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Radiative cooling is promising in meeting the current global demand for green sustainable development. However, the effective cooling of the existing radiant cooler will be limited due to the serious solar energy absorption and poor thermal insulation performance on the cold side. To addresss these issues, we propose herein a novel composite material of silicon dioxide (SiO 2) aerogel microspheres combined with polyvinylidene fluoride-cohexafluoropropylene (PVDF-HFP) nanofiber membrane, in which SiO 2 aerogel microspheres are firstly synthesized by sol-gel method and then incorporated into PVDF-HFP nanofiber membrane to give radiative cooling performance. As we expected, the molecular vibration characteristics of PVDF-HFP nanofiber membrane and the phonon polarization resonance of Si-O-Si bond in the transparent window can enhance the infrared emissivity of the membrane surface. In addition, the high porosity and the mesoporous structure formed by the interconnection of nano-network skeletons of SiO 2 aerogel microspheres determine its excellent thermal insulation performance. The as-prepared material displays that the average solar reflectance of the composite membrane is 96.07 % and the average infrared emissivity of the atmospheric window is 94.95 %. Notably, when the average solar radiation intensity is 885.56 W•m−2, the passive radiative cooling temperature during the day can reach 11.2 °C. Furthermore, this material has excellent self-cleaning and thermal insulation performance, making it a potential radiant cooling candidate in many fields. [ABSTRACT FROM AUTHOR]

Barium titanate doped with calcium and zirconium (BCZT) relaxor ferroelectric ceramics enhance energy storage capabilities due to their excellent ferroelectric and dielectric properties. In this investigation, BCZT particles (Ps) were incorporated into poly (vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) using the solvent casting method to prepare biocompatible composite films with varying BCZT Ps contents. The uniform dispersion and distribution of BCZT Ps throughout the polymer matrix results in robust interfacial interactions, promoting improved nucleation of the β-phase in PVDF-HFP and increased thermal stability with higher BCZT Ps loading. The Young's modulus and tensile strength of the composites experienced respective increases of 78.2 % and 41.8 % with the addition of 20 wt% BCZT Ps. While the dielectric constant was improved from 12 to 31. This research contributes to the development of flexible composite films with different BCZT Ps contents, to promote an innovative and environmentally friendly energy harvesting technology. This innovation captures environmental vibrations and converts them into electrical energy to supply a variety of sensors. [ABSTRACT FROM AUTHOR]

An innovative approach has been adopted through the synthesis of a cost‐effective ferroelectric host polymer, which was integrated with Barium Titanate (BaTiO3) to develop an efficient electrospun Polyvinylidene Fluoride‐Hexafluoropropylene/BaTiO3 (PVdF‐HFP/BaTiO3) nanocomposite (PBT), designated for energy harvesting and piezocatalytic applications. FT‐IR affirmed the existence of the crystalline β‐phase within the nanofibers. SEM images showed that nanofiber diameter decreases as applied voltage is increased in electrospinning. The BaTiO3 nanoparticles were scattered evenly in PBT, but at lower voltages, they aggregate. PBT showed enhanced piezoelectric performance under higher voltage conditions, registering a maximum piezoelectric output of ~7.7 V and an output current of 0.77 μA. Moreover, the composite exhibited a power density of 14.15 mW/m2 at a load resistance of 20 MΩ. Fabricated piezoelectric nanogenerator (PENG) demonstrated practical utility in flexible electronics, notably in charging capacitors of 0.47 μF and 1 μF. Additionally, the piezocatalytic degradation of the antibiotic ciprofloxacin (CIP) was effectively achieved using the electrospun nanofibers, with an impressive degradation rate of up to 99.6 % within 30 minutes under acidic conditions, and the material displayed notable reusability, maintaining up to 95.5 % efficiency after five cycles. DFT calculations and COMSOL simulations alongside a comparative examination of the electronic properties of PBT. [ABSTRACT FROM AUTHOR]

Energy storage devices play a crucial role in all kinds of electronic devices. Rechargeable lithium-ion batteries have run across problems such as energy density, toughness, and safety. In order to conquer these hindrances, in this work, a novel solid-state polymer electrolyte for lithium-ion batteries was synthesized by blending polymethyl methacrylate (PMMA) in poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with constant weight percent of ethylene carbonate (EC) and lithium bis (trifluoro methane sulfonyl) imide (LiTFSI), and different concentrations of calcium oxide (CaO). The composite polymer electrolytes (CPEs) (PVdF-HFP:PMMA:LiTFSI:EC:CaO) were fabricated using the solution casting technique. Powder XRD reveals enhancement in intensity with increasing CaO content. FTIR shows the interaction between the polymer-salt matrix. Among the analyzed films, PVdF-HFP:PMMA:LiTFSI:EC:CaO (10 wt.%) exhibits high ionic conductivity (10–4 S/cm) and good electrochemical (4 V) and thermal stability (350℃) which makes it suitable for solid-state electrolyte as a separator in energy storage applications. [ABSTRACT FROM AUTHOR]

This work focuses on the development of a composite polymer electrolyte (CPE) for all‐solid‐state lithium metal batteries (ASSLMBs), integrating LLTO nanofibers into a PEO (polyethylene oxide)‐PVDF‐HFP (poly(vinylidene fluoride‐cohexafluoropropylene)) matrix with LiClO4 as the lithium salt. The PEO has high ionic conductivity and flexibility, and the PVDF‐HFP has high mechanical strength and electrochemical stability. Therefore, the resulting composite has improved electrochemical performance and mechanical properties. Incorporating LLTO nanofibers enhances ionic conductivity due to the one‐dimensional ion transport pathways provided by the nanofibers while maintaining mechanical integrity and air stability, overcoming the challenges associated with conventional fillers. The prepared CPE demonstrates exceptional electrochemical stability up to 5.1 V versus Li/Li+, making it suitable for high‐voltage applications over traditional polymer electrolytes. The optimized CPE with 15 wt% LLTO provides the ionic conductivity of 1.1 × 10−5 S cm−1 at room temperature and reaches 1.46 × 10−4 S cm−1 at 80°C. The assembled LiNi1/3Mn1/3Co1/3PO4||PEO‐PVDF‐HFP‐LiClO₄‐LLTO||Li based 2032 coin cell worked in between 3 and 4.8 V versus Li/Li+ potential window without any electrolyte decomposition from 0.5 to 5 mV/s scan rates. Similarly, the fabricated LiFePO₄||PEO‐PVDF‐HFP (1:2)‐LiClO4‐LLTO (15 wt%)||Li cell provides an initial capacity of 149 mAh g−1 at 0.1 C and 85 mAh g−1 at 0.5 C, exploring its potential for lithium metal batteries. Overall, this work offers a promising pathway for developing advanced solid polymer electrolytes for next‐generation lithium metal batteries, which combine high ionic conductivity, excellent electrochemical performances, and robust mechanical properties. [ABSTRACT FROM AUTHOR]

