Crystalline Polyvinylidene Fluoride Research Articles

ENHANCING PVDF POLYMER PROPERTIES VIA VARIED BARIUM TITANATE MORPHOLOGIES AND SYNTHESIS TECHNIQUES: REVIEW

Background: Polyvinylidene fluoride (PVDF) is widely utilized in electronic devices due to its piezoelectric properties, which can be enhanced through the incorporation of barium titanate (BT). However, the impact of various fabrication methods on the crystallinity and beta-phase content of PVDF/BT nanocomposites remains underexplored. Specific Background: Different manufacturing techniques, including 3D printing, electrospinning, solvent casting, and compression molding, influence the structural and functional properties of PVDF/BT composites. The crystallinity and beta-phase content of PVDF are critical for optimizing the dielectric and piezoelectric performance of these materials. Knowledge Gap: There is a lack of comprehensive studies comparing the effects of these fabrication techniques on the crystallinity and beta-phase enhancement of PVDF/BT composites, particularly concerning their dielectric, piezoelectric, and mechanical properties. Aims: This study aimed to investigate the impact of integrating BT into PVDF using various fabrication methods on the crystallinity and beta-phase formation. The goal was to determine how these modifications influence the material’s structural characteristics and, consequently, its electronic properties. Results: X-ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR) analyses revealed that 3D printing and electrospinning methods significantly enhanced the beta-phase content and crystallinity of PVDF/BT composites compared to solvent casting and compression molding. Scanning Electron Microscopy (SEM) confirmed improved morphological features in the PVDF matrix with these techniques. Novelty: This study provides new insights into how different fabrication methods can optimize the crystallinity and beta-phase of PVDF/BT nanocomposites, which are crucial for enhancing piezoelectric performance. Implications: The findings suggest that 3D printing and electrospinning are superior to traditional methods for fabricating PVDF/BT composites with enhanced piezoelectric properties. These results can guide the development of more efficient electronic devices by selecting appropriate fabrication techniques to achieve desired material properties.

Impact of titanium dioxide/graphene in polyvinylidene fluoride nanocomposite membrane to intensify methylene blue dye removal, antifouling performance, and reusability

AbstractThe development of efficient water purification technologies is a critical research focus driven by the crucial role of clean water sources for ecological sustainability. This study explores the strategic incorporation of nanoparticles within polyvinylidene fluoride (PVDF) membranes as a promising approach to enhance membrane performance for wastewater remediation. PVDF membranes containing varying ratios of graphene (GR) and titanium dioxide (TiO2) nanocomposites were fabricated via phase inversion method. Characterization techniques including XRD, FTIR, and FESEM‐EDX revealed that the 80% GR nanocomposite membrane exhibited desirable structural and functional properties with pronounced sponge‐like morphology and homogenous nanoparticle distribution. Fourier‐transform infrared spectroscopy and x‐ray diffraction analysis confirmed the 80% GR membrane retained PVDF crystallinity while uniquely eliminating TiO2 crystallinity. Subsequently, performance testing demonstrated the 80% GR nanocomposite membrane had the highest water flux and methylene blue dye rejection rates compared to other ratios and the pristine PVDF membrane. Both fabricated membranes exhibited sufficient reusability and antifouling properties. However, 80% GR ratio exhibited superior antifouling properties, indicating its potential as an optimal material for improving membrane hydrophilicity and overall water purification technologies. These findings underscore the strategic utility of GR‐TiO2 nanocomposites for enhancing PVDF membrane performance in sustainable wastewater treatment applications.

Synthesis and characterization of FMWCNTs/ZnO doped PVDF nanocomposites for enhanced mechanical, dielectric, and radiation shielding properties

