Browse
Submit Data
Databases
API
Help

Dataset Information

30 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Nanoconfinement-Induced β-Phase Formation Inside Poly(vinylidene fluoride)-Based Block Copolymers.

ABSTRACT: The electroactive properties of poly(vinylidene fluoride) (PVDF) are a direct consequence of its crystalline phases. Although poorly understood, nanostructuring PVDF in confined geometries can drastically change its crystallization behavior. Therefore, we synthesized a variety of PVDF-based triblock copolymers to gain a better understanding of the melt crystallization and explore how crystallization is affected by the morphology and chemical nature of the amorphous block. Differential scanning calorimetry, small-/wide-angle X-ray scattering, and transmission electron microscopy gave us excellent insights into the morphology and the corresponding crystalline phases. We find that crystallization of PVDF inside spherical nanodomains occurs via a homogeneous nucleation mechanism leading to a large undercooling and the formation of the thermodynamically favorable ferroelectric β-phase. On the contrary, when confined crystallization occurs inside a lamellar morphology, or in the case of breakout crystallization, a heterogeneous nucleation process leads to the formation of the nonferroelectric α-phase. Furthermore, favorable melt interactions between both blocks induce crystallization into the polar γ-phase at moderate cooling rates.

SUBMITTER: Meereboer NL

PROVIDER: S-EPMC6052937 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Inducing β Phase Crystallinity in Block Copolymers of Vinylidene Fluoride with Methyl Methacrylate or Styrene.

Project description:Block copolymers of poly(vinylidene fluoride) (PVDF) with either styrene or methyl methacrylate (MMA) were synthesized and analyzed with respect to the type of the crystalline phase occurring. PVDF with iodine end groups (PVDF-I) was prepared by iodine transfer polymerization either in solution with supercritical CO₂ or in emulsion. To activate all iodine end groups Mn₂(CO)10 is employed. Upon UV irradiation Mn(CO)₅ radicals are obtained, which abstract iodine from PVDF-I generating PVDF radicals. Subsequent polymerization with styrene or methyl methacrylate (MMA) yields block copolymers. Size exclusion chromatography and NMR results prove that the entire PVDF-I is converted. XRD, FT-IR, and differential scanning calorimetry (DSC) analyses allow for the identification of crystal phase transformation. It is clearly shown that the original α crystalline phase of PVDF-I is changed to the β crystalline phase in case of the block copolymers. For ratios of the VDF block length to the MMA block length ranging from 1.4 to 5 only β phase material was detected.

| S-EPMC6418974 | biostudies-literature

Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends.

Project description:The crystallization and morphology of two linear diblock copolymers based on polymethylene (PM) and poly(vinylidene fluoride) (PVDF) with compositions PM23-b-PVDF77 and PM38-b-PVDF62 (where the subscripts indicate the relative compositions in wt%) were compared with blends of neat components with identical compositions. The samples were studied by SAXS (Small Angle X-ray Scattering), WAXS (Wide Angle X-ray Scattering), PLOM (Polarized Light Optical Microscopy), TEM (Transmission Electron Microscopy), DSC (Differential Scanning Calorimetry), BDS (broadband dielectric spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). The results showed that the blends are immiscible, while the diblock copolymers are miscible in the melt state (or very weakly segregated). The PVDF component crystallization was studied in detail. It was found that the polymorphic structure of PVDF was a strong function of its environment. The number of polymorphs and their amount depended on whether it was on its own as a homopolymer, as a block component in the diblock copolymers or as an immiscible phase in the blends. The cooling rate in non-isothermal crystallization or the crystallization temperature in isothermal tests also induced different polymorphic compositions in the PVDF crystals. As a result, we were able to produce samples with exclusive ferroelectric phases at specific preparation conditions, while others with mixtures of paraelectric and ferroelectric phases.

| S-EPMC8348057 | biostudies-literature

Ultrahigh β-phase content poly(vinylidene fluoride) with relaxor-like ferroelectricity for high energy density capacitors.

Project description:Poly(vinylidene fluoride)-based dielectric materials are prospective candidates for high power density electric storage applications because of their ferroelectric nature, high dielectric breakdown strength and superior processability. However, obtaining a polar phase with relaxor-like behavior in poly(vinylidene fluoride), as required for high energy storage density, is a major challenge. To date, this has been achieved using complex and expensive synthesis of copolymers and terpolymers or via irradiation with high-energy electron-beam or γ-ray radiations. Herein, a facile process of pressing-and-folding is proposed to produce β-poly(vinylidene fluoride) (β-phase content: ~98%) with relaxor-like behavior observed in poly(vinylidene fluoride) with high molecular weight > 534 kg mol-1, without the need of any hazardous gases, solvents, electrical or chemical treatments. An ultra-high energy density (35 J cm-3) with a high efficiency (74%) is achieved in a pressed-and-folded poly(vinylidene fluoride) (670-700 kg mol-1), which is higher than that of other reported polymer-based dielectric capacitors to the best of our knowledge.

| S-EPMC6800420 | biostudies-literature

Quaternized Amphiphilic Block Copolymers/Graphene Oxide and a Poly(vinyl alcohol) Coating Layer on Graphene Oxide/Poly(vinylidene fluoride) Electrospun Nanofibers for Superhydrophilic and Antibacterial Properties.

