PVDF Copolymer Research Articles

Use of graphene (go and rGO) as a reinforcement filler to increase the beta phase in fluorinated copolymer nanocomposites

The present study aims to evaluate the influence of different types of graphene, graphene oxide (GO, synthesized by the Hummers method) and reduced graphene oxide (rGO, obtained by thermal reduction of GO) on the piezoelectric properties of composites based on PVDF copolymer. Hydrogen-fluorine interaction is expected to occur between GO or rGO and the fluorinated copolymer, increasing the β-conformation content in the polymer. The samples were prepared in the molten state at two concentrations of each charge inside a twin-screw extruder with interpenetrating screws. The characterizations of the nanocomposites were made according to their thermal and electrical properties. The effect of graphene incorporation into the P(VDF-TrFE) matrix was observed from thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results obtained indicated that the incorporation of graphene contributed to the increase in the β phase content of P(VDF-TrFE), which is indicative of the increase in its piezoelectricity.

Role of Annealing with Electric Field Toward Improvement of Ferroelectric and Electroactive Properties of PVDF Copolymer and Terpolymer Thin Films.

The present study elucidates the role of annealing with electric field on lamellar crystalline structure and molecular orientation of polymer chains in ferroelectric copolymer (P(VDF-TrFE)) and ferroelectric terpolymer (P(VDF-TrFE-CFE)) spin-coated thin films. The ferroelectric polymer thin films annealed under an electric field support the growth of nanostructure with an "edge-on" lamellar crystalline structure having in-plane molecular chain orientation. The poled P(VDF-TrFE) thin films have higher remnant polarization (Pr) ≈6.2µCcm-2 and saturation polarization (Ps) ≈8.2µCcm-2 at an applied electric field of 250 MV/m compared to unpoled thin films having Pr ≈4.7 and Ps ≈6.2µCcm-2. Also, poled P(VDF-TrFE) thin films show lower coercive field (Ec) ≈94 MV/m compared to an unpoled thin film having Ec ≈105 MV/m. Similarly, poled PVDF-TrFE-CFE thin film shows better ferroelectric properties having Pr ≈0.4 and Ps ≈5.7µCcm-2 at an applied electric field of 200 MVm-1 compared to unpoled thin films having Pr ≈0.4 and Ps ≈4.1µCcm-2. The storage energy efficiency of unpoled and poled P(VDF-TrFE-CFE) thin films is measured to be ≈75% and 80%. Annealing of ferroelectric P(VDF-TrFE) polymer thin films under an electric field demonstrates improved ferroelectric and electroactive properties.

Enhancing piezoelectric properties of PVDF-HFP composite nanofibers with cellulose nanocrystals

With the increasing interest in flexible self-powering energy devices, piezoelectric polymers such as poly(vinylidene fluoride) (PVDF), PVDF-trifluoroethylene (PVDF-TrFE and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) have garnered substantial research attention. Among these, PVDF-HFP has demonstrated immense research potential in harvesting mechanical energy and converting it to electric energy. It is also particularly attractive due to its low cost compared to some other PVDF co-polymers. In this study, PVDF-HFP nanofibers were produced by electrospinning with cellulose nanocrystal (CNC) employed as a filler to improve their piezoelectric performance. Smooth and bead-free fibers were obtained with up to 1 wt% of CNC in the solution. The inclusion of CNC increased the uniformity of fiber diameter and improved thermal stability. Higher CNC concentration (2–3 wt%) engendered agglomeration and adversely impacted the conversion of non-polar phase to electroactive phase for PVDF-HFP molecules. At the optimal CNC concentration of 1 wt%, the voltage and current sensitivities for 1 cm2 samples were obtained as 0.146±0.048 mV/mN and 0.009±0.003 nA/mN, respectively. The open-circuit voltage output of 2.69±1.11 V was achieved under an average impact force of 40 N, and this increased with increased magnitude and frequency of the applied force. The mechanical properties of composite nanofibers maximized at 0.5 wt% CNC with tensile strength of 37.85±4.35 MPa, elastic modulus of 124.96±42.17 MPa, and strain at failure of 82.32±14.84 %. The improved piezoelectric and mechanical properties of the CNC-aided electrospun PVDF-HFP fibers will open new pathways for flexible energy harvesting systems.

