Polyvinylidene Fluoride Polymer Research Articles

Tuning Ba/Sr ratios of BaxSr1-xTiO3 of polymer nanocomposites toward significant enhancement of energy storage performance by optimized phase composition

The rapid development of portable electronic equipment, hybrid electric vehicles and pulse power systems have put forward higher requirements for new dielectric materials, making flexible polymer dielectrics attractive. Barium strontium titanate nanoparticles with different compositions were successfully prepared by using oxalate. A series of PVDF/BaxSr1-xTiO3 nanoparticles nanocomposites were prepared using the semi-crystalline ferroelectric polymer polyvinylidene fluoride PVDF as the polymer matrix. The microstructure and electrical properties of the nanocomposites were characterized to explore the effects of the composition and intrinsic properties of the filling phase on the nanocomposites. Among all the groups of nanocomposites, the 1 vol% PVDF/Ba0.6Sr0.4TiO3@DA NPs has the highest discharge energy density at the breakdown field strength, which is 7.8 J/cm3. The excellent discharge energy efficiency of 1 vol% PVDF/Ba0.6Sr0.4TiO3@DA NPs is maintained at 65 % at 300 kV/mm. This paper can provide experimental guidance and theoretical basis for the development of high energy storage density dielectric materials and their application in dielectric energy storage capacitors.

Flexible Piezoelectric Tactile Sensor With Cilia-Inspired Structures Based on Electrospun PVDF/Fe3O4 Nanofibers

Flexible tactile sensors have promising applications at the field of intelligent robotics. However, manufacturing flexible tactile sensors with excellent stability and high sensitivity remain a great challenge. In the present work, polyvinylidene fluoride (PVDF)-based nanofibers are prepared by electrospinning loaded with Fe3O4 nanoparticles (NPs). X-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared spectroscope (ATR-FTIR) results indicate that the addition of Fe3O4 NPs promotes the generation of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -phase in PVDF polymer, which greatly improves piezoelectric properties of composite nanofibers. Simultaneously, a flexible piezoelectric tactile sensor with cilia-inspired structures (PTSCS) based on PVDF/Fe3O4 nanofibers is proposed, which consists of the substrate with cilia structures, Ag electrodes, composite nanofiber membrane, and nanofiber protective layer. The PTSCS demonstrates a higher output voltage compared to sensors with bump and planar structures, which also exhibits high robustness, with a stable output after 30000 cycles of vibration testing. More importantly, the PTSCS demonstrates superior performance in recognizing surface texture and temperature of objects. The flexible PTSCS has potential use in areas such as intelligent soft robotics and material recognition.

Functional properties of PVDF-based NZF-BT flexible films

Flexible multiferroic composite films are perspective materials for sensors, actuators and similar components of wearable and stretchable devices. Here we present the study of functional properties of flexible composites prepared by embedding nickel zinc ferrite and barium titanate powder into polyvinylidene fluoride (PVDF) polymer optimizing the ratio of polymer and fillers to get the best flexibility and functionality. ATR-FTIR analysis revealed that hot pressing of the flexible films caused a transformation of about 38% of the electro-inactive PVDF α phase into electrically active β and γ phases. Broadband dielectric spectroscopy revealed two relaxation processes responsible for PVDF and space charge relaxations. Activation energies of both processes and the freezing temperature of PVDF to the glass phase were estimated for all films. Ferroelectric measurements have shown unsaturated hysteresis loops for all samples, although the clear dependence of the amount of the electrically active phase on polarization values of composites is visible.

Scalable Fabrication of MXene-PVDF Nanocomposite Triboelectric Fibers via Thermal Drawing.