Project description:Poly(vinylidene fluoride) (PVDF) is common polymer for electrospinning, however, its high hydrophobicity is a major drawback, which cause fouling. To introduce hydrophilicity and antibacterial activity, quaternary ammonium-functionalized amphiphilic diblock copolymers were synthesized and blended with a PVDF/graphene oxide (GO) solution, then, electrospun and coated with a hydrophilic polymer, poly(vinyl alcohol) (PVA). The amphiphilic block copolymer, consisting of a hydrophobic poly(methyl methacrylate) block and a hydrophilic poly[N,N-2-(dimethylamino)-ethyl methacrylate) block (PMMA-b-PDMAEMA), was synthesized. Polymeric quaternary ammonium with three different alkyl chain lengths (C2, C4, and C8) were successfully introduced to obtain as q-PMMA-b-PDMAEMA. The q-PMMA-b-PDMAEMA in the nanofiber matrix was confirmed by C=O bands (1734 cm-1) in the Fourier transform infrared spectra. Nano-sized spherical protuberances were distributed on the surface as revealed by field emission scanning and transmission electron microscopies. The PVDF/GO/q-PMMA-b-PDMAEMA@PVA nanofibers has superhydrophilic properties (water contact angle?=?0-20°) and the pure water flux was generally improved by increasing the alkyl chain length. When introducing the longest alkyl chain (C8,OBC), the total fouling ratio was the lowest (49.99%) and the bacteria removal capacities after 60?min were the highest for both Escherichia coli (4.2?×?105 CFU/mg) and Staphylococcus aureus (6.1?×?105 CFU/mg) via growth inhibition and cytoplasmic membrane damage.

| S-EPMC6344507 | biostudies-literature

Preparation and electroactive phase adjustment of Ag-doped poly(vinylidene fluoride) (PVDF) films.

Project description:The crystallinities of Ag-doped poly(vinylidene fluoride) (PVDF) films were modified by removing Ag+ using a novel washing process, which allowed control of the ratio of γ- and β-phases. The polarity of the composite film without Ag+ removal through the washing process reached 98%, and the β-phase content in the total electroactive phase was increased to 61%, according to Fourier-transform infrared spectroscopy. When Ag+ were removed through a process involving several cycles of washing, filtering, drying, and re-dissolving, the highest ratio of the γ-phase was increased to 67%, 28% higher than that before washing. This showed that Ag+ induced β-phase formation while Ag nanoparticles induced γ-phase formation, and that the ratio of γ- and β-phases in PVDF composite films can be controlled to suit specific applications by this washing process.

| S-EPMC9076169 | biostudies-literature

Crystallization of Poly(ε-caprolactone) in Poly(vinylidene fluoride)/Poly(ε-caprolactone) Blend.

Project description:The crystallization behavior of poly(ε-caprolactone) (PCL) in a poly(vinylidene fluoride) (PVDF)/PCL blend as well as on a highly orientated PVDF substrate was studied by means of POM, DSC and TEM. The results show that the miscibility of the PVDF/PCL blend and the spherulitic morphology of PVDF varies with the blend ratio. For all the compositions, the pre-existing PVDF crystals accelerated the crystallization of PCL because the PVDF exhibits very strong nucleation ability toward PCL as reflected by the occurrence of heteroepitaxy and the transcrystallization of PBA on the PVDF substrate. This is associated with the perfect lattice matching between the PBA and PVDF crystals.

| S-EPMC6432374 | biostudies-literature

Two-Stage Evolution of Gamma-Phase Spherulites of Poly (Vinylidene Fluoride) Induced by Alkylammonium Salt.

