scholarly journals On fabrication of nanoscale non-smooth fibers with high geometric potential and nanoparticle’s non-linear vibration

2020 ◽  
Vol 24 (4) ◽  
pp. 2491-2497 ◽  
Author(s):  
Xin Yao ◽  
Ji-Huan He
Keyword(s):  
Smooth Surface ◽  
Vinylidene Fluoride ◽  
High Surface ◽  
Solvent System ◽  
Binary Solvent ◽  
Linear Vibration ◽  
Multi Wall Carbon Nanotubes ◽  
Micro Scale ◽  
Poly Vinylidene Fluoride ◽  
High Surface Energy

Non-smooth surface of a nano or micro-scale fiber has an extremely large surface area and a tremendously high surface energy (geometric potential). This paper focuses on the formation mechanism of fabrication of a non-smooth surface by electrospinning through controlling solvent evaporation and nanoscale adhesion of nanoparticles on the surface. Poly(vinylidene fluoride), multi-wall carbon nanotubes and a binary solvent system are adopted in the experiment to elucidate how to fabricate nanoscale porous nanofibers and lotus-surface-like nanofibers. A nanoparticle?s vibration near its equilibrium is also discussed, which also affects greatly the surface morphology.

scholarly journals A Review on Porous Polymeric Membrane Preparation. Part I: Production Techniques with Polysulfone and Poly (Vinylidene Fluoride)

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1160 ◽  
Author(s):  
XueMei Tan ◽  
Denis Rodrigue
Keyword(s):  
Phase Separation ◽  
Vinylidene Fluoride ◽  
Solvent System ◽  
Processing Parameters ◽  
Membrane Preparation ◽  
Polymeric Membrane ◽  
Ambient Conditions ◽  
Membrane Fabrication ◽  
Core Technology ◽  
Poly Vinylidene Fluoride

Porous polymeric membranes have emerged as the core technology in the field of separation. But some challenges remain for several methods used for membrane fabrication, suggesting the need for a critical review of the literature. We present here an overview on porous polymeric membrane preparation and characterization for two commonly used polymers: polysulfone and poly (vinylidene fluoride). Five different methods for membrane fabrication are introduced: non-solvent induced phase separation, vapor-induced phase separation, electrospinning, track etching and sintering. The key factors of each method are discussed, including the solvent and non-solvent system type and composition, the polymer solution composition and concentration, the processing parameters, and the ambient conditions. To evaluate these methods, a brief description on membrane characterization is given related to morphology and performance. One objective of this review is to present the basics for selecting an appropriate method and membrane fabrication systems with appropriate processing conditions to produce membranes with the desired morphology, performance and stability, as well as to select the best methods to determine these properties.

Electrospun Poly(vinylidene fluoride)-based Carbon Nanofibers for Hydrogen Storage

2004 ◽  
Vol 837 ◽  
Author(s):  
H. J. Chung ◽  
D. W. Lee ◽  
S. M. Jo ◽  
D. Y. Kim ◽  
W. S. Lee
Keyword(s):  
Hydrogen Storage ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Storage Capacity ◽  
Vinylidene Fluoride ◽  
High Surface ◽  
Gravimetric Method ◽  
Magnetic Suspension ◽  
Hydrogen Storage Capacity ◽  
Poly Vinylidene Fluoride

ABSTRACTPoly(vinylidene fluoride) (PVdF) fine fiber of 200–300 nm in diameter was prepared through the electrospinning process. Dehydrofluorination of PVdF-based fibers for making infusible fiber was carried out using DBU, and the infusible PVdF-based nanofibers were then carbonized at 900–1800°C. The structural properties and morphologies of the resulting carbon nanofibers were investigated using XRD, Raman IR, SEM, TEM, and surface area & pore analysis. The PVdF-based carbon nanofibers had rough surfaces composed of 20-to 30-nm granular carbons, indicating their high surface area in the range of 400–970 m2/g. They showed amorphous structures. In the case of the highly ehydrofluorinated PVdF fiber, the resulting carbon fiber had a smoother surface, with d002 = 0.34–0.36 nm, and a very low surface area of 16–33 m2/g. The hydrogen storage capacities of the above carbon nano-fibers were measured, using the gravimetric method, by magnetic suspension balance (MSB), at room temperature and at 100 bars. The storage data were obtained after the buoyancy correction. The PVdF-based microporous carbon nanofibers showed a hydrogen storage capacity of 0.04–0.4 wt%. The hydrogen storage capacity depended on the dehydrofluorination of the PVdF nanofiber precursor, and on the carbonization temperatures.