In the data-driven world, textile is a valuable resource for improving the quality of life through continuous monitoring of daily activities and physiological signals of humans. Triboelectric nanogenerators (TENG) are an attractive option for self-powered sensor development by coupling energy harvesting and sensing ability. In this study, to the best of the knowledge, scalable fabrication of Ti3 C2 Tx MXene-embedded polyvinylidene fluoride (PVDF) nanocomposite fiber using a thermal drawing process is presented for the first time. The output open circuit voltage and short circuit current show 53% and 58% improvement, respectively, compared to pristine PVDF fiber. The synergistic interaction between the surface termination groups of MXene and polar PVDF polymer enhances the performance of the fiber. The flexibility of the fiber enables the weaving of fabric TENG devices for large-area applications. The fabric TENG (3 × 2 cm2 ) demonstrates a power density of 40.8mW m-2 at the matching load of 8 MΩ by maintaining a stable performance over 12 000 cycles. Moreover, the fabric TENG has shown the capability of energy harvesting by operating a digital clock and a calculator. A distributed self-powered sensor for human activities and walking pattern monitoring are demonstrated with the fabric.

One-Step Insulating Oil Reclamation by PVDF/PTFE Composite Nanofibers

Insulating oil is indispensable cooling impregnation and isolation agent for oil-filled electrical equipment, such as power transformers. The aging byproducts, i.e., water and organic acids, impose a serious threat to these expensive transformers. Insulating oil reclamation is a complicated process. In this article, a polyvinylidene fluoride (PVDF) polymer with polytetrafluoroethylene (PTFE) additive composite nanofiber membrane is synthesized for insulating oil reclamation with high efficiency. The reclamation and dielectric performance of the PVDF/PTFE nanofiber membrane is evaluated by the acid value, microwater (MW) contents, and ac breakdown voltage of the treated oil. The results show that the nanofiber membrane filtration rate toward acetic acid and MW is 69.4% and 76.0%, respectively. Moreover, the dielectric loss factor and relative permittivity of treated oil decrease significantly at low frequencies, and the breakdown voltage is increased from 21.8 to 65.2 kV. The PVDF/PTFE composite nanofiber membrane has removed organic acid and MW effectively, and it provides a more practical method for insulating oil reclamation.

Investigation of continuous PAN nanofiber yarn produced with polymer additives

Nanofiber yarns were produced by electrospinning technique from polyacrylonitrile (PAN), thermoplastic polyurethane (TPU) added and polyvinylidene fluoride (PVDF) added PAN polymer solutions. The effects of the other polymers as additive to PAN nanofiber yarn are investigated. SEM, stress-strain characterizations were carried out. A sample plain fabric was woven from PAN nanofiber yarns to show that nanofiber yarns are feasible and can be integrated into conventional textile structures. Addition of the other polymers has increased the Young modulus by 40%, whereas TPU addition has increased the tenacity by 50% but TPU + PVDF addition has decreased the tenacity by half of only PAN. Breaking elongation was slightly decreased by the addition of TPU and PVDF polymers.

Piezo-, photo- and piezophotocatalytic activity of electrospun fibrous PVDF/CTAB membrane

A composite material based on polyvinylidene fluoride (PVDF) nanofibers modified with cetyltrimethylammonium bromide (CTAB) was synthesized by coaxial electrospinning. The morphology and structure of the material were studied by SEM, FTIR spectroscopy, X-ray diffraction analysis, XPS, and the piezo-photo- and piezo-photocatalytic activity during the decomposition of the organic dye Methylene blue (MB) was studied. It is shown that the addition of CTAB promotes additional polarization of the PVDF structure due to ion-dipole interaction. It has been shown for the first time that the addition of CTAB promotes the photosensitivity of the wide-gap dielectric polymer PVDF (the band gap is more than 6 eV). It was demonstrated that the photocatalytic decomposition efficiency was 91% in 60 minutes. The material exhibits piezocatalytic activity – 73% in 60 minutes. Experiments on trapping active oxidizing forms have established that OH hydroxyl radicals play the main role in the photocatalytic process.

