanofiller is also accomplished to render additional CO2 sorption capacity and facilitated transport properties. This article focuses on the current strategies employed for the surface modification of nanofillers used in the development of CO2 separation nanocomposite membranes. A review based on the recent progresses made in physical and chemical modifications of nanofiller using various techniques and modifying agents is presented. The effectiveness of each strategy and the correlation between the surface modified nanofiller and the CO2 separation performance of the resultant nanocomposite membranes are thoroughly discussed.

Effects of cellulose nanofibrils/graphene oxide hybrid nanofiller in PVA nanocomposites

NCF/GO hybrid nanofillers with excellent UV-shielding properties were prepared by using TEMPO-oxidized nanocellulose fibrils (NCF) and graphene oxide (GO) as raw materials; different mass ratios of NCF to GO (2: 1, 4: 1, 8: 1, and 16: 1) were used. The NCF and GO were then combined and used as a hybrid filler to study the synergistic effects on polyvinyl alcohol (PVA) nanocomposites. With 5% hybrid nanofiller, the UV-shielding performance of the PVA/NCF/GO composite film was higher than 90%. The tensile strength and Young's modulus of the PVA/CG-2 composite film increased by 74.5% and 278.0%, respectively, and the water absorption decreased by 59%. Moreover, the thermal stabilities of the nanocomposites also improved. This synergistic effect improved the performance of the hybrid nanofiller by avoiding the agglomeration of nanofillers in the polymer matrix and improving the homogeneity of the dispersion. The synergistic effect between the fillers provides a new idea for the preparation of novel multifunctional nanocomposites.

Preparation of SiO2 grafted polyimidazole solid electrolyte for lithium-ion batteries

Solid electrolytes have emerged as a promising alternative to liquid electrolytes for application in solvent-free lithium rechargeable batteries. Composite polymer electrolytes based on polymer and nanoparticle exhibit acceptable ion conductivity due to the interaction between nanofillers and polymer. However, the application of composite polymer electrolytes is hindered by the agglomeration of nanofillers at high concentration. Herein, in this study, the polymer electrolytes with branched polyimidazole were synthesized by radical polymerization based on functionalized SiO2 nanoparticles and imidazole monomers. Different from the reported methods of blending ceramic particles with polymers, we introduce an in situ synthesis of branched polymer electrolyte based on functionalized SiO2 nanoparticles. The stronger chemical interactions between SiO2 nanospheres and polymer chains could significantly suppress the aggregation of the nanoparticles and improve temperature stability. Among all of the electrolyte films, SiO2-MOBIm6-BF4 shows the best ion conductivity of 5.96 × 10−5 S cm−1 at 25 °C and the value reaches to 9.54 × 10−4 S cm−1 at 95 °C. This is mainly due to the long methylene chain increasing the flexibility of the chain segment and the molecular mobility, which is benefit to lithium-ion transportation. The electrochemical stabilization window can reach 4.85 V at room temperature, and the LiFePO4/SiO2-MOBIm6-BF4/Li battery was assembled with the electrolyte based on SiO2-MOBIm6-BF4. The first discharge capacity can reach 158.3 mAh g−1, and the batteries show good cycle performance.

Hierarchically architected polydopamine modified BaTiO3@P(VDF-TrFE) nanocomposite fiber mats for flexible piezoelectric nanogenerators and self-powered sensors

Flexible piezoelectric nanogenerators (FPENGs) have attracted a great attention owing to their promising applications in harvesting mechanical energy and driving portable devices. To develop high-performance FPENGs, the significant relationship among material, structure and performance inspired us a rational design of FPENGs from Pdop-BaTiO3@P(VDF-TrFE) nanocomposite fiber mats with a hierarchically architected microstructure. In contrast with previous approaches, the polydopamine (Pdop) modified barium titanate (BaTiO3, BT) nanoparticles have been anchored onto the surface of electrospun poly (vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) fibers to fabricate hierarchical micro-structured membrane in this study, which not only effectively avoids the agglomeration of nanofillers but also enhances the density of interfaces in the nanocomposites. As a result, the as-fabricated FPENGs show a significantly enhanced output of 6 V and 1.5 μA as compared to the PENG with only P(VDF-TrFE) membrane (1.25 V and 0.6 μA). Furthermore, output voltage of the new FPENGs is 40%–68% higher than that of composite membranes with nanoparticles at the interior of nanofibers. The improved output of the PENG is attributed to the high density of interfaces in the hierarchical microstructure and the corresponding enhancement of dielectric response. Then, electric performance of FPENGs was investigated in terms of force, frequency and load resistance. Finally, the FPENG was employed to efficiently detect human body movements as self-powered sensors. The hierarchical nanocomposite membrane designed in this study provides an effective approach for developing mechanical energy harvesters, wearable sensor network and self-powered devices.

Vibration analysis of fluid-conveying multi-scale hybrid nanocomposite shells with respect to agglomeration of nanofillers

The vibration problem of a fluid conveying cylindrical shell consisted of newly developed multi-scale hybrid nanocomposites is solved in the present manuscript within the framework of an analytical solution. The consistent material is considered to be made from an initial matrix strengthened via both macro- and nano-scale reinforcements. The influence of nanofillers’ agglomeration, generated due to the high surface to volume ratio in nanostructures, is included by implementing Eshelby-Mori-Tanaka homogenization scheme. Afterwards, the equivalent material properties of the carbon nanotube reinforced (CNTR) nanocomposite are coupled with those of CFs within the framework of a modified rule of mixture. On the other hand, the influences of viscous flow are covered by extending the Navier-Stokes equation for cylinders. A cylindrical coordinate system is chosen and mixed with the infinitesimal strains of first-order shear deformation theory of shells to obtain the motion equations on the basis of the dynamic form of principle of virtual work. Next, the achieved governing equations will be solved by Galerkin’s method to reach the natural frequency of the structure for both simply supported and clamped boundary conditions. Presenting a set of illustrations, effects of each parameter on the dimensionless frequency of nanocomposite shells will be shown graphically.