Project description:We investigated the evolution of the γ-phase spherulites of poly(vinylidene fluoride) (PVDF) added to 1 wt% of tetrabutylammonium hydrogen sulfate during the isothermal crystallization at 165 °C through polarized optical microscopy and light scattering measurements. Optically isotropic domains grew, and then optical anisotropy started to increase in the domain to yield spherulite. Double peaks were seen in the time variation of the Vv light scattering intensity caused by the density fluctuation and optical anisotropy, and the Hv light scattering intensity caused by the optical anisotropy started to increase during the second increase in the Vv light scattering intensity. These results suggest the two-stage evolution of the γ-phase spherulites, i.e., the disordered domain grows in the first stage and ordering in the spherulite increases due to the increase in the fraction of the lamellar stacks in the spherulite without a change in the spherulite size in the second stage. Owing to the characteristic crystallization behavior, the birefringence in the γ-phase spherulites of the PVDF/TBAHS was much smaller than that in the α-phase spherulites of the neat PVDF.

| S-EPMC9504496 | biostudies-literature

Resistive non-volatile memories fabricated with poly(vinylidene fluoride)/poly(thiophene) blend nanosheets.

Project description:Ferroelectric poly(vinylidene fluoride)/semiconductive polythiophene (P3CPenT) blend monolayers were developed at varying blend ratios using the Langmuir-Blodgett technique. The multilayered blend nanosheets show much improved surface roughness that is more applicable for electronics applications than spin-cast films. Because of the precisely controllable bottom-up construction, semiconductive P3CPenT were well dispersed into the ferroelectric PVDF matrix. Moreover, the ferroelectric matrix contains almost 100% β crystals: a polar crystal phase responsible for the ferroelectricity of PVDF. Both the good dispersion of semiconductive P3CPenT and the outstanding ferroelectricity of the PVDF matrix in the blend nanosheets guaranteed the success of ferroelectric organic non-volatile memories based on ferroelectricity-manipulated resistive switching with a fresh high ON/OFF ratio and long endurance to 30 days.

| S-EPMC9078467 | biostudies-literature

Janus Poly(Vinylidene Fluoride) Membranes with Penetrative Pores for Photothermal Desalination.

Project description:Solar-driven desalination has been considered as a promising technology for producing clean water through an abundant and pollution-free energy source. It is a critical challenge to reasonably design the porous morphology and the thermal management of photothermal membranes for enabling efficient energy conversion and water production. In this work, a Janus poly(vinylidene fluoride) membrane was fabricated in combination of penetrative pore structure, asymmetric surface wettability with proper thermal management for high-efficiency solar desalination. Highly open and directly penetrative pores achieved by the two-dimensional solvent freezing strategy are considered to provide direct pathways for water and vapor transportation. The unique feature of hydrophobic upper layer/hydrophilic lower layer enables the photothermal membranes to self-float on the water surface and rapidly pump water from the bulk to the surface. The resulting Janus membrane exhibits a satisfactory light absorbance as high as 97% and a photothermal conversion efficiency of 62.8% under one-sun irradiation in a direct contact mode. The solar-to-vapor efficiency rises up to 90.2% with the assistance of a thermal insulator adopted beneath. Both the Janus membrane and the composite setup are able to work efficiently with a high stability in seawater desalination, and the concentration of ion in condensed water is reduced to below 1 ppm. Therefore, Janus membranes with directly penetrative pores and photothermal surfaces shine a light on the development of high-performance solar evaporators for the practical application in solar seawater desalination.

| S-EPMC7072121 | biostudies-literature

Flexophotovoltaic Effect in Potassium Sodium Niobate/Poly(Vinylidene Fluoride-Trifluoroethylene) Nanocomposite.

Project description:Flexoelectricity is an electromechanical coupling effect in which electric polarization is generated by a strain gradient. In this investigation, a potassium sodium niobite/poly(vinylidene fluoride-trifluoroethylene) (KNN/PVDF-TrFE)-based nanocomposite is fabricated, and the flexoelectric effect is used to enhance the photovoltaic current (I pv) in the nanocomposite. It is found that both a pyroelectric current and photovoltaic current can be generated simultaneously in a light illumination process. However, the photovoltaic current (I pv) in this process contributes ≈85% of the total current. When assessing the effect of flexoelectricity with a curvature of 1/20, the I pv of the curved KNN/PVDF-TrFE (20%) (K/P-20) composite increased by ≈13.9% compared to that of the flat K/P-20 nanocomposite. Similarly, at a curvature of 1/20, the I pv of the K/P-20 nanocomposite is 71.6% higher than that of the PVDF-TrFE film. However, the photovoltaic effect induced by flexoelectricity is much higher than the increased polarization from flexoelectricity, so this effect is called as the flexophotovoltaic effect. Furthermore, the calculated energy conversion efficiency of the K/P-20 film is 0.017%, which is comparable to the previous research result. This investigation shows great promise for PVDF-based nanocomposites in ferroelectric memory device applications.

| S-EPMC8061384 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data