A salient bottleneck to driving the wider use of polyvinylidene fluoride (PVDF) and its copolymers in smart applications is the requirement for a high-voltage poling process required to activate their $\beta $β-phase crystal structure before the realisation of the piezoelectricity response. In pursuit of enhancing the β-phase content of PVDF-based films, various approaches have been employed in recent years. Yet, a perfect solution to the challenge remains elusive. Here, we report a preliminary investigation into the production of unpoled poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) films reinforced with barium titanate (BaTiO3) and activated carbon (AC) to improve the piezoelectric property. Employing the mixture design of experiments (MDOE) method, various formulations of the composite’s constituents weight fractions were determined. Afterwards, series of composite films were produced via a toxic-free solution casting method and characterised by Fourier Transform Infrared Spectrum (FTIR) to determine the β-phase content. A non-linear polynomial regression model was established from the experimental FTIR data, and the adequacy of the model was confirmed using ANOVA. Subsequently, an MDOE-enabled optimisation was undertaken, generating a formulation of the composite to obtain the highest β-phase content to be $15$15 wt.% BaTiO3 and $0.74$0.74 wt.% AC. This combination produces a theoretically predicted β-phase content of $72.7$72.7%. A further experimental test employing the optimal formulation produced a β-phase content of $71.90$71.90%, achieved with neither mechanical stretching, thermal annealing, nor electrical poling. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional supramolecular polymer (MSP) cross-linked with the PVDF-HFP gel electrolyte. • The composite gel electrolyte (PH-10%MSP-GE) shows enhanced hardness and ionic conductivity. • The PH-10%MSP-GE demonstrates good interfacial adaptability with Li metal electrodes. • The Li|PH-10%MSP-GE|LiFePO 4 cell exhibits excellent electrochemical performance. Lithium (Li) metal batteries have the advantage of high energy density, but the Li dendrites risk piercing the separator and causing a short circuit in the battery. Replacing the liquid electrolytes with gel electrolytes is considered an effective strategy to solve the issues. Herein, a poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP)-based gel electrolyte, improved with multifunctional supramolecular polymer (MSP), was prepared to enhance the cycling stability and energy density of quasi-solid-state Li metal batteries. The MSP addictive constructs a cross-linked network structure with PVDF-HFP matrix and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) through hydrogen bonding, improving the mechanical strength of the composite gel electrolyte (PH-10%MSP-GE) to against the growth of Li dendrites. Moreover, the pre-lithiated sulfonic acid groups, conductive polyether groups of MSP, and the attraction of TFSI– anions, promote the Li-ion transportation of the composite gel electrolyte. Finally, the Li||Li symmetric cell cycle stably for over 450 h. The Li||LiFePO 4 full cell demonstrates a high energy density and excellent cycling stability for over 600 cycles, with a capacity retention rate of up to 98.7%. This work provides valuable insights into the preparation of multifunctional composite gel polymer electrolytes and competitive quasi-solid-state Li metal batteries. [ABSTRACT FROM AUTHOR]

A simple solution casting technique was used to formulate films of polyvinylidenefluoride‐co‐hexafluoropropylene, polymethylmethacrylate, and Ti3AlC2 MAX phase polymer nanocomposites (PPT) with different filler content. The functional groups present in the PPT films were studied using the Fourier transform infrared spectroscopy and the nature of crystallinity was observed using X‐ray diffraction technique. The morphology of the films was studied by scanning electron microscopy. The thermal analysis was done using the thermogravimetric analysis and differential thermogravimetry analysis. The tensile behavior of the prepared films was studied from the stress‐strain graphs. The ultraviolet–visible spectra revealed their optical characteristics. The dielectric parameters of the polymer blend and nanocomposite films like dielectric constant, loss tangent, AC conductivity, and complex impedance spectroscopy with corresponding equivalent circuits were studied. A comparative study of the above parameters was done for both the polymer blend and nanocomposites to find out the advancement in the properties of the prepared nanocomposite compared with the polymer blend. The nanocomposite film having 3 wt% of Ti3AlC2 MAX phase filler loading exhibited the best properties among all the nanocomposites. The enhanced dielectric properties of the nanocomposites with mechanical and thermal resistance can be used for real‐time efficient energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ternary composite membranes have been developed for battery separator applications. • Membranes have been developed by varying silver nanowires and titanium dioxide nanoparticle content. • Ternary composites show improved mechanical and electrochemical responses. • An ionic conductivity > 10−4 S/cm has been obtained independently of the filler type and content. • The highest discharge capacity value has been obtained for the 5 wt% AgNWs/5 wt% TiO 2 /PVDF-HFP membranes. In the realm of polymer composites, there is growing interest in the use of more than one filler for achieving multifunctional properties. In this work, a composite separator membrane has been developed for lithium-ion battery application, by incorporating conductive silver nanowires (AgNWs) and titanium dioxide (TiO 2) nanoparticles into a poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) polymer matrix. The composite membranes were manufactured by solvent casting and thermally induced phase separation, with total filler content varying up to 10 wt%. The ternary composites composites present improved mechanical characteristics, ionic conductivity and lithium transfer number compared to the neat polymer matrix. On the other hand, the filler type and content within the composite has little bearing on the morphology, polymer phase, or thermal stability. Once applied as a separator in lithium-ion batteries, the highest discharge capacity value was obtained for the 5 wt% AgNWs/5 wt% TiO 2 /PVDF-HFP membrane at different C-rates, benefiting from the synergetic effect from both fillers. This work demonstrates that higher battery performance can be achieved for next-generation lithium-ion batteries by using separator membranes based on ternary composites. [ABSTRACT FROM AUTHOR]

Membrane wetting caused by substances in the feed solution with low surface tension has posed serious issues for membrane distillation (MD). Omniphobic membranes could be helpful when dealing with this problem because they strongly repel liquids with a wide range of surface tensions. We fabricated electrospun omniphobic membranes containing PVDF‐TEOS‐PFDTMS, PVDF‐HFP‐TMOS‐PFDTMS, and PVDF‐HFP‐TEOS‐PFDTMS. All electrospun membranes have shown contact angles >90°, but the electrospun membrane containing PVDF‐HFP‐TEOS‐PFDTMS has shown super repellence with a contact angle >150° and maintains stable salt rejection and water flux in direct contact MD processes in the presence of sodium dodecyl sulfate surfactant (up to 0.3 mM). Furthermore, the morphology and crystallinity of the electrospun membranes were studied by scanning electron microscopy and Fourier‐transform infrared spectroscopy, and the percentage composition of elements was analyzed by x‐ray photoelectron spectroscopy. liquid entry pressure, mechanical strength, and the porosity of the electrospun omniphobic membranes were also studied. [ABSTRACT FROM AUTHOR]