Enhancing filtration flux and antifouling performance of PVDF membrane constructed from semi-interpenetrating network and block copolymers

Organic fouling causes the filtration property and serve life decrease of the PVDF membrane and is the challenge for filtration applications. Therefore, it is an urgency desire to construct a PVDF membrane with good filtration and antifouling for researchers. To this end, a based PVDF and poly(N-isopropyl acrylamide)(PNIPA) semi-interpenetrating network polymer was synthesized and used as membrane matrix for preparing semi-interpenetrating network/block copolymers blend membrane. The membrane composition, structure and performance were systematically characterized and investigated by FTIR spectrum, XPS, SEM, contact angle instrument and the other experimental techniques etc. Results indicate that the prepared membrane contains PVDF, PNIPA and block copolymer poly(ethylene oxide)-b-poly(propylene oxide)-b- poly(ethylene oxide) (F127) components, shows a porous cross section comprising a thin top surface layer with small pores, a finger-shape lower layer and a sponge-shape pore bottom layer. When the membrane are used for the filtration of bovine serum albumin(BSA) in aqueous solution at 25 ℃, the rejection can exceed 95.0% at a high flux of 307 L/(m2·h·bar). Simply raising filtration temperature to 60 °C, the flux can reach 606 L/(m2·h·bar) while the rejection barely changes, significantly improving the filtration ability of the membrane. Furthermore, the flux can recover above 93% of the original value after a BSA filtration and a subsequent water washing. Undoubtedly, the prepared membrane displays great potential for filtering BSA aqueous solution and the reason can be ascribed to the synergy between PNIPA and F127 of the membrane.

Optical properties of PVDF-TrFE and PVDF-TrFE-CTFE films in terahertz band

Polymers have enormous potential in the optoelectronic and biomedical fields due to flexibility, biocompatibility, and ease of fabrication. Recent developments in the use of terahertz (THz) waves for biomedical and security applications demand information on the optical properties of the polymers and polymer composites in this region. In the present work, transmission, refractive index (n), and extinction coefficient (k) of PVDF-TrFE (75/25 mol.) copolymer and PVDF-TrFE-CTFE (73/23/4 mol.) terpolymer films with different thicknesses (40 μm, 60 μm, 80 μm) are measured by the THz-TDS system (up to 1 THz). PVDF copolymer and terpolymer films show average transmission of more than 90% irrespective of thickness. The average refractive index of PVDF-TrFE (75/25 mol.) copolymer and PVDF-TrFE-CTFE (73/23/4 mol.) terpolymer films are 1.50 ± 0.04 and 1.45 ± 0.05 respectively. The estimated extinction coefficient is considerably low for both polymer films for frequencies less than 0.6 THz. The average indices for PVDF-TrFE and PVDF-TrFE-CTFE films are close, however, the loss in PVDF-TrFE films is larger than the PVDF-TrFE-CTFE films. High transmission, low loss and ferroelectric properties make these PVDF based polymers highly desirable in light-wave manipulation, flexible electronic and solar devices.

The effect of sulfonated copolymer as a binder on the electrochemical performance of LiFePO4 cathode for lithium-ion batteries

In today's market, lithium-ion batteries are proving to be the most promising and effective rechargeable batteries. In the development of active materials with high energy density for batteries, the design of binders is a bottleneck technology, which produces an interconnected electrode structure. In this study, for developing lithium-ion batteries with high efficiency, the sulfonated copolymer was employed as an effective binder. In order to improve the performance of poly(vinylidene fluoride) (PVDF) as a binder for lithium-ion batteries (LIBs), sulfonated PVDF copolymer was prepared in this study using the atom transfer radical polymerization (ATRP) process. The influence of sulfonated PVDF binder on the electrochemical performances of LIBs was assessed using charge and discharge measurements, cycling performance up to 300 cycles, cycling voltammetry (CV), and electrochemical impedance spectroscopy (EIS) analysis. The investigation indicated decreased concentration polarization and improved lithiation and delithiation kinetics at high number of charge/discharge cycles for LiFePO4 electrodes with sulfonated PVDF binders. The discharge capacity after 300 cycles was 90 mAh g−1 with a capacity retention of 100% at 1C. As a result, the copolymer synthesized in this paper can be utilized to design next-generation polymer binders for high-efficiency LIBs.

