Flexible Polymer Nanocomposites Research Articles

Studying the structural, thermal, mechanical, and dielectric features of PVA/iron oxide@SiO2 polymer nanocomposites for electrical applications

Fe3O4@SiO2 (FS) nanocomposite was synthesized through the co-precipitation method and utilized as a filler material in the polyvinyl alcohol (PVA) matrix to obtain PVA/iron oxide@silica Fe3O4@SiO2 (PFS) films. This study presents the synthesis and characterization of flexible polymer nanocomposites comprising polyvinyl alcohol (PVA) matrices embedded with iron oxide @ silica. Through the analysis of the composite, we observed a significant enhancement in the thermal stability of the nanocomposites with increasing Fe3O4@SiO2 content. X-ray photoelectron spectroscopy (XPS) spectra have been used to provide more information about the chemical state and electronic structure of the polymer film. Dielectric spectroscopy revealed notable improvements in electrical properties, including increased real electric modulus and permittivity. Mechanical investigation showed an improvement in the tensile strength, meanwhile, Young's modulus has improved from 341.2 to 1789.8 MPa, indicating that (PVA) and FS successfully complexed and interacted strongly. These findings underscore the potential of these nanocomposites for high-performance applications in energy storage devices and other fields requiring robust dielectric materials.

Collegial effects of CeO2/SiC nano-fillers on dielectric, thermal, impedance and conductivity behavior of PVDF-HFP matrix for flexible energy storage applications

ABSTRACT In the current study, novel Poly(vinylidene fluoride-co-hexafluoropropylene)/Cerium oxide/Silica carbide (PVDF-HFP/CeO2/SiC) flexible polymer nanocomposites were synthesized by solution casting technique. Structural changes involved in the composite formation between nano-fillers and host polymers were analyzed by X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. SEM results confirm the homogeneous dispersion of nano-fillers (CeO2 & SiC) within the host polymer. Thermogravimetric analysis (TGA) was used to identify the thermal stability of the polymer nanocomposite with about 56% of residual residue for increased nano-fillers loading. Tauc plots confirm that the energy band gap of pristine host polymer decreased with the incorporation of nano-fillers. The dielectrics, impedance, and AC conductivity studies were investigated in temperature ranging from 50°C to 150°C and the frequency range between 50 Hz and 10 MHz measured by an impedance analyzer. As a function of nano-filler loading, the nanocomposites show a significant increase in the dielectric constant (ε′ = 272.92, 50 Hz, 50°C) with low dielectric loss (tan(δ) = 1.98, 50 Hz, 150°C) values. Impedance and the AC conductivity results suggested that addition of nano-filler decreases the impedance and improves the AC conductivity value from 1.67 × 10−4 S/m for pristine PVDF-HFP to 1.44×10−3S/m for 15% SiC. These results justify the material being efficiently applicable for flexible energy storage applications.

Nanocomposites comprising PVA/CMC matrix and CNTs/Fe2O3 nanohybrid: A comparative investigation of structural, optical, electrical, and dielectric properties as an application in advanced electrochemical and optoelectronic devices

This work addresses the fabrication of innovative flexible polymer nanocomposite films for electrochemical products made of poly (vinyl alcohol) (PVA), carboxymethyl cellulose (CMC), multi-walled carbon nanotubes (CNTs), and hematite (α-Fe2O3) nanoparticles (NPs) as nanohybrid. The PVA/CMC-CNTs/Fe2O3 nanocomposite films were characterized using various approaches. The PVA/CMC blend polymer matrix shows significant improvements in terms of amorphous nature with the CNTs/Fe2O3 nanofiller content, resulting in an exceedingly flexible polymer backbone and with higher ionic conductivity of the PVA/CMC-CNTs/Fe2O3 nanocomposites films, as reported by the XRD examination. The nanoparticle surfaces and the blend matrix exhibit a significant interaction, as seen by the FTIR spectra. To learn more about how CNTs/Fe2O3 NPs affect the optical characteristics of the PVA/CMC, its optical characteristics were examined. The absorption edge appeared to migrate towards lower photon energy sides upon the addition of CNTs/Fe2O3 NPs to the PVA/CMC matrix. The Eg (direct and indirect) of pure PVA/CMC was considerably decreased from 5.12 to 3.55 eV and 4.23 to 3.01 eV respectively by adding 3.5 wt% of CNTs/Fe2O3 NPs. The results proved the influence of the nanofiller on the host polymer's decreased band gap energy. The blend nanocomposite had a substantially higher AC conductivity compared with the blend, and the PVA/CMC-3.5%CNTs/Fe2O3 nanocomposite had the highest electrical conductivity. It was discovered that while the dielectric loss and dielectric constant increased with the high content of nanoparticles, they reduced with increasing frequency. These findings demonstrated that the produced films had undergone substantial changes, which allows for the use of flexible films made of PVA/CMC-CNTs/Fe2O3 in a variety of electrochemical and optoelectronic applications.