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules' immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel's properties, and QsDSSCs' performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications. [ABSTRACT FROM AUTHOR]

Highlights Flexible sensors, made of PVDF‐HFP reinforced with carbon nanotubes (CNTs), are manufactured by solvent casting. More specifically, the effect of evaporation temperature and sonication time is explored. It is seen that two effects govern the dispersion of CNT: the sedimentation half‐time, and the breakage induced by the ultrasonication process. In this regard, it is found that 60°C is an optimum evaporation temperature to reach the highest value of electrical conductivity, since it offers a good balance between these effects, leading to the creation of a more efficient electrical network. This is also confirmed by the AC analysis, where these samples show the highest characteristic frequencies. The electromechanical results show a greater dependency on evaporation temperature for low sonication times, as the breakage induced by an ultrasonic process is not so pronounced and, therefore, the sedimentation effect plays a more dominant role. In addition, cycling tests show robust electromechanical response with cycling, and creep tests prove good electrical response of the sensors, less than 200 ms in some cases. Finally, proof of concept testing of wrist, shoulder, and neck monitoring highlights the potential of the proposed materials for sensing applications. PVDF‐HFP/CNT nanocomposite strain sensors via solvent casting are proposed. The effect of evaporation temperature and sonication time is studied. DC and AC conductivities were analyzed and modeled via an equivalent circuit. An outstanding Gauge Factor of 86.30 × 104 is achieved at 95% of strain level. Two proof‐of‐concepts of medium and large movements are successfully achieved. [ABSTRACT FROM AUTHOR]

Fouling and biofouling remain significant challenges in seawater desalination plants. One practical approach to address these issues is to develop anti-biofouling membranes. Therefore, novel hybrid zinc phthalocyanine/polyvinylidene fluoride-co-hexafluoropropylene (Zn(4-PPOx)4Pc/PVDF-HFP) membranes were prepared by electrospinning to evaluate their properties against biofouling. The hybrid nanofiber membrane was characterized by atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and contact angle measurements. The theoretical calculations of PVDF-HFP, Zn(4-PPOx)4Pc), and Zn(4-PPOx)4Pc/PVDF-HFP nanofibers were performed using a hybrid functional RB3LYP and the 6-31 G (d,p) basis set, employing Gaussian 09. DFT calculations illustrated that the calculated physical and electronic parameters ensured the feasibility of the interaction of PVDF-HFP with Zn(4-PPOx)4Pc via a halogen–hydrogen bond, resulting in a highly stable and remarkably reactive structure. Moreover, molecular electrostatic potential (MEP) maps were drawn to identify the reactive regions of the Zn(4-PPOx)4Pc and PVDF-HFP/Zn(4-PPOx)4Pc nanofibers. Molecular docking analysis revealed that Zn(4-PPOx)4Pc has highest binding affinity (−8.56 kcal/mol) with protein from S. aureus (1N67) mainly with ten amino acids (ASP405, LYS374, GLU446, ASN406, ALA441, TYR372, LYS371, TYR448, LYS374, and ALA442). These findings highlight the promising potential of Zn(4-PPOx) 4Pc/PVDF-HFP nanocomposite membranes in improving the efficiency of water desalination by reducing biofouling and providing antibacterial properties. [ABSTRACT FROM AUTHOR]

In today's technological landscape, advancing methods for producing conductive membranes that simplify and streamline the development of advanced interface materials is crucial. This study introduces a versatile and innovative method for fabricating superhydrophilic, conductive nanofibrous membranes based on the in situ synthesis of polypyrrole nanoparticles on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) electrospun fibers. The composite membranes morphologically exhibit a particle‐decorated nanofibrous configuration, with polypyrrole nanoparticles distributed along the individual fibers' surface. The nanoparticle‐nanofiber configuration shows distinctive properties; electrochemically, the electrospun mats demonstrate excellent inherent electrical conductivity, good cyclic and high electrochemical stability, and low resistance. Furthermore, the amphiphilic and superhydrophilic behavior, achieved through nanotopography, porosity and interactions between the intrinsically conductive polymer and the PVDF‐HFP fibers, enables efficient uptake of polar and nonpolar analytes. The membranes also demonstrate good in vitro cell viability of both murine and human fibroblasts. Given its efficient interaction with liquids and omnidirectional 360‐degree conductivity, this material emerges as an excellent candidate for use as a biocompatible, multifunctional interface layer. The produced nanoparticle‐nanofibrous membrane materials offer a promising platform for interface applications, featuring enhanced spatiotemporal configurations and wide‐ranging applicability. [ABSTRACT FROM AUTHOR]

Cellulose has advantages of easy availability, low price, renewability and biodegradability, making it a very promising substitute for fossil-based materials. A safe composite cellulose membrane for quasi-solid-state lithium ion batteries has been developed by coating cellulose separators with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and lithium aluminum titanium phosphate (LATP). This membrane exhibits excellent electrochemical performance, with an ionic conductivity as high as 2.1 mS cm−1, and a lithium-ion transference number of 0.57. The membrane shows good electrolyte wetting properties, with porosity and liquid electrolyte uptake of 47.2 % and 401.7 %, respectively. It has good thermal stability and can maintain its dimensional stability even at 200 ℃. The capacity retention of the quasi-solid-state LiFePO4/Li battery assembled with this membrane after 200 cycles at 0.2 C is about 86.7 %. The quasi-solid-state battery has good thermal stability and is not prone to thermal runaway.

Abstract This study is the first application of a PVDF-HFP-based polymer inclusion membrane incorporating the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as the base polymer and extractant for the extraction of bismuth(III), respectively. It is demonstrated that the PIM comprised of 60 wt% PVDF-HFP and 40 wt% D2EHPA is the most effective in the extraction of bismuth(III) from feed solution containing 20 mg L−1 bismuth(III) and 0.2 mol L−1 sulfate adjusted to pH 1.4. The extracted bismuth(III) ions are back-extracted quantitatively to the receiving solution containing 1 mol L−1 sulfuric acid. The stoichiometry experiments reveal that the Bi: D2EHPA ratio in the bismuth(III) extracted complex is 1:6, and D2EHPA is dimer. Moreover, it is shown that the studied PIM has high selectivity in the extraction of bismuth(III) over other interfering ions such as Mo(VI), Cr(III), Al(III), Fe(III), Ni(II), Zn(II), Cd(II), Co(II), Cu(II), and Mn(II). The interference of Fe(III) is also eliminated by masking with fluoride, leading finally to a nearly pure extraction of bismuth(III).