The Effectiveness of Polyvinylidene Fluoride Membranes Modified with Poloxamer and Single/Multi-Walled Carbon Nanotubes for Lactalbumin Purification

The application of separation technology using ultrafiltration/nanofiltration membranes for protein purification and concentration has grown rapidly in the last decade. Innovations to synthesize membranes with properties and performance that suit the characteristics of the feed solution have been and will keep developing. This study aims to examine the strategies to improve the performance of the Polyvinylidene Fluoride (PVDF) membrane for lactalbumin protein isolation. The PVDF polymer membrane was modified by adding Poloxamer 188 (Po1) copolymer and a combination of two types of nanocarbons, i.e., single-walled carbon nanotubes (S-CnT) and multi-walled carbon nanotubes (M-CnT). The following membrane characteristics were examined: mechanical properties, morphological structure, porosity, elemental composition and functional groups, and surface hydrophilicity. The membrane’s filtration performance was analyzed in terms of its ability to pass water (flux) and concentrate lactalbumin protein. The results showed that the changes in the membrane morphological structure were clearly visible in the SEM test, which exposed more open membrane pores after adding Pol and S-CnT/M-CnT additives. The mechanical properties of the membrane also increased, as indicated by the increase in the tensile strength from 12.1 MPa to 16.07 MPa. In general, it was found that the composition of the PVDF/Pol/S-CnT/NMP polymer solutions resulted in better filtration performance compared to the membranes made of only the PVDF/NMP polymer solution.

Structure-Property Relationship of Piezoelectric Properties in Zeolitic Imidazolate Frameworks: A Computational Study.

Metal-organic frameworks (MOFs) are a class of nanoporous crystalline materials with very high structural tunability. They possess a very low dielectric permittivity εr due to their porosity and hence are favorable for piezoelectric energy harvesting. Even though they have huge potential as piezoelectric materials, a detailed analysis and structure-property relationship of the piezoelectric properties in MOFs are lacking so far. This work focuses on a class of cubic non-centrosymmetric MOFs, namely, zeolitic imidazolate frameworks (ZIFs) to rationalize how the variation of different building blocks of the structure, that is, metal node and linker substituents affect the piezoelectric constants. The piezoelectric tensor for the ZIFs is computed from ab initio theoretical methods. From the calculations, we analyze the different contributions to the final piezoelectric constant d14, namely, the clamped ion (e140) and the internal strain (e14int) contributions and the mechanical properties. For the studied ZIFs, even though e14 (e140 + e14int) is similar for all ZIFs, the resultant piezoelectric coefficient d14 calculated from piezoelectric constant e14 and elastic compliance constant s44 varies significantly among the different structures. It is the largest for CdIF-1 (Cd2+ and -CH3 linker substituent). This is mainly due to the higher elasticity or flexibility of the framework. Interestingly, the magnitude of d14 for CdIF-1 is higher than II-VI inorganic piezoelectrics and of a similar magnitude as the quintessential piezoelectric polymer polyvinylidene fluoride.

The Electromagnetic Interference Shielding Effectiveness and Dielectric Response of PVDF-nTiO2Nanocomposites Thin Films

This paper presents electromagnetic interference (EMI) shielding effectiveness (SE) and dielectric response of Polyvinylidene Fluoride (PVDF) and PVDF-Titanium dioxide (nTiO2) nanocomposite thin films. nTiO2 nanoparticles were synthesized by the combustion method using urea as fuel. PVDF and PVDF-nTiO2nanocomposite thin films of different wt% of TiO2as fillers in the PVDF matrix were prepared using the solvent evaporation method. The synthesized nanocomposite thin films were characterized by XRD, FTIR, and SEM. The EMI-SE was studied in the frequency range 0.5 - 8GHz and dielectric response in 10Hz - 8MHz at room temperature. The EMI-SE shows up and down valleys in S-Band with an average variation of ⁓28 and ⁓35 dB at 2 and 4GHz respectively and remains stable in C- Band agreeing with existing literature. The dielectric constant of PVDF-nTiO2 nanocomposite thin films decreases with an increase in frequency and anomaly for 10wt% of nTiO2 fillers in the PVDF matrix at standard frequency. HIGHLIGHTS TiO2 nanoparticles were synthesized by the combustion method using urea as fuel PVDF and PVDF-nTiO2 composites were prepared using the solvent evaporation technique The addition of nanoparticles to the PVDF polymer has varied the EMI shielding and dielectric properties of nanocomposite thin films The observed variations in EMI-SE and dielectric constant with frequency are discussed in terms of the dynamics of domain switching GRAPHICAL ABSTRACT