Synthesis, structural characterization and optical studies of Fe2O3 nanoparticles based polymeric materials for flexible electronic devices

In this work, a thin film containing a flexible polymer nanocomposite of iron oxide (Fe2O3) and poly(4-chloroaniline) P(4-ClAni) was successfully synthesized using the green polymerization fabrication method. To confirm the effective synthesis of the P(4- ClAni)/Fe2O3 nanocomposite, the XRD, SEM, and FTIR analyses were used. The SEM pictures revealed that the nanocomposite contain Fe2O3 nanoparticles distributed throughout the polymer matrix. The optical absorbance of the P(4-ClAni) and P(4-ClAni)/Fe2O3 films was measured at room temperature using a UV-vis spectrophotometer from 190 to 1150 nm. The optical properties of P(4-ClAni)/Fe2O3 films were calculated using Tauc's relation. The Urbach energy of the P(4-ClAni) increases from 0.96 eV to 1.65 eV, 1.73 eV, and 1.86 eV, respectively, when mixed with 2%, 4%, and 6% of Fe2O3. On the other hand, the band gap energy of P(4-ClAni) decreases from 3.57 eV to 3.39 eV, 3.07 eV, and 2.84 eV, respectively, with the addition of 2%, 4%, and 6% Fe2O3. Based on the results of this study, the composite P(4-ClAni)/Fe2O3 sheets can be used for flexible electronic devices.

Influence of SrTiO3/Fe2O3 nano-fillers assisted PVDF-HFP polymer nanocomposite films on dielectric, impedance, and conductivity studies for energy storage applications

abstract In recent years, electronic devices with trendy flexibility and compatibility have become the competitive alternative to conventional electronics. In the present work, flexible polymer nanocomposite films composed of poly(vinylidene fluoride-co-hexafluoropropylene), iron oxide, and strontium titanate (PVDF-HFP/SrTiO3/Fe2O3) were synthesized by the solution-casting method. The formation and structural features of this composite material have been analyzed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric (TGA), and SEM. SEM results confirm the homogeneous dispersion of SrTiO3 and Fe2O3 within the host polymer. The uniform dispersion of the embedded metal species enhances the dielectric values up to 462 on optimization with infused rigidity. The impedance studies of PVDF-HFP/SrTiO3/Fe2O3 were performed in the temperature region of 50–150 °C at various frequencies ranging from 50 Hz to 10 MHz and the AC conductivity studies suggested that synthesized polymer nanocomposite shows higher conductivity with the maximum conductivity value was 8.20 × 10−3S/m. Polymer nanocomposite films with large dielectric constant and minimum dielectric loss are highly recommendable for flexible energy storage applications. Also, rapid development of novel material for flexible electronics is in great demand, which suggests it is an alternate source for future energy storage application.

Improved dielectric properties of Sago Starch-Sodium Alginate (SS-SA) blend embedded with Cuc-Ags nanoparticles