High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and ferromagnetic cobalt ferrite (CoFe2O4) (0.00 ​wt% to 0.2 ​wt%) are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling. The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments. For pure PVDF-HFP films, when the maximum electric field Emax is 120 ​MV/m, the calibrated open circuit voltage reaches 2.93 ​V, which is much higher than those poled at lower electric fields (70 ​MV/m: 1.41 ​V; 90 ​MV/m: 2.11 ​V). Furthermore, the addition of CoFe2O4 also influences the piezoelectricity dramatically. In the samples containing 0.15 ​wt% CoFe2O4, the calibrated open circuit voltage increases to the maximum value of 3.57 ​V. Meanwhile, the relative fraction of the β-phase and the crystallinity degree are 99% and 48%, respectively. The effects of CoFe2O4 nanoparticles on initial crystallization, uniaxial stretching and high electric field poling are investigated by XRD, FTIR and DSC.

This study is the first application of a PVDF-HFP-based polymer inclusion membrane incorporating the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as the base polymer and extractant for the extraction of bismuth(III), respectively. It is demonstrated that the PIM comprised of 60 wt% PVDF-HFP and 40 wt% D2EHPA is the most effective in the extraction of bismuth(III) from feed solution containing 20 mg L−1 bismuth(III) and 0.2 mol L−1 sulfate adjusted to pH 1.4. The extracted bismuth(III) ions are back-extracted quantitatively to the receiving solution containing 1 mol L−1 sulfuric acid. The stoichiometry experiments reveal that the Bi: D2EHPA ratio in the bismuth(III) extracted complex is 1:6, and D2EHPA is dimer. Moreover, it is shown that the studied PIM has high selectivity in the extraction of bismuth(III) over other interfering ions such as Mo(VI), Cr(III), Al(III), Fe(III), Ni(II), Zn(II), Cd(II), Co(II), Cu(II), and Mn(II). The interference of Fe(III) is also eliminated by masking with fluoride, leading finally to a nearly pure extraction of bismuth(III). [ABSTRACT FROM AUTHOR]

For enhanced security in hardware‐based security devices, it is essential to extract various independent characteristics from a single device to generate multiple keys based on specific values. Additionally, the secure destruction of authentication information is crucial for the integrity of the data. Doped amorphous indium gallium zinc oxide (a‐IGZO) thin‐film transistors (TFTs) using poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) induce a dipole doping effect through a phase‐transition process, creating physically unclonable function (PUF) devices for secure user information protection. The PUF security key, generated at VGS = 20 V in a 20 × 10 grid, demonstrates uniformity of 42% and inter‐Hamming distance (inter‐HD) of 49.79% in the β‐phase of PVDF‐HFP. However, in the γ‐phase, the uniformity drops to 22.5%, and inter‐HD decreases to 35.74%, indicating potential security key destruction during the phase transition. To enhance security, a multi‐factor authentication (MFA) system is integrated, utilizing five security keys extracted from various TFT parameters. The security keys from turn‐on voltage (VON), VGS = 20 V, VGS = 30 V, mobility, and threshold voltage (Vth) exhibit near‐ideal uniformities and inter‐HDs, with the highest values of 58% and 51.68%, respectively. The dual security system, combining phase transition and MFA, establishes a robust protection mechanism for privacy‐sensitive user information. [ABSTRACT FROM AUTHOR]

With the escalating issue of air pollution, the development of air filtration materials that can efficiently remove particulate pollutants, particularly nanosized particles, from air has attracted more and more research attention in recent years. Electrospun nanofiber membranes with a nanoscale pore structure have been widely used as air filtration materials. Along these lines, in this work, polyvinylidene fluoride-co-hexafluoropropyle (PVDF-HFP) nanofiber membranes with a multihierarchical gradient structure were fabricated by varying the sodium dodecyl sulfate (SDS) concentration. The proposed multihierarchical gradient structure was composed of upper, middle, and lower nanofiber layers, which could effectively filter PM0.3. The decreased nanofiber diameter by increasing the SDS concentration was attributed to the low surface tension and high charge balance. Compared with the single- and double-hierarchical PVDF-HFP nanofiber membranes, the triple-hierarchical PVDF-HFP nanofiber membranes demonstrated excellent air filtration performance. Among them, F014 yielded optimal air filtration performance, exhibiting a high filtration efficiency of 99.50%, a low pressure drop of 71.4 Pa, and a quality factor of 0.0878 Pa–1. Furthermore, the filtration efficiency was maintained above 99% and the pressure drop just increased by 27.4% over a 40 min air filtration test, which indicated that F014 showcased exceptional durability, owing to the multihierarchical gradient structure. Our work paves the way for the fabrication of electrospun nanofiber membranes with a multihierarchical gradient structure using a straightforward method, highlighting their potential as an alternative to traditional air filter materials for various practical applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, a high‐performance composite nanofiber membrane with excellent air filtration and dye degradation properties was prepared by incorporating MIL‐53(Fe) nanoparticles into the electrospinning solution. The results showed that the filtration efficiency for PM2.5 of the PP/PVDF‐HFP/MIL‐53(Fe) composite nanofiber membrane reached up to 99.3% with the addition of 2 wt% MIL‐53(Fe). Moreover, the composite nanofiber membrane exhibited steady filtration efficiency across different parameters, including air velocity, PM2.5 concentration, and extended testing time. Furthermore, the incorporation of MIL‐53(Fe) significantly enhanced the removal efficiency of the composite nanofiber membrane toward Rh B, resulting in a remarkable 91% removal rate. The polymer/MOF composite nanofiber membranes prepared by simple and cheap electrospinning technology have a wide range of practical applications in the field of environmental protection. Highlights: PPM composite nanofiber membrane was prepared via electrospinning method.MIL‐53(Fe) nanoparticles were introduced to PPM composite nanofiber membrane.PPM composite nanofiber membrane showed excellent removal efficiency for PM2.5.PPM composite nanofiber showed a good removal performance for RhB in solution. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) is a standard electrolyte membrane and binder material for lithium‐ion batteries (LIBs) because of the benefits of membrane formation and strong mechanical properties. Still, its use is limited due to unavoidable defects such as high crystallinity and poor electrochemical performance. In this paper, a larger specific surface area and three‐dimensional (3D) permeable lamellae carboxylated g‐C3N4 (HCN) were successfully prepared by HNO3 and introduced into the PVDF‐HFP to obtain a high‐performance composite separator. The wettability and electrolyte absorption of PVDF‐HFP separator can be improved through the carboxylated HCN. More crucially, because PVDF‐HFP has several active sites and low crystallinity, adding HCN can greatly increase the ionic conductivity of separators. The ionic conductivity of PH‐HCN at 25 °C is 0.52 S cm−1, 4.7 times higher than the initial PVDF‐HFP membrane, and the oxidation potential can reach 4.8 V. The assembled lithium‐ion batteries half‐cell has a capacity of 71 % at a 5 C rate and 94 % after 400 cycles at a 2 C rate. Therefore, the improved separator has the potential to be applied to high‐performance LIBs. [ABSTRACT FROM AUTHOR]