(PVDF)2(PEO)2 miktoarm star copolymers: Synthesis and isothermal crystallization leading to exclusive β-phase formation

In this work, we study how chain topology can induce different polymorphic behaviors in poly(vinylidene fluoride) (PVDF)-based materials. A linear PVDF precursor with two azido groups at the junction point, (PVDFx-N3)2 and three 4-miktoarm star copolymers (PVDFx)2-b-(PEOy)2 with two poly(ethylene oxide) (PEO) and two PVDF arms were synthesized and employed in this study. The amphiphilic miktoarm copolymers were prepared by a combination of anionic ring-opening polymerization, iodine transfer radical polymerization (ITP), and copper-catalyzed azide-alkyne cycloaddition (CuAAC). They have practically similar overall molar mass but different compositions, ideal for performing bulk morphology and crystallization investigations. The isothermal overall crystallization kinetics of the PVDF and PEO arms of the 4-miktoarm star copolymers and representative PEO and PVDF precursors was determined by Differential Scanning Calorimetry (DSC). The results indicate that the star arms crystallized faster than the equivalent precursors as the kinetics are dominated by nucleation effects. The phases formed by the PVDF components in the materials examined were analyzed by studying their melting behavior by DSC, their superstructural morphology by Polarized Light Optical Microscopy (PLOM), and the phase structure by Fourier Transform Infrared Spectroscopy (FTIR). The linear PVDF and (PVDF29-N3)2, exhibited α, β and γ-phases (with a majority of β-phase formation) during melting after isothermal crystallization. The ratio of the different phases depends on the crystallization temperature. An analysis of the multiple melting behavior indicated that the sample forms both α and β-phases initially, and the α-phase partially transforms into the γ-phase during isothermal crystallization when the temperature of crystallization increases. We found a remarkable behavior for the 4-miktoarm star copolymers, as the PVDF arms only form the ferroelectric β-phase when all three materials were isothermally crystallized regardless of the crystallization temperature employed. The presence of the polymorphism in the PVDF was detected by DSC, PLOM, and FTIR. Hence, we have shown that tailoring chain topology in PVDF copolymers can lead to exclusive β-phase formation, a path that can be exploited for future piezoelectric applications.

Flexible and high dielectric permittivity composites of Na1/3Ca1/3Bi1/3Cu3Ti4O12 and vinylidene fluoride‐trifluoroethylene copolymer (P[VDF‐co‐TrFE

AbstractFlexible composites formed by the perovskite Na1/3Ca1/3Bi1/3Cu3Ti4O12 (NCBCTO) with a copolymer of PVDF with TrFE (P[VDF‐co‐TrFE]) and three phases composites made of NCBCTO, P(VDF‐co‐TrFE), and multiwall carbon nanotubes (MWCNT) were successfully prepared by solution casting with ultrasound. Their structures were analyzed by wide angle x‐rays diffraction (XRD), Fourier Transform infrared (FTIR), and Raman spectroscopy, while their morphology and thermal properties were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. The dielectric properties were measured by impedance spectroscopy. All the composites developed predominantly the β‐phase; in some of them, the NCBCTO acted as a β‐phase nucleating agent, increasing its amount. The addition of NCBCTO altered the Curie temperature of the PVDF‐TrFe composites, indicating suppression of the CL‐phase. The best combination of high dielectric permittivity with low dielectric loss was displayed by the composite with 75 wt% of NCBCTO and 25 wt% of P(VDF‐co‐TrFE). The MWCNTs did not contribute to the increase of permittivity, which was attributed to its poor dispersion; instead of behaving as the electrodes of a capacitor, the MWCNT formed a conductive path, probably due to the impeding presence of the NCBCTO particles.

3D printing of polyvinylidene fluoride composite films with enhanced electroactive beta-phase for flexible wearable pressure sensors

Following the notable rise of three-dimensional (3D) printing in recent years, its use for the fabrication of functional devices derived from piezoelectric polymers such as poly (vinylidene fluoride), PVDF, has become an active area of research. However, there is still a lot to understand about the structure–property-processing relationship regarding the 3D printing of PVDF-based polymers with an enhanced piezoelectric property, which is closely related to the β-phase crystal structure of the polymer. This paper presents the preliminary results of investigations into the extrusion-based 3D printing of poly(vinylidene fluoride-hexafluoropropylene), PVDF-HFP, a PVDF copolymer. Towards the enhancement of the β-phase content of this copolymer, the study analyzed the influence of two fillers in the form of barium titanate (BaTiO3) and untreated activated carbon (UAC) and considered the effect of two printing parameters on the piezoelectric crystalline structure of the PVDF-HFP. First, composite films of the PVDF-HFP with the fillers were formed via the solvent evaporation casting method. From the characterization of the solvent-cast samples using Fourier Transform Infrared Spectrum (FTIR), a composite consisting of 10.55 wt% BaTiO3 and 0.45 wt% UAC with the matrix of PVDF-HFP was found to produce a superior β-phase content (67%) and it was deployed for syringe-based extrusion-assisted 3D printing. Post-fabrication characterization of the extruded samples was carried out to examine the influence of the 3D printing conditions in the form of printing bed temperature (50, 75, 95) and extrusion speed (10, 15, 25). It was found that the combination of a higher printing bed temperature and a low printing speed further enhanced the β-phase content for the PVDF-HFP composites, yielding a β-phase content of 79.6%. Confirmation of the electromechanical/piezoelectric response of the unpoled strips of printed samples revealed a positive correlation between the externally applied pressure on the printed strips and generated voltage.