This study investigates the enhancement of radiation shielding properties of polyvinylidene fluoride (PVDF) through the incorporation of functionalized multi-walled carbon nanotubes (FMWCNTs) and zinc oxide nanoparticles (ZnONPs), aiming to develop a lightweight, effective, and environmentally friendly shielding material. PVDF-based nanocomposites with varying concentrations of FMWCNTs@ZnO (0.0, 0.5, 1.0, 1.5, and 3.0 wt%) were synthesized using a solution casting method. Morphological analysis via high-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) confirmed the uniform dispersion of FMWCNTs@ZnO within the PVDF matrix. X-ray diffraction (XRD) studies revealed an increase in the β-phase crystallinity of PVDF at 1 wt% FMWCNTs@ZnO concentration, with a notable peak shift indicating enhanced polar group development. Vickers microhardness tests showed a significant improvement, with hardness values increasing from 342.5 kg/mm2 for pure PVDF to 391.2 kg/mm2 for nanocomposites containing 3 % FMWCNTs@ZnO. Dielectric analyses demonstrated increased permittivity and a dynamic relaxation behavior indicative of improved charge carrier density and interfacial polarization. Gamma shielding efficiency, assessed through linear attenuation coefficients (GLAC) and mass attenuation coefficients (GMAC), exhibited superior performance at lower photon energies (80 keV), with the highest GLAC and GMAC values observed for the 3 wt% FMWCNTs@ZnO doped samples. These findings underscore the potential of FMWCNTs@ZnO doped PVDF nanocomposites as promising materials for radiation shielding applications, offering a synergistic approach to enhancing mechanical, dielectric, and protective properties against ionizing radiation.

High-capacity all-solid-state lithium battery with stable interfaces enabled by ultra-thin polyvinylidene fluoride/Li3InCl6 composite solid electrolyte

The practical application of all-solid-state lithium batteries (ASSLBs) is inhibited by the poor ionic conduction of solid electrolytes and the large interfacial resistance in ASSLBs. To solve these issues, a simple sol-gel and coating process is developed to prepare self-standing ultra-thin composite solid electrolytes with polyvinylidene fluoride (PVDF) as the matrix and Li3InCl6 (LIC) as the inorganic filler. The introduction of LIC can effectively reduce the crystallinity of PVDF, provide new Li+ migration channels and enhance the ion conductivity of the electrolyte. The flexible PVDF matrix can improve the interfacial contact between the electrolyte and electrodes to promote uniform Li deposition. The constructed PVDF/LIC electrolyte not only reduces the interface impedance but also produces good mechanical strength to inhibit the growth of lithium dendrites, thus exhibiting good electrochemical performance. The assembled Li|PVDF/LIC-15%|LiFePO4 ASSLBs have a high capacity of 161.8 mAh g−1 with a capacity retention of 82.8% after 200 cycles. In addition, the PVDF/LIC electrolyte can be assembled with the high-voltage cathode (NCM811) to form ASSLBs. The proposed preparation method is simple, safe, and has good practical application prospects.

Effects of solvents on Li+ distribution and dynamics in PVDF/LiFSI solid polymer electrolytes: An all-atom molecular dynamics simulation study

Large-scale all-atom molecular dynamics simulations are used to investigate the structure and dynamics of a solid polymer electrolytes (SPE) model made up of polyvinylidene fluoride (PVDF) as the polymer matrix, lithium bis(fluorosulfonyl)imide salt (LiFSI), and six distinct solvent types in varying quantities. The influence of solvents on the physicochemical parameters of SPEs relevant to the Li-Battery sector is analysed. We prove that the presence of solvents containing oxygens atoms has different abilities to dissociate the LiFSI ions, form confined channels in the SPEs, and decrease the PVDF crystallinity. Besides, some solvents having a high affinity to the cations reduce the Li+ transport assembling in nano-domains, separated from the PVDF chains, when they present with a high amount, dramatically decreasing the Li+ transference number (tLi+). On the contrary, the ionic conductivity boosts preserving a good tLi+ for high dynamics solvents that form small Li+-solvent clusters. Our nanoscale investigations edify approaches for improving the ionic conductivity and controlling the arrangement of the ions in the SPE needed for proper battery operation by choosing a suitable solvent with a regulated amount.

Improved Electrical Signal of Non-Poled 3D Printed Zinc Oxide-Polyvinylidene Fluoride Nanocomposites.