Flexible polymer nanocomposites (NCs) based on Sago Starch-Sodium alginate (SS-SA) embedded Cu–Ag core-shell nanoparticles (Cuc-Ags NP) have been synthesized by solution casting approach. The structural and morphological properties of prepared NCs were investigated by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Field emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM) and Fourier Transform Infra-Red (FTIR) spectroscopy. The appearance of peaks in XRD spectra and lattice fringes in SAED pattern corresponding to Ag NP confirmed the core-shell architecture of Cuc-Ags NP, and the average crystallite size (calculated from XRD data) comes out to be 18.92 ± 0.16 nm. The interactions occurring between host matrix and NP have been confirmed using FTIR spectroscopy. The Cuc-Ags@SS-SA NC film exhibits superior tensile strength and Young's modulus as compared to pristine SS-SA film. The dielectric analysis revealed the highest dielectric constant for SS-SA matrix doped with 2.0 wt% Cuc-Ags NP (160.2 at RT) which is six times than that of pristine (at f = 50 Hz) and increases to 396.3 at 333 K. The Cole-Cole plots of Cuc-Ags@SS-SA NCs suggest the poly-dispersive nature of NC. The relaxation time (τ) decreases with increasing temperature and concentrations of Cuc-Ags NP in SS-SA. Such NCs with high ε′ and low ε" values have widespread applications as charge storage capacitors in flexible electronic devices.

Flexible and luminescent polymer nanocomposite films (YPO4:Pr3+/ polystyrene): Investigation of structural, morphological and photoluminescence properties for solid-state lighting applications

Luminescent polymer films are promising for future optoelectronic devices owing to their ease of synthesis, tunable properties and flexibility. The present work reports on the fabrication of YPO4:Pr3+/polystyrene based flexible and luminescent nanocomposite (NC) films followed by an investigation of their structural, morphological and photoluminescence properties for their potential applications in optical devices. NC films were successfully prepared by direct solution mixing of YPO4: Pr3+ (0.1, 2 at. %) luminescent nanoparticles (NPs) and polystyrene (PS). X-ray diffraction (XRD) analysis of NC films revealed an improvement in crystallinity upon increasing YPO4: Pr3 NPs doping into PS films. The emission spectra of the pure and YPO4:Pr3+/PS NC films under UV excitation at 223 nm showed the same features with a broad emission band in the 280–400 nm region. However, an increase in emission intensity, and absence of interconfigurational emission characteristic of the YPO4: Pr3+ NPs were observed in UV region, due to the strong absorption band of PS in this region. Upon doping, YPO4:Pr3+ NPs were found to reduce their intrinsic luminescence emission from interconfigurational transitions of Pr3+ ions. However, it was dominated by an orange-red luminescence of 1D2→3H4 transition, while, no emission was observed for the PS film owing to its transparency in the visible region. The fluorescence decay times of 1D2→3H4 in the NC films were shorter as compared to those of the original NPs. Chromatic coordinates and correlated color temperature indicated that the YPO4:Pr3+/PS NC films are promising polymer-phosphors for lighting applications.

Synthesis of flexible polymer nanocomposites based on methyl cellulose/copper oxide with desired dielectric properties for electrical applications

Herein, flexible MC/CuO composite consisting of methyl cellulose (MC) and copper oxide (CuO) were successfully fabricated by casting solution technique. The synthesized films were characterized by XRD, FTIR, and EDX methods, which confirm the successful preparation of the composite MC/CuO. Moreover, SEM images are investigated homogenous distribution of CuO in MC. The modulus, conductivity, and impedance of MC and CuO films were measured in frequency 50 Hz to 5 × 105 Hz. The addition of CuONPs to MC films induces a significant improvement in the permittivity due to the high level of scission. The conductivity is raised from 0.08 × 10−6 S/cm for MC to 6.77 × 10−6 S/cm for MC/9%CuO, and the dielectric constant raised from 6.32 to 70.6 at frequency of 100 Hz. The energy density is increased for MC from 2.79 × 10−5 J/m3 to 18.5 × 10−5 J/m3 and to 31.2 × 10−5 J/m3 by enhancing CuO content from 3% to 9% respectively. The barrier potential energy Wm was lowered from 0.58 eV for MC to 0.38 eV and to 0.36 eV after the increases CuO content from 3% to 9%. This results confirmed an improvement in the characteristics of MC/CuO films to be applied these films in a variety of industrial devices, including batteries and super-capacitors.