Integrated analysis of chain orientation induced anisotropy in nanoimprinted PVDF based copolymers

Poly(vinylidene fluoride) (PVDF) and its copolymers are electrically active materials that have the ability to harvest mechanical energy through mechanical vibrations and structural flexing. Due to the inherent nanoscale dependency of the molecular structure of PVDF copolymer, efficient methods for investigating the effects of chain orientation on its localized nanomechanical properties are very limited. In this manuscript, we use infrared atomic force microscope (IR-AFM), contact-resonance atomic force microscopy (CR-AFM), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (TEM), to reveal the correlations between localized molecular vibration, anisotropy, and the corresponding dynamic nanomechanical properties. IR-AFM is able to probe the chain orientation of the PVDF copolymer and CR-AFM is able to resolve the in-plane anisotropy along the axis of the polymer chain. The combination of these techniques can provide a quick, effective, nondestructive method to reveal the formation mechanisms, which could lead to optimization of the electroactive polymer organization.

Advancements in Sustainable PVDF Copolymer Membrane Preparation Using Rhodiasolv® PolarClean As an Alternative Eco-Friendly Solvent

In this work, Rhodiasolv® PolarClean was employed as a more sustainable solvent for the preparation of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) flat sheet membranes via phase inversion technique by coupling vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) processes. Preliminary calculations based on Hansen solubility parameters well predicted the solubilization of the polymer in the selected solvent. The effect of exposure time on humidity and the influence of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and sulfonated polyether sulfone (S-PES) on membrane properties and performance, were evaluated. Three different coagulation bath compositions were also explored. The obtained membranes, prepared using a more sustainable approach, were compared with those produced with the traditional toxic solvent N-methyl-2-pyrrolidone (NMP) and characterised in terms of morphology, porosity, wettability, pore size, surface roughness and mechanical resistance. The potential influence of the new solvent on the crystallinity of PVDF-HFP-based membranes was also evaluated by infrared spectroscopy. The adjustment of the parameters investigated allowed tuning of the membrane pore size in the microfiltration (MF) and ultrafiltration (UF) range resulting in membranes with various morphologies. From the water permeability and rejection tests, performed with methylene blue dye, the prepared membranes showed their potentiality to be used in MF and UF applications.

Thermal degradation behavior of ionic liquid/ fluorinated polymer composites: Effect of polymer type and ionic liquid anion and cation

This work reports on the evaluation of the thermal degradation of poly(vinylidene fluoride) (PVDF) and PVDF co-polymer (PVDF-TrFE, PVDF-HFP and PVDF-CTFE) composite films with different imidazolium ionic liquids (ILs). The influence of the IL type, including cation and anion type, cation chain length and content up to 40 wt% were evaluated. Independently of the fluorinated polymer type, all neat samples present a single degradation step. Upon the incorporation of the IL [C2mim][TFSI] into the different polymers, a decrease in the thermal stability occurs, indicating the IL imidazolium interaction with the CH2-CF2 groups of the fluorinated matrix. Further, it was stablished that the thermal stability of the composite material decreases with increasing cation chain length. The Ozawa-Flynn-Wall and Kissinger models were applied to evaluate the activation energies of the samples during isothermal experiments, showing that the thermal degradation activation energy ranges from 161 ± 6 kJ mol−1 ([C2mim][TFSI]/PVDF) to 131 ± 14 kJ mol−1 ([C2mim][TFSI]/PVDF-CTFE). No large differences were observed on the effect of IL inclusion in PVDF, PVDF-TrFE, PVDF-HFP and PVDF-CTFE polymer matrices.

Ultrastretchable conductive liquid metal composites enabled by adaptive interfacial polarization.