Polyvinylidene fluoride (PVDF) presents highly useful piezo and pyro electric properties but they are predicated upon the processing methods and the ensuing volume fraction of the β-phase. Production of PVDF with higher β-phase content for additive manufacturing (AM) is particularly desirable because it can enable the creation of custom parts with enhanced properties. Necessary steps from compounding to the testing of a 3D printed piezo sensitive sensor are presented in this paper. AM process variables and the influence of zinc oxide (ZnO) nanofiller on crystallinity, viscosity, and electromechanical properties of PVDF, have been explored. Fourier-transform infrared spectroscopy (FTIR) measurements confirm that a high cooling rate (HCR) of 30 °C min−1 promotes the conversion of the α-into the β-phase, reaching a maximum of 80% conversion with 7.5–12.5% ZnO content. These processing conditions increase the elastic modulus up to 40%, while maintaining the ultimate strength, ≈46 MPa. Furthermore, HCR 10% ZnO-PVDF produces four times higher volts per Newton when compared to low cooling rate, 5 °C min−1, pristine PVDF. A piezoelectric biomedical sensor application has been presented using HCR and ZnO nanofiller. This technique also reduces the need for post-poling which can reduce manufacturing time and cost.

Enhanced piezoelectric and photocatalytic performance of flexible energy harvester based on CsZn0.75Pb0.25I3/CNC–PVDF composite nanofibers

Synthesizing the lead toxicity reduced inorganic perovskite quantum dots (IPQDs) using eco-friendly cellulose nanocrystals (CNC) ligands and mixed with the ferroelectric polymer (polyvinylidene fluoride (PVDF)) for the piezoelectric and photo induced pyrocatalytic applications. IPQDs incorporated PVDF nanofiber render excellent piezoelectricity and intriguingly benefitted with pyro catalytic behavior which becomes the potential of new reusable and toxic-free pyrocatalysts for organic pollution treatments. • Crystallinity of PVDF enhanced with CsPb 0.25 Zn 0.75 I 3 /CNC quantum dot fillers. • Highly flexible and sensitive PPNG device applied to track the human body motions. • The PPNG produces a maximum power density of 29 μm cm −3 with 8 MΩ resistive load. • Photo pyrocatalytic activity of PPNG is investigated by oxidizing Rhodamine dye. The development of high-performance, bio-energy-harvesting and green energy production materials remains a major objective. Perovskite quantum dots have been recently emerging as a potentially relevant material because of their outstanding optoelectronic properties; however, some issues regarding instability and environmental impact remains as stumbling blocks. This research presents a promising and facile method for incorporating lead toxicity reduced inorganic perovskite quantum dots (IPQDs; CsPb 0.25 Zn 0.75 I 3 ) with eco-friendly cellulose nanocrystal (CNC) ligands into polyvinylidene fluoride (PVDF) electrospun nanofibers (PPNG) forming potential piezoelectric and pyroelectric applications. Applying distinct pressures through finger tapping, air pressure, hand bending, fist beating, and foot striking generates intriguing self-powered energy harvesting sensory performances. PPNG produces stable and sensitive signals with highest open-circuit voltage of 20.3 V, short circuit current of 1.2 μA cm −2 , and power density of 29.0 μW cm −3 . Furthermore, the material was found to be successful in pyrocatalytic decay of Rhodamine-B dye; the maximum dye decay was 91% and it exhibits five reusable cycles with ultra-low lead leakages (<1 ppm) because of the photo thermal property of the IPQDs, and excellent stability offered by dual encapsulation. The wearable and durable performances exhibited by the PPNGs can potentially bring limelight in the fabrication of scalable wearable optoelectronic device.

Method for fabricating highly crystalline polyvinylidene fluoride for piezoelectric energy-harvesting and vibration sensor applications

Humidity controlled preparation of highly crystalline polyvinylidene fluoride (PVDF) films for energy-harvesting and sensor applications.

USING PERCOLATIVE CRYSTALLINE 0.3 CUO/PVDF NANOCOMPOSITE GATE DIELECTRIC FOR FABRICATING HIGH-EFFECT MOBILITY THIN FILM TRANSISTOR OPERATING AT LOW VOLTAGE

Thin-film transistor (TFT) with various layers of crystalline Poly-vinylidene fluoride (PVDF)/CuO percolative nanocomposites based on Anthracene as a gate dielectric insulator have been fabricated. A device with excellent electrical characteristics at low operating voltages (&lt;1V) has been designed. Different layers (L) of the film were also prepared to achieve the best optimization of ideal gate insulator with various static dielectric constants (εr). Capacitance density, leakage current at 1V gate voltage and electrical characteristics of OFETs with a single and multi layer films have been investigated. This device was showed highest field effect mobility of 2.27 cm2/Vs, a threshold voltage of -1.6V, an exceptionally low sub threshold slope of 380 mV/decade and an on/off ratio of 106. Such a High-ε three layered (3L) PVDF/CuO gate dielectric appears to be highly promising candidates for organic non-volatile memory, sensor and field-effect transistors (FETs).