Impact of BaTiO3 on the structural, optical, and nuclear radiation shielding parameters of poly(methyl methacrylate) nanocomposites as transparent shielding material

Six weight percentages (0, 2, 5, 10, 15, and 20 wt(%)) of barium titanate BaTiO3 were doped as a nanoparticle in poly(methyl methacrylate) PMMA and their optical and nuclear radiation shielding properties were investigated. The XRD patterns, FTIR spectra and SEM images confirmed that the nanocomposite films were successfully prepared. The pure PMMA sample demonstrated a significant degree of transparency, approximately 90%. The inclusion of BaTiO3 resulted in a significant reduction in the optical bandgap while maintaining a moderate transmittance level of approximately 40% at a concentration of 10 wt (%). The direct and indirect band gap energy of PMMA were decreased from 4.81 eV to 4.62 eV–1.64 eV and 1.09 eV, respectively, after doping with 20 wt(%) BaTiO3 nanoparticles. The refractive index of the investigated samples was determined using various approaches and seen to increase after nanofiller addition. Seven energy lines, from Eu-152, Cs-137, Na-22 and Ra-226 radioactive gamma ray sources, were used to deduce the gamma ray shielding parameters of the prepared samples. Also, three neutron energy ranges were used to measure the macroscopic cross-sections for the investigated samples. The results showed good agreement between measured values of mass attenuation coefficients and those calculated by WinXCOM computer program. Furthermore, the optimal weight percentage of BaTiO3 in PMMA for attenuation of all examined gamma ray energies was 10 wt (%), whereas it was 15 wt (%) for the investigated three neutron energy ranges. In other words, a novel flexible, transparent and non-toxic polymer nanocomposite shielding material is presented and the samples containing 10–15 wt(%), demonstrates improved radiation attenuation.

Hybrid GO/TiO2 nanoparticles reinforced NaAlg/PVA blend: Nanocomposites for high‐performance energy storage devices

AbstractIn this study, novel flexible polymer nanocomposite films formed of polyvinyl alcohol (PVA), sodium alginate (NaAlg), titanium dioxide (TiO2) and graphene oxide (GO) as nanofiller are fabricated by using casting method. The PVA/NaAlg‐GO/TiO2 nanocomposite films are characterized using various techniques. The synergistic effects of GO/TiO2 on the electrical, dielectric properties, and the energy density efficiency of PVA/NaAlg blend have been investigated in the range of frequency from 10 Hz to 7 MHz. The XRD data showed that the intensity of the PVA/NaAlg‐GO/TiO2 nanocomposites films decrease with nanofiller concentration. The FTIR spectroscopy provides proof that the complex formed. The optical studies were carried out using UV–Vis. spectroscopy. The energy bandgap values of PVA/NaAlg‐GO/TiO2 nanocomposite films were calculated using Tauc's plot. It is shown that the host matrix's Eg value decreases from 4.97 to 4.29 eV for direct transitions and from 4.37 to 2.29 eV for indirect transitions. The electrical and dielectric parameters of the nanocomposites showed that the maximum electrical properties were observed for the composite with 8 wt% loading of GO/TiO2. The σdc increased from 2.45 × 10−9 to 5.02 × 10−7 S cm−1. In addition, frequency exponent S decreased from 0.82 to 0.54. These findings demonstrated that there are significant modifications in the fabricated samples, which open the road for utilizing the PVA/NaAlg‐GO/TiO2 nanocomposite as flexible films for solar cells and electrical energy storage applications.

Nanofiber-reinforced polymer nanocomposite with hierarchical interfaces for high-temperature dielectric energy storage applications

Flexible polymer nanocomposites reinforced by high-dielectric-constant ceramic nanofillers have shown great potential for dielectric energy storage applications in advanced electronic and electrical systems. However, it remains a challenge to improve their energy density and energy efficiency at high temperatures above 150°C. Here, we report a nanofiber-reinforced polyetherimide nanocomposite employing BN-BaTiO3 heterogeneous nanofibers as fillers, where the BN nanoparticles were embedded inside BaTiO3 nanofibers to create BN/BaTiO3/PEI hierarchical interfaces. The high dielectric constant and the geometric large aspect ratio of the BN-BaTiO3 heterogeneous nanofibers lead to simultaneously increased dielectric constant and breakdown strength of the nanocomposite over a broad temperature range. In particular, the emerging hierarchical BN/BaTiO3/PEI interfaces enable promoted density and energy level of traps for the mobile charges, which further suppresses the conduction loss and improves the breakdown strength under high temperatures, as confirmed by a combination of thermally stimulated depolarization current measurement and phase-field simulation. Finally, the nanocomposite with hierarchical interfaces boosts an ultrahigh energy density of 5.23 J cm−3 with an energy efficiency of > 90% at 150°C, which is the highest energy density reported so far in nanofiber-reinforced polymer nanocomposites and also outperforms most nanocomposites counterparts dispersed with nanoparticles and nanosheets. Our work demonstrates hierarchical interface engineering as an effective strategy to promote the high-temperature energy storage performance of fiber-reinforced polymer nanocomposites, which is of significance for their applications in high-temperature harsh conditions.