A non-destructive technique using digital holographic vibrometry and Lamb waves for quality determination of polymer-metal laminates

We used digital holographic vibrometry (DHV) as a non-destructive method to detect debonding areas in laminates made of aluminum and polymer (polylactide, polyvinylidene fluoride or polycarbonate). At low frequencies (up to 30 kHz) A_0 Lamb waves were excited and the amplitude and the phase patterns of the vibration of the sample were simultaneously registered for metal and polymer side of the laminate. Based on these patterns debonding areas in laminates were localized. The transmission properties at low frequencies were also studied in terms of: the frequency range for which regular Lamb waves have been observed, Lamb wave amplitudes and Lamb wave propagation velocity depending on the frequency. We have shown that these properties also change when a defect occures in the laminate. Even when we could not localize the defect it was still possible to detect if a sample was damaged based on the behaviour of the Lamb waves.

Electrochemical quantification of atrazine-fulvic acid and removal through bismuth tungstate photocatalytic hybrid membranes

Herbicides such as atrazine and humus substances such as fulvic acid are widely used in agricultural sector. They can be traced in surface and groundwater around the agriculture field at concentrations beyond the approved limit due to their mobility and persistence. Bismuth-based photocatalysts activated by visible light are potential materials for removing various organic pollutants from water bodies. These photocatalysts can also be suitable candidates for developing a hybrid membrane with anti-fouling properties. In this study, Bi2WO6 nanoparticles were synthesized via the hydrothermal method and integrated into the cellulose acetate (CA), polyetherimide (PEI), polysulfone (PSF) and polyvinylidene fluoride (PVDF) polymers via physical blending approach. The hybrid membranes were then characterized by FTIR, XPS and FESEM to confirm the chemical bonding, chemical composition and surface morphology of Bi2WO6. Thus, the pure water flux of CA (35.6 L m−2 h−1), PEI (46.56 L m−2 h−1), PSF (6.84 L m−2 h−1), and PVDF (68.47 L m−2 h−1) hybrid membranes has significantly enhanced than the pristine CA, PEI, PSF and PVDF membranes. The significant rejection of atrazine-fulvic acid was observed with hybrid membranes in the order of CA (84.1%) > PVDF (72.7%) > PEI (47.8%) > PSF (37.2%), and these membranes have shown an excellent flux recovery ratio than pristine membranes. Further, electrochemical quantification studies were performed to analyze the removal efficiency of atrazine-fulvic acid from water. In this present work, GO-modified SPE was employed for electrochemical sensing studies. The resultant CA hybrid membrane achieved removal efficiency of 84.08% for atrazine. It was observed that the Bi2WO6 established strong bonding with CA, and PVDF membranes, thus showing a significant removal efficiency and FRR than other hybrid and pristine membranes.