3D Printing of Polyvinylidene Fluoride Based Piezoelectric Nanocomposites: An Overview

AbstractRecently, polyvinylidene fluoride (PVDF) based nanocomposites have attracted much attention for next‐generation wearable applications such as promising piezoelectric energy harvesters (nanogenerators), energy storage devices, sensing devices, and biomedical devices due to their high flexibility, and high dielectric and piezoelectric properties. 3D printing technology, PVDF based piezoelectric nanocomposites, the studies based on 3D printing of PVDF based piezoelectric nanocomposites by inkjet printing and fused deposition modeling, and enhancements of energy harvesting and storage performance of nanocomposites by structural design are comprehensively overviewed here. An insight is provided into 3D printing techniques, structure and properties of PVDF based polymers, various nanofillers and production methods for nanocomposites, solutions to enhance β phase (crystallinity) of PVDF, and improvements of nanocomposites’ breakdown strength, discharged energy density, and piezoelectric power output by mentoring structural design.

Crystallinity and β Phase Fraction of PVDF in Biaxially Stretched PVDF/PMMA Films.

Polyvinylidene fluoride (PVDF) and poly(methyl methacrylate) (PMMA) blend films were prepared using biaxial stretching. The effects of PMMA content and stretching ratio on the crystallinity and β phase fraction of PVDF in blend films were investigated. The distributions of crystallinity and β phase fraction on variable locations were also studied. The results of FTIR and XRD showed that β phase appeared in PVDF/PMMA blends after extrusion and casting procedures. Although β phase fraction decreased after preheating, there was still an increasing trend during following biaxial stretching. More importantly, the increase in PMMA content improved β phase fraction, and the highest β phase fraction of 93% was achieved at PMMA content of 30 wt% and stretching ratio of 2×2. Besides, the reduction in PMMA content and the increase in stretching ratio improved the crystallinity of PVDF. The mechanical properties of the stretched films were significantly improved by increasing the stretching ratio as well. The uniform stress distribution on different regions of biaxial stretching films contributed to the uniform distribution of β phase fraction and crystallinity of PVDF with the aid of simulation. This work confirmed that biaxial stretching can be a candidate method to prepare PVDF/PMMA blend films with uniform distributions of comparable β phase and crystallinity of PVDF.

Improved under damped oscillator properties of polymer blends for electronic applications

Modified polymer blends demonstrated the desirable properties and performance suitable for various applications. In the present investigation, we prepared the blends of crystalline Polyvinylidene fluoride (PVDF)/ with amorphous Polysulfone (PSF) by a solution technique. We have foreseen the miscibility of the PVDF/PSF polymer system by an optical polarizing microscope. The electrical quality factor (Q) of these polymer blends demonstrated increased quality magnitude with the shift in resonance frequency ( $f_{0}$ ) and bandwidth (B.W.) confirmed by an impedance analyzer. The influence of the temperature on the quality factor was studied across the temperature scale (30 to 150 ∘C). This investigation was feasible for the development of a new class of polymer blends deployable for electronics and shielding applications.

Enhanced structure, dielectric, and thermal properties of attapulgite clay and hexagonal boron nitride admixture loaded polymer blends

Polyvinylidene fluoride (PVDF) and poly methyl methacrylate (PMMA) polymer blends were prepared by loading optimized quantity of attapulgite clay (AT) and hexagonal boron nitride (h-BN) nanopowder admixture. The crystalline phases were confirmed by X-ray diffraction patterns owing to the crystallinity of PVDF and h-BN. The shape and dimension of AT and h-BN fillers were confirmed by transmission electron microscope. The morphological changes were confirmed by scanning electron microscope, and the chemical composition of elements in the blends was confirmed by energy-dispersive spectroscopy. Frequency-dependent dielectric properties of the mixtures were explored as a function of temperature. The dielectric constant (er) was improved (~ 6.87) when the AT and h-BN were loaded in an equal ratio (5:5 wt%). A low dissipation factor (tan δ) was obtained (~ 0.2) for the optimized loadings of AT and h-BN. Thermal stability of the blends was studied, and a delay in the degradation process at various steps was studied for AT/h-BN-incorporated PVDF/PMMA blends. The overall results suggest that the optimized loading of AT and h-BN significantly improved the dielectric and thermal properties of the PVDF/PMMA blends.