Three-Dimensional Printed Highly Porous and Flexible Conductive Polymer Nanocomposites with Dual-Scale Porosity and Piezoresistive Sensing Functions.

Highly flexible, deformable, and ultralightweight structures are required for advanced sensing applications, such as wearable electronics and soft robotics. This study demonstrates the three-dimensional (3D) printing of highly flexible, ultralightweight, and conductive polymer nanocomposites (CPNCs) with dual-scale porosity and piezoresistive sensing functions. Macroscale pores are established by designing structural printing patterns with adjustable infill densities, while the microscale pores are developed by phase separation of the deposited polymer ink solution. A conductive polydimethylsiloxane solution is prepared by mixing polymer/carbon nanotubes with non-solvent and solvent phases. Silica nanoparticles are utilized to modify the rheological properties of the ink, making direct ink writing (DIW) feasible. 3D geometries with various structural infill densities and polymer concentrations are deposited using DIW. The solvent is evaporated during a stepping heat treatment, leading to non-solvent droplet nucleation and growth. The microscale cellular network is developed by removing the droplets and curing the polymer. Up to 83% tunable porosity is achieved by independently controlling the macro- and microscale porosity. The effect of macroscale/microscale porosity and printing nozzle sizes on the mechanical and piezoresistive behavior of the CPNC structures is explored. The electrical and mechanical tests demonstrate a durable, extremely deformable, and sensitive piezoresistive response without sacrificing mechanical performance. The flexibility and sensitivity of the CPNC structure are enhanced up to 900 and 67% with the development of dual-scale porosity. The application of the developed porous CPNCs as piezoresistive sensors for detecting human motion is also evaluated.

Flexible metamaterial based microwave absorber with epoxy/graphene nanoplatelets composite as substrate

Customization of substrates for the design of metamaterial absorbers gives the user a wide choice of parameters like flexibility, thickness, dielectric constant, etc. Polymer composites are attractive in this regard as they provide a variety of options to fabricate substrates with desirable properties depending on the matrix and filler materials. In this work, flexible polymer nanocomposites with different weight percentages of graphene nanoplatelets (GnP) in epoxy were fabricated and the dielectric characterization was performed. The presence of GnP increased the real part of the dielectric constant from 2.5 for 0 wt. % to 14.7 for 9 wt. % of the epoxy-GnP composites measured in X-band frequency. The substrate with 5 wt. % of GnP in epoxy having a relative permittivity of 7.3–j0.25 is chosen to design a metamaterial absorber, and the absorption studies are carried out numerically. The proposed absorber having a thickness of λ/22 is shown to have a maximum absorption of 99.8% at the frequency 9.88 GHz. Furthermore, an equivalent circuit model of the absorber is proposed and the analytical values of the circuit elements are determined. The metamaterial prototype is fabricated by coating metallic resonating structures on top of the flexible E-GnP5 substrate of thickness 1.4 mm by thermal evaporation. The performance of the fabricated absorber agrees well with the simulation results. These polymer nanocomposites with good flexibility, thermal stability, and optimum dielectric properties would be the future materials for developing conformal metamaterial absorbers for microwave applications.

Flexible dielectric polymer nanocomposites with improved thermal energy management for energy-power applications