Abstract In today's technological landscape, advancing methods for producing conductive membranes that simplify and streamline the development of advanced interface materials is crucial. This study introduces a versatile and innovative method for fabricating superhydrophilic, conductive nanofibrous membranes based on the in situ synthesis of polypyrrole nanoparticles on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) electrospun fibers. The composite membranes morphologically exhibit a particle‐decorated nanofibrous configuration, with polypyrrole nanoparticles distributed along the individual fibers' surface. The nanoparticle‐nanofiber configuration shows distinctive properties; electrochemically, the electrospun mats demonstrate excellent inherent electrical conductivity, good cyclic and high electrochemical stability, and low resistance. Furthermore, the amphiphilic and superhydrophilic behavior, achieved through nanotopography, porosity and interactions between the intrinsically conductive polymer and the PVDF‐HFP fibers, enables efficient uptake of polar and nonpolar analytes. The membranes also demonstrate good in vitro cell viability of both murine and human fibroblasts. Given its efficient interaction with liquids and omnidirectional 360‐degree conductivity, this material emerges as an excellent candidate for use as a biocompatible, multifunctional interface layer. The produced nanoparticle‐nanofibrous membrane materials offer a promising platform for interface applications, featuring enhanced spatiotemporal configurations and wide‐ranging applicability.

Supercapacitors based on ionic liquid gel polymer electrolytes (GPEs) have attracted considerable attention as a new energy storage device due to their good specific capacitance, good cycling capacity and stability. In this work, flexible gel polymer electrolyte (GPE) films were prepared and applied using three butyl imidazole ionic liquids with different anions as additives based on polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The structure and the mechanical properties of the GPE films and the electrical properties of the assembled symmetrical supercapacitors have been characterized. In particular, the structure–activity relationship between the structure and properties of the gel electrolyte was revealed by combining calculations with experiments. In particular, the structure–activity relationship between the structure and properties of the GPE was revealed through the combination of calculation and experiment. The results show that the electronegativity of the anions plays an important role in improving the stability and electrochemical properties of the gel system. This work is useful to further verify the influence of the anionic component of ionic liquids on the physical and chemical properties of gel electrolytes and to prepare more excellent solid electrolytes for supercapacitors. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte (SPE) films based on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF–HFP) with salt and ionic‐liquid (IL) are synthesized using the solution‐cast technique and summarized in this review. Doping ILs or salts increases ionic conductivity up to the device level. This is further confirmed using differential scanning calorimetry (DSC) and X‐ray diffraction (XRD) measurements. Polarized optical microscopy (POM) affirms that enhancement in ionic conductivity is due to increase in amorphous nature of film. The complex nature of polymer electrolyte films is confirmed using Fourier transform infrared (FT‐IR) spectroscopy. Overall results show that doping IL into polyether matrix is advantageous material playing a dominant role in electrochemical devices. [ABSTRACT FROM AUTHOR]

In this work, poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP)/mesoporous graphitic carbon nitride (mpg‐C3N4) composite fiber web have been prepared and characterized for photocatalytic methylene blue (MB) degradation and sensing applications. The electrospinning technique, operating at a flow rate of 1 mL/h and a voltage of 15 kV, was utilized to prepare the composite membranes of PVDF‐HFP with the uniform distribution of the mpg‐C3N4. The composite web demonstrated outstanding photocatalytic activity for the degradation of MB, reaching a quick 68% drop in MB concentration in just 45 min. The composite web furthermore worked as a sensor for MB detection. After MB exposure, the film resistance was increased, suggesting its potential as a chemiresistive sensor. The maximum resistivity of PVDF‐HFP/mpg‐C3N4 composites was found to be 90 Ω·m at 2% concentration of MB. The MB molecules' adsorption on the surface of the composite web and the existence of photocatalytic byproducts on the surface may be responsible for this shift in resistance. This dual functionality highlights the adaptability and potential of the PVDF‐HFP/mpg‐C3N4 composite web as a versatile material for environmental sensing and cleanup. This research presents a comprehensive approach to the synthesis, characterization, and evaluation of such flexible membranes for potential applications as self‐cleaning devices and chemiresistive sensor. Highlights: PVDF‐HFP/mpg‐C3N4 composite membranes act as an efficient material for MB degradation (68%) with visible light exposure.mpg‐C3N4 plays the role of active material in degradation.PVDF‐HFP/mpg‐C3N4 composite membrane also act as sensors for MB detection.Composite membrane becomes chemiresistive due to notable resistivity changes with MB concentration. [ABSTRACT FROM AUTHOR]

In this work, zirconia (ZrO2) nanoparticles (NPs) incorporated poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanocomposites were fabricated at varying weight ratios through solution casting approach. The structural properties of PVDF-HFP/ZrO2 nanocomposites have been investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The strong interaction of ZrO2 with the PVDF-HFP matrix was observed revealing the structural modifications in the nanocomposites. The thermal degradation behavior of PVDF-HFP/ZrO2 nanocomposites was investigated by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Addition of ZrO2 in the PVDF-HFP matrix has greatly improved the thermal stability of the PVDF-HFP/ZrO2 nanocomposites. The dielectric properties of the PVDF-HFP/ZrO2 nanocomposites were investigated as a function of frequency and temperature. The dielectric constant was observed to be higher at low frequency and decreased abruptly on increasing the frequency. Moreover, the impedance behavior of PVDF-HFP/ZrO2 nanocomposites with different loadings was studied by plotting Nyquist plots. These results revealed that PVDF-HFP/ZrO2 nanocomposites have shown enhanced thermal, dielectric and impedance properties as compared to neat PVDF-HFP film. These significant outcomes suggest that the PVDF-HFP/ZrO2 nanocomposites hold promise as viable options for energy storage applications. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth, but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low‐piezoelectricity polymer as employed. Herein, by combining PVDF‐HFP and ferroelectric BaTiO3, we develop a homogeneous, single‐layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength. As squeezed by local protrusion, the polarized PVDF‐HFP/BaTiO3 composite separator generates a local voltage to suppress the local‐intensified electric field and further deconcentrate regional lithium‐ion flux to retard lithium deposition on the protrusion, hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF‐HFP separator, especially at high rates. Remarkably, the homogeneous incorporation of BaTiO3 highly improves the piezoelectric performances of the separator with residual polarization of 0.086 μC cm−2 after polarization treatment, four times that of the pure PVDF‐HFP separator, and simultaneously increases the transference number of lithium‐ion from 0.45 to 0.57. Beneficial from the prominent piezoelectric mechanism, the polarized PVDF‐HFP/BaTiO3 composite separator enables stable cyclic performances of Li||LiFePO4 cells for 400 cycles at 2 C (1 C = 170 mA g−1) with a capacity retention above 99%, and for 600 cycles at 5 C with a capacity retention over 85%. [ABSTRACT FROM AUTHOR]