Humidity Sensor to Support Dry Eye Diagnosis Based on Polymeric PVDF Transfer Membrane

A system based on polyvinylidene fluoride (PVDF) polymeric transfer membrane was developed as an ocular humidity sensor to support the diagnosis of dry eye. An experimental arrangement was implemented where the devices utilized to observe the behavior of PVDF transfer membrane as a humidity sensor were installed, on the contour of an artificial eye model, held with a contact lens, formed by an elastic balloon that is exposed to triple distilled water and artificial tears, on the order of 0– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$40~\mu \text{L}$ </tex-math></inline-formula> , with a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~\mu \text{L}$ </tex-math></inline-formula> . Measures were taken simulating four constant intraocular pressures (IOPs), i.e., 10, 15, 20, and 25 mmHg. The pressure exerted on both elastic artificial eyes is done simultaneously through communicating vessels. Similarly, the IOP of the artificial eye was recorded using a Schiötz tonometer and an MPX2010 GP sensor, in the range of 10–25 mmHg. The response of the PVDF transfer membrane showed a proportional relationship between capacitance changes and humidity (lack of humidity or dryness) in the artificial eye model. Capacitance measurements were made at room temperature at 25 °C, using an HM818-Rohde and Schwarz bridge <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit {LCR}$ </tex-math></inline-formula> meter. Finally, capacitance response was converted to frequency with an astable oscillator to optimize signal processing and visualization. These polymeric PVDF transfer membranes sensors are a hydrophobic material, which prevents the storage of water molecules in the sensing material and allows liquid or artificial tears to flow freely. In summary, polymeric PVDF transfer membranes exhibit suitable properties as a dry eye humidity sensor at realistic IOPs.

Piezoelectric Nanogenerator Based on Electrospinning PVDF/Cellulose Acetate Composite Membranes for Energy Harvesting.

The organic piezoelectric polymer polyvinylidene fluoride (PVDF) has attracted extensive research because of its excellent flexibility and mechanical energy-harvesting properties. Here, the electrospinning technique was taken to fabricate synthesized fiber membranes of a PVDF/cellulose acetate (CA) composite. The obtained PVDF/CA electrospun fiber membranes (EFMs) were employed to prepare a flexible nanogenerator. XRD and FTIR spectroscopy revealed the enhancement of piezoelectric behavior due to an increase in β-phase in PVDF/CA EFMs compared with cast films. The PVDF/CA fibers (mass ratio of PVDF to CA = 9:1) showed an output voltage of 7.5 V and a short-circuit current of 2.1 μA under mechanical stress of 2 N and frequency of 1 Hz, which were 2.5 and two times greater than those of the pure PVDF fibers, respectively. By charging a 4.7 µF capacitor for 15 min with the voltage generated by the PVDF/CA EFMs, nine LED lamps could be lit. The work provides an effective approach to enhancing the piezoelectric effects of PVDF for low-power electronic loading of macromolecule polymers.

Electrochemical and Structural Study on PVDF-Based Polymer Electrolytes for Solid-State Batteries

Lithium-ion batteries are widely used today in powering devices from portable electronics to electric vehicles. Despite their great success, this battery chemistry relies on organic solvent-based liquid electrolytes which are highly flammable, leading to major safety concerns. In contrast, solid-state batteries, which are based on solid-state electrolytes, are regarded to have much better safety characteristics and potentially higher energy density than the conventional lithium-ion batteries. Solid-state electrolytes usually include ceramics, polymers, gels, and composites. Among them, polymer materials have attracted considerable attention due to their great interfacial contact, flexibility, and easy fabrication. In particular, polyvinylidene fluoride (PVDF) polymer electrolyte is a promising candidate as it can potentially provide a high voltage window and enable high energy density solid-state batteries. However, the current PVDF-based polymer electrolyte is still not compatible with high voltage cathodes, such as layered lithium transition metal oxides and the interaction between the salt and PVDF polymer has not been fully elucidated.We have systematically studied the PVDF-based electrolytes with different salts and salt combinations, including lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(pentafluoroethanesulfonyl)imide (LiBETI). The optimized electrolyte delivers excellent performance for solid-state Li||LiFePO4 cells, achieving a specific capacity of over 150 mAh/g and lasting more than 50 cycles with over 99% capacity retention. Similar tests have also been applied to lithium nickel manganese cobalt oxides (NMC), and the preliminary results show promising cycling stability and capacity retention. In addition to electrochemical study, we employed a range of synchrotron-based X-ray techniques, including diffraction, pair distribution function analysis, and absorption spectroscopy, to investigate the interactions between the polymer and lithium salt in the polymer electrolytes. This knowledge will provide valuable information for designing new polymer electrolyte systems.Acknowledgments: The work at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704. This research used beamline 23-ID-2 and 28-ID-2 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.