Enhancing combustion performance of nano-Al/PVDF composites with β-PVDF

Solid energetic nanocomposites, consisting of reactive metal particles and oxidizers, find broad applications ranging from pyrotechnics to solid rocket propellants and solid ramjet fuels. In particular, nano-aluminum (n-Al) and polyvinylidene fluoride (PVDF) are attractive fuel and oxidizer materials, due to the high energy density of n-Al, and the high oxidizing potential and excellent mechanical properties of PVDF. PVDF is a semi-crystalline polymer and has three common crystalline phases, alpha (α), gamma (γ), and beta (β) phases. Many research works have focused on the chemical reactions between Al and PVDF, yet the effect of PVDF crystallinity on the Al/PVDF reaction is unknown. Here, we experimentally and computationally demonstrate that increasing the mass fraction of β-phase PVDF from 2.5 to 25% in Al/PVDF composites substantially improves peak pressure by 90% (from ~34 to ~64 psi) and pressure rise rates by 300% (from 2.5 psi/ms to 10 psi/ms). This stems from the alignment of F atoms along one side of the β-PVDF polymer chain, making it structurally conducive to reacting with Al particles to form strong Al-F interactions. This strong interaction leads to higher binding energy between, and hence higher reactivity in, β-PVDF and Al. Our research provides a new method for enhancing the reactive performance of Al/PVDF composites by increasing the content of β-PVDF.

Improving nanoparticle dispersion and polymer crystallinity in polyvinylidene fluoride/POSS coatings using tetrahydrofuran as co-solvent

Dispersion quality of nanoparticles has always limited the performance of polymer nanocomposites and coatings. Herein, the main purpose is to improve the dispersion quality of nanoparticles and overall properties in polyvinylidene fluoride (PVDF)/polyhedral oligomeric silsesquioxane (POSS) nanocomposites fabricated through spray-coating technique. POSS was added to PVDF/DMF solution at varying concentrations. Based on morphological analysis, low to moderate contents (1 and 3 wt%) of POSS exhibited a good dispersion quality but the high contents (5 and 10 wt%) of POSS led to the formation of large aggregates. To improve the dispersion quality of POSS, tetrahydrofuran (THF) was used as co-solvent. The improved dispersion of POSS caused a significant enhancement in the crystallinity of PVDF from 29.8–59.5% according to the differential scanning calorimetry (DSC) results. X-ray diffraction results revealed that the majority of PVDF crystals from the α-type and addition of co-solvent led to the formation of a slight amount of γ phase which was confirmed by the multiple endotherms based on DSC results. The co-solvent addition also led to higher hydrophobicity due to the increased crystallinity. Overall, the use of a proper co-solvent led to better dispersion of nanoparticles which can result in improved performance of nanocomposite coatings.

Mechanical robustness of composite electrode for lithium ion battery: Insight into entanglement & crystallinity of polymeric binder

To investigate the correlation between the molecular weight of the polymeric binder in Li-ion battery electrodes and their adhesion properties, polyvinylidene fluoride (PVdF) with three different molecular weights of 500,000, 630,000, and 1,000,000 are selected for LiCoO2 electrode fabrication. Using a surface and interfacial cutting analysis system, it is observed that, as the molecular weight of the PVdF increases, the adhesion strength not only in the electrode composite, but also at the electrode/current collector interface increases. This enhancement can be attributed to the increased polymeric chain entanglement and higher crystallinity of PVdF with higher molecular weight, which is confirmed using a microfluidic viscometer and differential scanning calorimeter, respectively. In summary, regardless of slightly higher electrode resistance, the LiCoO2 electrode with a PVdF binder of high molecular weight shows better electrochemical performance during cycling test even at 60 °C due to its stable mechanical integrity.