Most polymer materials are thermal and electrical insulators, which have wide potential in advanced energy-power applications including energy conversion. However, polymers get softened when in contact with heat, which causes their molecular chains to flow as the temperature increases. Although polymer dielectrics exhibit high power density, they face challenges of low energy density which is due to the low dielectric permittivity associated with them. Therefore, this study tried to address the poor thermal energy management and low energy density of poly (vinylidene fluoride) (PVDF) while maintaining its flexible property using low content of hybrid carbon nanotubes (CNTs–0.05wt%, 0.1wt%) and boron nitride (BN–5wt%, 10wt%) nano-reinforcements. The nanocomposites were developed through solvent mixing and hot compression processes. The dielectric constant increased from 9.1 for the pure PVDF to 42.8 with a low loss of about 0.1 at 100 Hz for PVDF-0.1wt%CNTs-10wt%BN. The thermal stability of the nanocomposites was enhanced by 55°C compared to the pure PVDF. The nanocomposites also showed improved melting and crystallization temperatures. The developed PVDF-CNTs-BN nanocomposites showed significant enhancements in thermal energy management, stability, and dielectric properties. The significantly improved properties are credited to the synergetic effects between CNTs and BN in the PVDF matrix in promoting homogeneous dispersion, thermal barrier, interfacial polarization/bonding, insulative and conductive properties. Therefore, the developed nanomaterials in this study can find advanced applications in the energy-power sector owing to their enhanced performances.

Flexible Graphite Nanoflake/Polydimethylsiloxane Nanocomposites with Promising Solar–Thermal Conversion Performance

Flexible polymer nanocomposites have emerged as promising photothermal materials for various solar energy applications. However, developing photothermal materials meeting low cost, excellent light absorption capability, and facile fabrication processes has remained challenging. Herein, a set of graphite nanoflake (GnF)/polydimethylsiloxane (PDMS) nanocomposites having different concentrations from 1 to 10 wt % GnF are fabricated to find the optimum amount of GnF in a GnF/PDMS nanocomposite for the maximum absorption of solar energy within the entire solar spectrum. The optical and photothermal properties of GnF/PDMS nanocomposite films were found to be optimum at 3 wt % GnF/PDMS. Specifically, the total solar absorption is 94.8 ± 0.20%, outperforming most of the previous flexible carbon-based polymer nanocomposites. As an example of the potential application of optimized GnF/PDMS nanocomposites, a floatable interfacial water evaporator was developed by dip-coating GnF/PDMS on polyurethane (PU) foam. The coated PU at 1 wt % GnF/PDMS yields an evaporation rate of 1.14 Kg/m2·h and solar–vapor conversion efficiency of 68.2% under 1 sun illumination. The advantages of stable coating of GnF/PDMS nanocomposites and their excellent photothermal effect will benefit various solar-powered applications such as desalination, purification, and steam generation.

Fabrication of Low Electrical Percolation Threshold Multi-Walled Carbon Nanotube Sensors Using Magnetic Patterning

Soft robotics is an expanding area with multiple applications; however, building low-cost, soft, and flexible robots requires the development of sensors that can be directly integrated into the soft robotics fabrication process. Thus, the motivation for this work was the design of a low-cost fabrication process of flexible sensors that can detect touch and deformation. The fabrication process proposed uses a flexible polymer nanocomposite with permanent magnets strategically placed where the conductive electrodes should be. The nanocomposite is based on poly(dimethylsiloxane) (PDMS) and multi-walled carbon nanotubes (MWCNTs). The MWCNT contains ferromagnetic impurities remaining from the synthesis process, which can be used for magnetic manipulation. Several electrode geometries were successfully simulated and tested. The magnetic patterning was simulated, allowing the fabrication of conductive patterns within the composite. This fabrication process allowed the reduction of the electrical resistivity of the nanocomposites as compared to the composites with homogeneous MWCNT dispersion. It also allowed the fabrication of piezoresistive and triboelectric sensors at MWCNT concentration as low as 0.5 wt.%. The fabrication process proposed is flexible, allows the development of sensors for soft robotics, as well as monitoring large and unconventional areas, and may be adapted to different mould shapes and polymers at low cost.

Enhanced energy harvesting performances of flexible piezoelectric nanocomposite based on CNTs@PZT nanofibers network