Construction of Polyvinylidene Fluoride Buffer Layers for Li1.3Al0.3Ti1.7(PO4)3 Solid-State Electrolytes toward Stable Dendrite-Free Lithium Metal Batteries

The NASICON-type inorganic electrolyte Li1.3Al0.3Ti1.7(PO4)3 (LATP) is an ideal solid electrolyte material for solid-state batteries due to its remarkable lithium-ion conductivity, wide electrochemical window, and superb environmental stability. However, its poor contact with electrodes and incompatibility with lithium (Li) anodes cause high interfacial impedance or even electrolyte deactivation. To address these issues, a double-side-modified LATP ceramic pellet with a flexible polyvinylidene fluoride (PVDF) polymer electrolyte capable of promoting LATP/electrode interfacial contact and synchronously modifying LATP/Li interfacial compatibility is constructed. The results demonstrate that the introduction of the PVDF buffer layers effectively reduces the interface impedance (5789 Ω → 271 Ω), prevents the occurrence of unwanted reactions of Li anode and LATP, and thus ensures the stable operation of the battery. The Li/Li cell fabricated by PVDF-modified LATP ceramic pellet exhibits over 3000 h of stable dendrite-free cycling at 0.1 mA cm–2 and small polarization (30 mV). This solid-state LiFePO4/Li battery exhibits a capacity retention of 83.4% after 300 cycles, implying its good cycling stability. This study indicates that such an interfacial modification strategy is effective for anodic protection and contributes to the formation of stable solid-state batteries.

Synthesis of carbon nanofibers from electrospun polyvinylidene fluoride nanofibers for cathode electrodes in Li-O2 batteries

PVDF nanofibers were fabricated by the electrospinning method from polyvinylidene fluoride (PVDF) solutions in mixture of DMF and acetone solvents. PVDF fibers were then converted to CNF fibers through the low-temperature chemical stabilization ("dehydrofluorination") before carbonization at 800°C. The free-standing, perforated features of the CNF-based PVDF enabled the CNF to be directly applied as an air cathode in a LOB just after drying, without requiring additional conducting additives or polymeric binders. The interconnected pores between the individual CNFs were estimated to be 2‒4 µm. This could prevent the electrode from clogging when the discharge product was formed. With the interstitial voids and a large surface area, the CNF electrode synthesized from polymer PVDF had a capacity of 2,600 mAh/g with a current density of 200 mA/g. Moreover, CNF fibers, synthesized from electrospun PVDF nanofibers containing C‒F bonds, could improve the electrode conductivity, forming Li2O2 discharge products with less crystalline properties, leading to overpotential reduction during a discharge. This contributed to the longer cycle life of Li-O2 batteries using the CNF synthesized from electrospun PVDF nanofibers electrode (97 cycles) compared to the one synthesized from electrospun PAN nanofibers electrode (73 cycles) at a limited capacity of 1,000 mA/h and a current density of 200 mA/g. Their structure and morphology were evaluated by Scanning Electron Microscopy, Fourier-transform infrared Spectroscopy, Energy Dispersive X-ray Spectroscopy, X-ray diffraction, and Raman Spectroscopy.

CNT/PVDF Composite Coating Layer on Cu with a Synergy of Uniform Current Distribution and Stress Releasing for Improving Reversible Li Plating/Stripping.