Effect of stimuli-responsive polydiacetylene on the crystallization and mechanical properties of PVDF nanofibers

To improve the β-phase content of polyvinylidene fluoride (PVDF), diacetylene (DA) monomers were embedded in PVDF nanofibers. The PVDF/DA nanofiber membranes were fabricated using the electrospinning technique and polymerized to form polydiacetylene (PDA) after UV irradiation. In this study, the effect of PDA on the crystalline structure of PVDF nanofibers was examined and compared with cast films. The nanofiber morphology was assessed by SEM, while Fourier transform infrared spectroscopy and wide-angle X-ray diffraction were performed to characterize the crystallinity behavior. The mechanical properties and crystal polymorphism of the electrospun PVDF/DA nanofibers were also studied before irradiation, after irradiation and after colorimetric transition induced by the heat treatment. The results showed that the addition of PDA can effectively improve β-phase crystalline PVDF in both the as-cast film and the electrospun nanofibers which is greater in the latter. The electrospun PVDF/DA nanofibers after UV irradiation exhibit greater intensity of β-phase in comparison with those before irradiation. Furthermore, the fraction of β-phase decreased when the blue phase of the PVDF–PDA nanofibers undergoes a heat-induced thermochromic transition to a red phase. The tensile strength and elongation at break as well as the tensile modulus were notably improved after heat treatment of the electrospun PVDF–PDA nanofibers.

Effect of Sulfonation Degree and PVDF Content on the Structure and Transport Properties of SPEEK/PVDF Blend Membranes.

Sulfonated poly (ether ether ketone) (SPEEK) with four different sulfonation degrees (SDs) were prepared, and mixed with polyvinylidene fluoride (PVDF) to prepare four series of SPEEK/PVDF blend membranes. The miscibility between SPEEK and PVDF was investigated by observing the micro-morphologies. The miscible blend membranes were found in the SPEEK/PVDF blend membranes in which either SPEEK had relatively low SD or consisted of low content of one component (either SPEEK or PVDF). The PVDF crystallinity was found to decrease in the SPEEK/PVDF membranes that had better blend miscibility. With the increase of PVDF content, all the blend membranes exhibited the decreased proton conductivity and methanol permeability, and the miscible blend membranes decreased more slowly than the immiscible ones.

Laser induced periodic surface structures on nano metal oxide filled polyvinylidene fluoride nanocomposites

The ability of polarized pulsed laser in surface modification of substrate surfaces without thermally destroying them is a well-established concept of scientific procedure. In this work, we report the laser induced surface structures that are created on the semi crystalline polyvinylidene fluoride (PVDF) polymer and its composites containing transition metal oxides-zinc oxide of 100 nm and iron oxide of 30 nm diameter. The PVDF nanocomposites are fabricated by solution casting method and films of 0.2 mm thickness are used for laser treatment. The periodic structures formed are demonstrated by atomic force microscopy and profilometry investigations. Influence of laser pulses on the material properties is also addressed by means of Fourier transform infrared spectroscopy, contact angle measurements and thermogravimetric/differential scanning calorimetric studies.

Effect of dope solution temperature on the membrane structure and membrane distillation performance

Membrane distillation (MD) is a non-isothermal process applicable to purify water using hydrophobic membrane. Membrane in MD is hydrophobic, permeable to water vapor but repels liquid water. MD membrane is expected to pose high flux, high fouling and scaling resistances and most importantly high wetting resistance. This study develops flat-sheet polyvinylidene fluoride (PVDF) membrane by exploring both liquid-liquid and liquid-solid phase inversion technique largely to improve its wetting resistance and flux performance. We hypothesize that temperature of dope solution play roles in solid-liquid separation during membrane formation and an optimum balance between liquid-liquid and liquid-solid (crystallization) separation leads to highly performance PVDF membrane. Findings obtained from differential scanning calorimeter test show that increasing dope solution temperature reduces degree of PVDF crystallinity and suppresses formation of crystalline structure. The morphological images of the resulting membranes show that at elevated dope solution temperature (40, 60, 80 and 100°C), the spherulite-like structures are formed across the thickness of membranes ascribed from due to different type of crystals. The performance of direct-contact MD shows that the obtained flux of the optimum dope temperature (60°C) of 10.8 L/m2h is comparable to commercial PTFE-based MD membrane.