Gallium-based liquid metals (LMs) are emerging candidates for the development of metal/polymer-based flexible circuits in wearable electronics. However, the high surface energies of LMs make them easily depleted from the polymer matrix and therefore substantially suppress the stretchability of the conductive composites. Here, we reveal that a dynamic interplay between the LM and the polyvinylidene fluoride (PVDF) copolymer can help to address these issues. Weak and abundant interfacial polarization interactions between the PVDF copolymer and the oxide layer allow continuous and adaptive configuration of the compartmented LM channels, enabling ultra-stretchability of the composites. The conductive LM-polymer composites can maintain their structural integrity with a high surface conductivity and small resistance changes under large strains from 1000% to 10 000%. Taking advantage of their flexible processability under mild conditions and exceptional performance, our design strategy allows the scalable fabrication of conductive LM-polymer composites for a range of applications in wearable devices and sensors.

Evaluation of adhesive-free focused high-frequency PVDF copolymer transducers fabricated on spherical cavities

A layer-by-layer deposition method for fabricating a focused ultrasonic transducer from piezoelectric copolymers has been developed. The fabrication process involves engraving a spherical cavity of 2 mm diameter on polyethyleneimines (PEI) polymer substrate. Surface roughness of the engraved spherical cavity is measured and compared with simulated line scan. Then, the transducer response was investigated by observing the acoustic pulse reflection from the glass plate used as reflector in a focal point. The average central frequency responses were measured to be 48.5 MHz, with a lower and upper −6 dB frequencies of approximately 25 and 76.5 MHz, yielding a bandwidth of 94.2%. A scanning hydrophone system has been employed to determine the focal zone of the transducer and compared with simulation using COMSOL Multiphysics. Two-dimensional surface scanning was performed on the test sample to provide the ultrasonic imaging of the transducer prototype and compare the image with commercial PVDF transducer with a center frequency of (48.5 ± 1) MHz.

Electromechanical Properties of PVDF-Based Polymers Reinforced with Nanocarbonaceous Fillers for Pressure Sensing Applications.

Polymer-based composites reinforced with nanocarbonaceous materials can be tailored for functional applications. Poly(vinylidene fluoride) (PVDF) reinforced with carbon nanotubes (CNT) or graphene with different filler contents have been developed as potential piezoresistive materials. The mechanical properties of the nanocomposites depend on the PVDF matrix, filler type, and filler content. PVDF 6010 is a relatively more ductile material, whereas PVDF-HFP (hexafluropropylene) shows larger maximum strain near 300% strain for composites with CNT, 10 times higher than the pristine polymer. This behavior is similar for all composites reinforced with CNT. On the other hand, reduced graphene oxide (rGO)/PVDF composites decrease the maximum strain compared to neat PVDF. It is shown that the use of different PVDF copolymers does not influence the electrical properties of the composites. On the other hand, CNT as filler leads to composites with percolation threshold around 0.5 wt.%, whereas rGO nanocomposites show percolation threshold at ≈ 2 wt.%. Both nanocomposites present excellent linearity between applied pressure and resistance variation, with pressure sensibility (PS) decreasing with applied pressure, from PS ≈ 1.1 to 0.2 MPa−1. A proof of concept demonstration is presented, showing the suitability of the materials for industrial pressure sensing applications.

Does the nature of chemically grafted polymer onto PVDF decide the extent of electroactive β-polymorph?

PVDF, one of the most versatile fluoropolymers, is inert and is difficult to functionalize using conventional approaches. Herein, we attempted a facile and one-pot modification of PVDF via ozonization process. The ozone treated PVDF facilitates in harnessing suitable functional moieties. Using this strategy, two copolymers were designed to achieve crystalline-amorphous and crystalline-crystalline grafts. Their effects on phase transformation, dielectric and piezoelectric behaviors of PVDF were systematically investigated. The microstructure and phase transformation of this modified PVDF copolymer was characterized by XPS, XRD, FTIR, SAXS, and DSC. FTIR results revealed that the extent of polar β phase increased from 38% in untreated PVDF to 84% after ozonization. Interestingly, the enhancement is more pronounced after grafting. For instance, after grafting a crystalline polymer, poly (butylene succinate-co-adipate) (PBSA) onto PVDF near-complete transformation from α to β phase (96%) was observed. This was attributed to the specific covalent interaction between the –OH group in PVDF-OH and –COOH groups of PBSA. This strong covalent interaction helps to align the PVDF chains in trans conformation and as a result more β phase crystals are formed. The long period (Lw) calculated from SAXS for an amorphous graft as in PVDF-g-poly(methyl methacrylate-co-acrylic acid) (PMM-co-AA) and PVDF-g-PBSA decreased significantly as compared to neat PVDF. The remarkably enhanced β phase in the grafted polymers reflected in higher dielectric constant and piezoelectric coefficient (d33) as compared to untreated PVDF. For instance, the PVDF-g-PBSA copolymer showed higher piezoelectric and dielectric constant with low dielectric loss as compared to untreated PVDF. This study attempts to address whether the nature of graft (crystalline vs amorphous) decides the extent of β-PVDF and piezoelectric properties in PVDF copolymers.