The uncontrollable formation of polymorphous Li deposits, e.g., whiskers, mosses, or dendrites resulting from nonuniform interfacial current distribution and internal stress release in the upward direction on the conventional current collector (e.g., Cu foil) of Li metal rechargeable batteries with a lithium-metal-free negatrode (LMFRBs), leads to rapid performance degradation or serious safety problems. The 3D carbon nanotubes (CNTs) skeleton has been proven to effectively reduce the current density and eliminate the internal accumulated stress. However, remarkable electrolyte decomposition, inherent Li source consumption due to repeated SEI formation, and Li+ intercalation in CNTs limit the application of 3D CNTs skeleton. Thus, it is necessary to avoid the side effects of the 3D CNTs skeleton and retain uniform interfacial current distribution and stress mitigation. In this work, we integrate the CNTs network with a soft functional polymer polyvinylidene fluoride (PVDF) to form a relatively dense coating layer on Cu foil, which can shield the contact between the internal surface of the 3D CNTs framework and the electrolyte. Simultaneously, the Li-F-rich SEI resulting from the partial reduction of PVDF with deposited Li and the soft nature of the coating layer release the accumulation of internal stress in the horizontal direction, resulting in mosses/whisker-free Li deposition. Thus, improved Li deposition/dissolution and stable cycling performance of the LMFRBs can be achieved.

Sonocatalytic degradation of ciprofloxacin and organic pollutant by 1T/2H phase MoS2 in Polyvinylidene fluoride nanocomposite membrane

The development of recyclable catalysts with effective properties and stable reusability is great importance for the removal of different types of pollutants in wastewater. Herein, we have synthesized Polyvinylidene fluoride (PVDF) polymer and mixed-phase 1T/2H MoS2 for immobilizing the sonocatalyst material. Techniques such as FESEM, XRD, FTIR, XPS, and UV–vis spectra have been used for analyzing the structural, and morphological properties. The formation of a 1T/2H mixed phase in MoS2 has been revealed by XRD and XPS analysis. Consequently, the sonocatalytic performance of the nanocomposite membrane was investigated through ciprofloxacin (CIP) and organic pollutants (Rhodamine B (RhB)). As a result, MoS2/PVDF (PM4) nanocomposite membrane exhibited a superior sonocatalytic activity with 94.37% and 84.37% of RhB and CIP degradation efficiency with pseudo-first-order kinetic constant (k) of 0.0187 min−1, and 0.0044 min−1. The sonocatalytic property of the nanocomposite membrane is related to 1T/2H mixed-phase and PVDF. Additionally, the metallic based 1T phase MoS2 helps to promote electrons and holes and reduce the recombination rate. Moreover, it promotes the generation of more hydroxy radicals (.OH), and superoxide radicals (∙O2−) play a significant role in sonocatalytic degradation of RhB pollutants. Thus, the improved sonocatalytic degradation of 1T/2H MoS2/PVDF composite membrane exhibited its application in real-time wastewater treatment.

Electrospun polyvinylidene fluoride mats as a novel platform for dye-doped random lasing

The development of novel polymer nanofiber-based photonic devices has led to improved optical materials, extremely appealing for random lasers (RLs). Recently, electrospun polymer fibers have been proposed as convenient materials for RLs, leading to a versatile, low-cost strategy for developing new scattering materials. Here we utilize electrospun Polyvinylidene fluoride (PVDF) polymer as the system with randomness (scatterers), varying in all directions, and rhodamine 6 g (R6G) as the gain medium. A transition from amplified spontaneous emission to lasing with coherent feedback in dye-doped electrospun polyvinylidene fluoride polymer mats is observed by increasing the gain concentration from 1 mM to 3 mM. Indeed, for 3 mM dye concentration, we can observe the emergence of sharp laser peaks (where peak width narrows down to ≈ 0.2 nm), which are superimposed on the broad emission band. These results made this simple and powerful disordered platform made of R6G doped electrospun PVDF materials as valuable active media for controllable light emission, which is of paramount importance in optical sensing and for versatile microlaser devices.