Iron oxide (Fe2O3) nanoparticles (NPs), graphene nanoplatelets (GNPs), and nanodiamonds (NDs) reinforced poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) nanocomposites were synthesized by a solvent casting technique. The structure and morphology of synthesized nanocomposites were studied using Fourier‐transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. The thermal behavior of polymer nanocomposites (PNCs) was studied by the thermogravimetric analysis and the derivative thermogravimetry. The dielectric measurements were carried out within the temperature range from 40 to 150°C and in the frequency range from 50 Hz to 15 MHz. At 50 Hz, 140°C, the highest dielectric constant of 92.46 was noted, for the PVDF‐HFP + 10 wt% Fe2O3 + 6 wt% GNPs + 3 wt% NDs and the highest dielectric loss tangent has been observed to be 24.75 at 50 Hz, 140°C for the PVDF‐HFP + 10 wt% Fe2O3 + 4 wt% GNPs + 2 wt% NDs. The electromagnetic interference shielding effectiveness (EMI SE) was studied in the X‐band and Ku‐band frequency regions (8–18 GHz). High EMI SE values of 31.60 dB and 34 dB were observed for PVDF‐HFP/Fe2O3/GNPs/NDs nanocomposites with 10 wt% Fe2O3 + 8 wt% GNPs + 4 wt% NDs in X‐band and Ku‐band, respectively. These findings suggests PVDF‐HFP/Fe2O3/GNPs/NDs‐based PNCs as an appealing material for EMI shielding applications. [ABSTRACT FROM AUTHOR]

Exploration of blend polymer membrane with desire performances is a highly essential research topic because it makes them as key component of the battery technologies. However, the blend membrane cannot simultaneously meet out the high electrical insulation and ion conductivity. Here, we report porous PVdF-HFP based polymer membrane blended with P123 polymer which is prepared by phase inversion technique and along with solution casting technique for comparison. Especially, the major improvements can be claimed with porous PVdF-HFP blend with P123 matrix by phase inversion process that could be mainly due to increasing the disorganize crystallinity of the PVdF-HFP, thereby enhancing the ionic conductivity of PVdF-HFP/P123 than the same prepared by traditional solution casting. More importantly, our studies reveals that, besides having an effect of crystallinity and high ionic conduction PVdF-HFP/P123 blend matrix yield homogeneous pores with higher pore density when prepared by phase inversion approach. We attribute this to remarkable enhancement in higher electrolyte uptake and higher cation transport in the blend membrane. This facilitates high ionic conductivity of 7.06 × 10−5 S/cm and electrochemical stability of 2.8 V,while the solution casting approach display low ionic conductivity of 1.63 × 10−6 S/cm and electrochemical stability of 2.2 V, respectively. A symmetric supercapacitor device is fabricated with the membrane prepared by phase inversion process, resulting in a high specific capacitance of 80 F/g at the current density of 0.25 A/g with 90.51% specific capacitance retention at 0.5 A/g. The energy density of 90.9 W/kg can be achieved at the power density of 0.375 W/kg.

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules’ immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel’s properties, and QsDSSCs’ performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications.

As a representative flexible piezoelectric polymer, polyvinylidene fluoride (PVDF) and its copolymers have been widely used in energy harvesters and piezoelectric sensors. In this work, hybrid nanocomposite films were prepared by adding a small amount of carbon black (CB) and Ni nanoparticles to the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix using the solution casting method, followed by stretching and poling to increase the electroactive β-phase content. The results show that the hybrid fillers consisting of 0.3 wt% CB and 0.1 wt% Ni nanoparticles exhibit the best piezoelectric performance. The maximum output voltage of the PVDF-HFP/CB/Ni films reaches 3.5 V under 1 mm micro-vibration, which is 75% higher than that of pure PVDF-HFP films. Characterization results by X-ray diffraction analysis, Fourier-transform infrared spectrometry, and differential scanning calorimeter analysis show that the hybrid fillers are more effective in promoting the phase transformation from the α-phase to the β-phase in the matrix due to synergistic effect.

Wrinkling phenomena has attracted wide attention owing to its applications in anticounterfeiting patterns, smart windows, flexible devices, and sensors, and the dynamic morphological transformations of wrinkle structure extend the application in dynamic displays, patterning, and surface wetting. However, developing simple and effective wrinkle morphology transformation strategies to design smart windows with good repeatability and stable properties presents ongoing challenges. In this paper, morphology transition of the wrinkle structure is presented to develop potential applications in smart window and pattern fabrication. At first, a nanoscale wrinkled structure was fabricated by immersing an ionic liquid mixed solution with poly-(vinylidene fluoride)-hexafluoropropylene over a colloidal assembly based on the mismatch modulus between the surface layer and the interior during solvent evaporation. The wrinkle structure can be erased to form a pattern by inkjet printing based on the ink-induced dispersion of the ionic liquid. Interestingly, the wrinkled and erased structures have completely opposite optical reversible responsiveness to humidity changes, which forms the basis of a smart window. This wrinkled structure shows promising applications in anticounterfeit patterning, smart windows, and antiglare materials, which provides guidelines for the development of wrinkled-based optic materials and devices. [ABSTRACT FROM AUTHOR]