Surface wettability modification of poly(vinylidene fluoride) and copolymer films and membranes by plasma treatment

This manuscript reports on the modification of the surface wettability of poly (vinylidene fluoride) (PVDF) and PVDF copolymer films and membranes by plasma treatments at different conditions, under oxygen and argon atmospheres. It is shown that a more pronounced decrease of the contact angle after O2 plasma treatments is obtained, with a decrease of ∼20-30° for PVDF and its copolymers films, leading also to superhydrophilic membranes. This effect is related to a defluorination process, followed by the incorporation of oxygen atoms onto the surface of membranes that occurs during the surface modification. The influence of plasma treatments on surface morphology and topography was studied by atomic force microscopy, showing a decrease in the mean surface roughness with the plasma treatments, being more noticeable for Ar treatments. Finally, it is also shown that plasma treatments under Ar and O2 did not induce modifications in the physicochemical and thermal properties of PVDF and PVDF copolymers. The chemical reaction mechanism after plasma treatment is proposed for the different copolymers.

Nano-porous shape memory membrane: Fabrication based on double bicontinuous structures in ternary blend and pore-size manipulation by macroscopic deformation

Nano-pore size is the key factor to determine the performance of porous membrane in various applications. The programmable and continuous manipulation of it remains as a great challenge. In this work, nano-porous shape memory polymer (SMP) membrane has been fabricated successfully in ternary blend of PVDF, PBSU and random copolymer (BMG) based on the special interface interaction and complicated phase behaviors among them. On one hand, phase separation takes place, producing bicontinuous structures with the characteristic size of microns including BMG rich phase and PVDF/PBSU mixed phase. The former provides shape memory effect in which cross-linked points and network play the roles of shape fixed phase and recovery phase respectively; on the other hand, exclusion of PBSU during crystallization of PVDF contributes to bicontinuous structures in nanoscale. The removal of PBSU based on double bicontinuous structures results in the interconnected nano-pores. The obtained nano-porous PVDF/BMG composite membranes possess not only shape memory performance, but also the interpenetrated channels. The pore size has been manipulated successfully by means of biaxial tension based on the proportional deformation in macro- and micro-scales. Our results provide a new strategy for the fabrication of nano-porous SMPs and the manipulation of pore size in them.

2E1-5 Adhesive free PVDF copolymer focused transducers for high frequency acoustic imaging

2E1-5 Adhesive free PVDF copolymer focused transducers for high frequency acoustic imaging

Novel anti-fouling PVDF-g-THFMA copolymer membrane fabricated via photoinduced Cu(II)-mediated reversible deactivation radical polymerization

In this study, we fabricated a novel anti-fouling poly(vinylidene fluoride) (PVDF) membrane using a novel amphiphilic copolymer of PVDF grafted with tetrahydrofurfuryl methacrylate (PVDF-g-THFMA). This copolymer was synthesized via photoinduced Cu(II)-mediated reversible deactivation radical polymerization. The amphiphilic copolymer was characterized by 1H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The morphology of the copolymer was examined using scanning electron microscopy. The permeability and hydrophilicity of the membranes were evaluated on the basis of their pure water flux and dynamic contact angles, respectively. The anti-fouling property of the membranes was evaluated by carrying out filtration using a bovine serum albumin (BSA) solution. The PVDF-g-THFMA copolymer membranes showed a pure flux of up to 293.9 L m−2 h−1 bar−1 and a molecular weight cut off of 39.5 kDa. After the filtration of the BSA solution, the PVDF-g-THFMA copolymer membrane was washed with deionized water and the recovery ratio of the pure water flux reached a value of 89.1%. The modified membrane showed good filtration performance and anti-fouling property.