Flexible organic/inorganic piezoelectric nanocomposites are highly demanded for flexible wearable electronic devices due to their excellent mechanical flexibility and high piezoelectric performance. However, the output performance of ceramic-polymer-based piezoelectric nanogenerators (PENGs) is restricted by the poor electrical conductivity of the organic matrix and the distinct discrepancy in mechanical strength between inorganic filler and organic matrix. Herein, we propose a flexible piezoelectric polymer nanocomposite based on CNTs@PZT nanofibers (NFs) network where the carbon nanotubes (CNTs) were introduced into the piezoelectric lead zirconate titanate (PZT) NFs to simultaneously improve the electrical conductivity and mechanical strength of nanocomposites. When subjected to a periodical bending deformation, the CNTs@PZT NFs network-based PENG with optimal addition of CNTs (0.6 wt%) generates a maximum electrical output up to ∼12.5 V and ∼80 nA cm−2 which is four times higher than that of PENGs without CNTs doping. An ultrahigh power density of 91.7 nW cm−2 is obtained with an external load resistance of 40 MΩ when pressed via a 10 N compressive force, and furthermore, the generated power could charge a capacitor and further light a commercial LED. This work may pave a new way for the development of high-output nanocomposite-type PENGs.

Liquid crystal-assisted manufacturing of flexible holographic polymer nanocomposites for high-security level anticounterfeiting

Flexible manufacturing of holographic polymer nanocomposites has been realized by the synergy of hydrogen bonding networks with thiol–ene click reaction, which allows for the reconstruction of polarization-sensitive 3D images for advanced security.

Core-shell Structured Ag@PDA Nanowires and BT@PDA Nanoparticles for Three-phase Flexible Polymer Nanocomposites with Excellent Dielectric Properties

In this work, core-shell structured polydopamine coated silver nanowires (Ag@PDA NWs) and polydopamine coated BaTiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> nanoparticles (BT@PDA NPs) are accurately prepared. Through embedding Ag@PDA NWs and BT@PDA NPs into the P(VDF-HFP) matrix, flexible nanocomposites with high dielectric constant and low dielectric loss are prepared by constructing three-phase structure. The crystal structure, thermal properties and dielectric properties of the nanocomposites are fully investigated. Compared with two-phase nanocomposites, which are composed by Ag@PDA NWs and P(VDF-HFP), the dielectric constant of the three-phase nanocomposites is improved from 28.1 to 67.9. Additionally, owing to the presence of the polydopamine shell, the nanofillers are homogeneously dispersed and the interfacial adhesion between the nanofillers and polymer matrix is also enhanced, leading to the dielectric loss and electric conductivity of three-phase nanocomposites remain relatively low level. Furthermore, the dielectric properties of the three-phase nanocomposites exhibit weak temperature dependence.

Flexible electronics from hybrid nanocomposites and their application as piezoresistive strain sensors

Poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) is one of the most commonly used styrene-based thermoplastic elastomer (TPE) with unique properties including high resilience and stretchability. In the case of incorporation of conductive fillers into SEBS matrix piezoresistive strain sensors can be fabricated. In this study, conductive flexible polymer nanocomposites were prepared by combination of solvent casting and compression molding by using SEBS matrix with conductive fillers including carbon black (CB), vapor grown carbon nanofibers (VGCNFs), and their mixtures (CB:VGCNF, 1:1) at various filler loadings from 0.5 to 6.5 wt%. Two different SEBS with different block ratios (styrene to ethylene-butylene ratio (S/EB): 13/87 and 19/81) were used in order to observe their effects on morphological, mechanical, thermal, electrical, and electromechanical properties. In all cases, single and hybrid fillers were found to show good dispersion in the matrix. However, polymer type was found significant in terms of mechanical, electrical, and electromechanical properties. SEBS with lower EB content (S/EB:19/81) led to formation of conductive network at lower concentrations for fillers. Although both polymers and all fillers can be used for strain sensors, hybrid composites generally tend to show higher sensitivity. The strain-reversibility of the composites was directly affected by filler type, filler ratio, and polymer type. The most sensitive and stable response was obtained from 3.5 wt% CB-VGCNF filled SEBS with S/EB:19/81 block type. Test conditions (strain %, test speed) were found significant for both mechanical and electromechanical properties. Generally, for both polymers, lower filler ratio, higher strain ratio, and lower test speed resulted in higher sensitivity. • The polymer nanocomposites were prepared by combination of high shear mixing, solvent casting, and compression molding. • CB, VGCNF and CB-VGCNF mixtures and two different SEBS polymers (S/EB: 13/87 and 19/81) were used. • 3.5 wt% CB-VGCNF/SEBS (S/EB:19/81) showed the most sensitive and stable response and GF was between 333-113. • Filler type, filler ratio, polymer type, strain amplitude, and test speed were significant for piezoresistance