Significant ultraviolet (UV) technology was used to create a new composite polymer electrolyte (CPE) membrane composed of poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), benzophenone (Bp), and varying amounts of highly ion-conducting Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles. In lithium metal batteries, the CPE membranes demonstrated improved mechanical properties as well as superior electrochemical performances. CPE-15wt% LLZTO typically demonstrated the highest ionic conductivity (σ = 3.7 × 10−3 S/cm) at room temperature, a high Li-transference (t+ = 0.79), and a wider electrochemical stability window (ESW) above 5 V, as well as good mechanical strength (8.2 MPa). More importantly, the CPE-15wt% LLZTO membrane inhibits Li dendrite expansion in Li symmetric cells and exhibits long-term cyclic stability with a current density of 3 mA/cm2 over 1150 h for Li/CPE-15wt% LLZTO/Li. The current study demonstrates that a UV-irradiated CPE membrane can be a promising electrolyte for next-generation lithium-metallic batteries. [ABSTRACT FROM AUTHOR]

Nanocomposite solid polymer electrolytes (NSPEs) with PVDF‐HFP/Pluronic as blend polymer matrix, graphene oxide (GO) as nanofiller, and LiClO4 are reported. FTIR spectroscopy reveals the crystal phase transformation of PVDF‐HFP from nonpolar α phase to electroactive γ phase upon salt addition that suggests the ion‐dipole interaction between the salt and the matrix. Further, Pluronic not only hinders the PVDF crystallization that increases the amorphous character of the matrix but also interacts with the salt and hence assists in salt dissociation in the blend matrix. The dc conductivity of PVDF‐HFP/Pluronic/LiClO4 blend SPE improves with increasing the Pluronic content reaching 0.73 × 10−6 Scm−1 at room temperature with 60 wt.% Pluronic. The dispersion of GO in the same blend SPE leads to a significant jump in room temperature ion conductivity (≈1.2 × 10−6 Scm−1) with 0.4% GO. Temperature‐dependent ion conductivity of the NSPEs reveals an Arrhenius type thermally activated process. The dc polarization data indicates that the conductivity is predominantly due to ions. Impedance plots exhibit a distorted semicircle at higher frequency and a tilted spike at lower frequency. The spike is an indication of ion diffusion and electrode polarization effect. Further, GO also has enhanced the mechanical properties of the fabricated NSPEs. [ABSTRACT FROM AUTHOR]

In this study, flexible nanocomposites made from PVDF-HFP reinforced with carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are manufactured using a sonication and solvent casting method for monitoring purposes. More specifically, the effect of the volume batch under the sonication process is explored. For CNT-based composites, the electrical conductivity decreases as the batch volume increases due to less effective dispersion of the CNTs during the 30-min sonication. The maximum electrical conductivity achieved in this type of sensor is 1.44 ± 0.17 S/m. For the GNP-based nanocomposites, the lower the batch volume is, the more breakage of nanoplatelets is induced by sonication, and the electrical response decreases. This is also validated by AC analysis, where the characteristic frequencies are extracted. Here, the maximum electrical conductivity measured is 8.66 ± 1.76 S/m. The electromechanical results also show dependency on the batch volume. In the CNT-based nanocomposites, the higher gauge factor achieved corresponds to the batch size, where the sonication may be more effective because it leads to a dispersed pathway formed by aggregates connected by tunneling mechanisms. In contrast, in the CNT-based nanocomposites, the GF depends on the lateral size of the GNPs. The biggest GF of all sensors is achieved with the PVDF-HFP/GNP sensors, having a value of 69.36 × 104 at 35% of strain, while the highest GF achieved with a PVDF-HFP/CNT sensor is 79.70 × 103 at 70%. In addition, cycling tests show robust electromechanical response with cycling for two different strain percentages for each type of nanocomposite. The sensor with the highest sensitivity is selected for monitoring two joint movements as proof of the applicability of the sensors manufactured.

Nowadays, bacterial infection is regarded as a serious threat to humankind, which needs to be taken care of. The emergence of antibiotic resistance and multidrug resistance (MDR) is rendering this situation more troublesome. However, several alternative treatment regimens have aided such diseases quite well in the recent past, among which dynamic antibacterial therapies combat this situation quite well. Among various dynamic therapies, piezodynamic therapy is a very recent avenue, in which mechanical stimuli have been exploited to treat bacterial infections. Herein, piezo-active bismuth ferrite-loaded poly(vinylidene fluoride-co-hexafluoropropylene) polymer has been utilized to eradicate gram-positive bacteria (E. faecalis) and gram-negative bacteria (E. coli). The sample has been designed in a free-standing membrane form, which, under soft ultrasound (~10 kHz), generates reactive radicals to ablate bacteria. Initially, the structure and morphology of the membrane have been substantiated by using X-ray diffraction and scanning electron microscopy methods; besides, Fourier transform infrared spectrum of the sample depicts a tremendously high value of polarizability and further confirms the piezo-activity of the membrane. More than 99% of E. coli and E. faecalis have been successfully eradicated within 30 min of ultrasound. Moreover, the solid-state structure and hydrophobic nature of the membrane help us to reuse it in a cyclic manner, which is possibly reported herein for the very first time. This novel membrane could be deployed in healthcare systems and pigment industries and could be exploited as a self-cleaning material. [ABSTRACT FROM AUTHOR]

Polymer electrolytes are being considered as an effective solution for electrochemical devices to replace currently used organic liquid electrolytes due to their excellent mechanical properties and security. Herein, we prepared stretchable polymer electrolytes (SPEs) doped with poly[(2‐acrylamido‐2‐methylpropanesulfonic acid)‐co‐poly(ethylene glycol) dimethacrylate] (P(AMPS‐co‐PEGMA)) and enhanced with poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (PVDF‐HFP), through UV in situ polymerization. The SPEs showed good mechanical performance with an elongation of more than 40% and ionic conductivity reaching the order of 10−3 S cm−1. In terms of application, flexible electrochromic devices based on the UV in situ‐prepared SPEs were assembled, the color switching performance being still good even after 400 switching cycles and 1000 bending cycles, which indicated that the SPEs could have excellent prospects in application for flexible devices. © 2023 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

This research aims to fabricate hydrophobic electrospun air filters with ultra-high performance against virions. In order to achieve this goal, constant basis weight electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) with low-bead, high-bead, and ultra-high-bead fibre structures were used to fabricate single and multilayer filters by controlling the Dimethylformamide (DMF)-to-acetone ratio of the solvent. The water contact angle of the fabricated layers ranged from 131° for low-bead structures to 135° for ultra-high-bead structures, indicating their overall high hydrophobicity. The size-resolved filtering efficiency and pressure drop tests on the fabricated filters showed that low-bead structure for both single and multilayer filters and high-bead structure for single-layer filters enhance the quality factor remarkably. The results showed that the single-layer ultra-high-bead structure air filters had a filtering efficiency of 99.33%, superior to N95 air filters (96.54%) and comparable to double N95 filters (99.86%). However, the electrospun air filter showed a pressure drop of 169.3 Pa and a quality factor of 27.6 × 10 − 3   P a − 1 compared to a pressure drop of 388 Pa and quality factor of 16.9 × 10 − 3   P a − 1 for double N95 air filters. Therefore, it has a high potential to be used as the filtration media in hospitals, long-term care centers, and masks to provide superior protection against virions for healthcare providers and patients. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) based on ionic liquid (IL) were created using poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer mixed with 30 wt.% sodium thiocynate and varying weight ratios of EMIm-TCM ranging from 0 wt.% to 300 wt.%. The structural, electrical, thermal, morphological, and electrochemical features of the SPEs films, showing the effects of PVDF-HFP and the level of IL loading, have all been carefully examined. With the addition of IL, the mechanical qualities and mechanical stability of PVDF-HFP were enhanced, getting closer to the smaller usage for liquid electrolytes in energy devices. With the addition of 300 wt.% IL, the maximum ionic conductivity of 10−3 S cm−1 was attained. Additionally, the presence of the amorphous region in the IL-based electrolyte supported the movement of the EMIm + and TCM − ions in the PVDF-HFP chains, as shown by polarized optical microscopy and the ionic transference number. Due to their strong ionic conductivity, good mechanical attributes, and potential for long-term use in electrical double-layer capacitor applications, the developed PVDF-HFP/NaSCN/EMIm-TCM complex-based SPEs are particularly promising, showing the specific capacitance of 10 Fg−1. [ABSTRACT FROM AUTHOR]

Polymer-based separators for energy storage applications are being developed to ensure the high safety, high performance, light weight, and low cost of the device. In this regard, poly(vinylidene fluoride-co-hexafluoropropylene) PVDF-HFP which is a co-polymer of PVDF is an excellent host polymer for energy storage applications as it possess both the crystalline PVDF and the amorphous HFP groups leading to both mechanical stability and ionic conductivity. Though the lithium-ion-conducting PVDF-HFP membranes are successfully utilized as the polymer electrolyte for lithium ion batteries, the enhanced ionic conductivity by usage of plasticizers often degrade their mechanical and thermal stability. Where else, when incorporated with graphene oxide (GO) as the filler, the membrane electrolytes show good ionic conducting nature, with no compromise on thermal stability and mechanical stability. Incorporation of GO results in porous nature and helps in the high electrolyte retention and electrochemical stability even at high potential window. In this review article, the influence of GO with respect to structural changes, thermal stability, and electrical properties is discussed in detail, which will pave way for further new aspects in membrane modification. [ABSTRACT FROM AUTHOR]

In this work, montmorillonite (MMT) nanoclay and graphene quantum dots (GQDs) embedded poly (vinylidenefluoride‐co‐hexafluoropropylene) (PVDF‐HFP) nanocomposite films were prepared using the solution‐casting technique and characterized using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The thermal, mechanical and dielectric properties of PVDF‐HFP/MMT/GQDs nanocomposite films were also investigated. The dielectric constant (ɛ′), dielectric loss (ɛ″) and conductivity (σ) of synthesized nanocomposite films were evaluated in the frequency and temperature range f100 Hz–1 MHz and 30–150°C, respectively. The highest ɛ′ with relatively high ɛ″ was achieved at low frequency for increasing temperature for all the nanocomposite films. The conductivity results showed good increment from lower to higher frequency up to 100 kHz at increasing temperature. The Cole–Cole plots represent the complex impedance of PVDF‐HFP/MMT/GQDs nanocomposites at 150°C. The attained results imply that the PVDF‐HFP/MMT/GQDs nanocomposite films can be useful candidates for flexible electronic devices. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes (GPEs) incorporate both the high ionic conductivity of organic liquid electrolyte and the high safety performance of all‐solid‐state electrolytes (ASSEs), greatly improving the electrochemical performance of solid polymer electrolytes (SPEs). However, the practical application of GPEs is still limited by inferior interface compatibility, lithium dendrites, etc. Herein, we prepared GPEs based on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) further co‐blended the two‐dimensional sheet inorganic filler hectorite and poly(methyl methacrylate) (PMMA) to improve the mechanical and electrochemical properties of the GPEs. When the content of PMMA and hectorite is optimal, this GPEs have an ionic conductivity of 1.06×10−3 S cm−1 and outstanding lithium symmetric cells cycle time of more than 3000 h, indicating that the introduction of filler effectively inhibits the growth of lithium dendrites at room temperature. Moreover, the GPEs adopt a relatively simple solution casting method to provide a fresh idea for the synthesis of high‐performance GPEs. [ABSTRACT FROM AUTHOR]

This paper presents and compares films made using the solution casting method with a mixture of poly (vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP), graphene oxide (GO), and lead zirconate titanate (PZT). The Hummers' method synthesized GO. Scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and tensile testing were realized. The developed composite films were found to have a coherent distribution of PZT and GO in PVDF‐HFP. After that, a gradual improvement, such as an increase in the quantity of β phase, produces high piezoelectric performance. Also, the PVDF‐HFP polymer's thermal stability improved. When 0.1 wt% of PZT/GO was added, the melting temperature increased from 140 to 143°C, and the crystallization temperature from 109 to 113°C. PVDF‐HFP elastic modulus and tensile strength were also considerably reduced as PZT/GO increased. As a result, this has enabled us to develop composite films with important properties that can be used as piezoelectric materials for energy harvesting. [ABSTRACT FROM AUTHOR]

Lithium-ion conducting solid electrolytes has been playing a vital role in designing solid-state lithium batteries to provide a propitious solution for the upcoming generation of energy storage devices that need to store more energy with a high degree of safety. Among different lithium-ion conductors, Li1.5Al0.5Ti1.5(PO4)3, a NASICON-type ceramic, has received attraction due to its good air stability and high lithium-ion conductivity. Herein, tellurium incorporated lithium aluminum titanium phosphate (Li1.3Al0.3Te0.03Ti1.67(PO4)3) (LATTP) has been prepared by solid-state reaction method. Further, the various amounts of LATTP incorporated electro-spun composite polymer electrolytes are prepared by using poly(vinylidenefluoride-hexafluoropropylene) (PVdF-HFP) polymer. Herein, we observed that 8 wt% of LATTP incorporated PVdF-HFP composite polymer electrolyte (CPE-8) exhibited high ionic conductivity of 1.9 × 10−3 S cm−1 at 30 °C, and enhanced lithium dendrite suppression and relatively lesser interfacial stability issues. Remarkably, LATTP incorporated CPE-8 shows improved cycling performance over 200 cycles compared to LATTP free (CPE-0). [ABSTRACT FROM AUTHOR]