Preparation and characterization of anti-fouling PVDF membrane modified by chitin

2017 ◽  
Vol 37 (3) ◽  
pp. 313-321 ◽  
Author(s):  
Manman Xie ◽  
Xia Feng ◽  
Juncheng Hu ◽  
Zhengyi Liu ◽  
Zijian Wang ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Solvent System ◽  
Pvdf Membrane ◽  
Blend Membrane ◽  
Poly Vinylidene Fluoride ◽  
And Performance ◽  
Membrane Structure And Performance ◽  
Precipitation Phase

Abstract Poly(vinylidene fluoride) (PVDF)/chitin (CH) blend membranes were prepared via the method of immersion-precipitation phase transformation with the solvent system N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl) as solvent and water as coagulant. The effect of CH on membrane structure and performance was investigated. Owing to the strong hydrophilicity, CH chains enriched on the blend membrane surface and improved the hydrophilicity of the membrane. The addition of CH also led to the formation of finger-like pores and the increase of pore size and porosity. The flux and the flux recovery ratio (FRR) of the blend membrane were higher than that of pure PVDF membrane. The fouling resistance of the blend membrane was lower than that of PVDF original membrane. In a word, the addition of CH to PVDF membrane improved the hydrophilicity and the anti-fouling ability of PVDF membrane.

scholarly journals Tamisolve® NxG as an Alternative Non-Toxic Solvent for the Preparation of Porous Poly (Vinylidene Fluoride) Membranes

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2579
Author(s):  
Francesca Russo ◽  
Tiziana Marino ◽  
Francesco Galiano ◽  
Lassaad Gzara ◽  
Amalia Gordano ◽  
...  
Keyword(s):  
Pore Size ◽  
Vinylidene Fluoride ◽  
Water Solution ◽  
Chemical Properties ◽  
Solvent System ◽  
Solubility Parameters ◽  
Coagulation Bath ◽  
Separation And Purification ◽  
Pore Former ◽  
Poly Vinylidene Fluoride

Tamisolve® NxG, a well-known non-toxic solvent, was used for poly(vinylidene fluoride) (PVDF) membranes preparation via a non-solvent-induced phase separation (NIPS) procedure with water as a coagulation bath. Preliminary investigations, related to the study of the physical/chemical properties of the solvent, the solubility parameters, the gel transition temperature and the viscosity of the polymer–solvent system, confirmed the power of the solvent to solubilize PVDF polymer for membranes preparation. The role of polyvinylpyrrolidone (PVP) and/or poly(ethylene glycol) (PEG), as pore former agents in the dope solution, was studied along with different polymer concentrations (10 wt%, 15 wt% and 18 wt%). The produced membranes were then characterized in terms of morphology, thickness, porosity, contact angle, atomic force microscopy (AFM) and infrared spectroscopy (ATR-FTIR). Pore size measurements, pore size distribution and water permeability (PWP) tests placed the developed membranes in the ultrafiltration (UF) and microfiltration (MF) range. Finally, PVDF membrane performances were investigated in terms of rejection (%) and permeability recovery ratio (PRR) using methylene blue (MB) in water solution to assess their potential application in separation and purification processes.

scholarly journals Redox-Mediated Polymer Catalyst for Lithium-Air Batteries with High Round-Trip Efficiency

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1479
Author(s):  
Min-Cheol Kim ◽  
Jung Hyun Song ◽  
Young-Woo Lee ◽  
Jung Inn Sohn
Keyword(s):  
Vinylidene Fluoride ◽  
Cycling Performance ◽  
Redox Mediators ◽  
Round Trip ◽  
Multi Wall Carbon Nanotubes ◽  
Charge Process ◽  
Polymer Catalyst ◽  
Poly Vinylidene Fluoride ◽  
To Receive ◽  
Lithium Air Batteries

Lithium-air batteries (LABs) continue to receive attention as a promising power source because they possess a high theoretical energy density of 3436 Wh L−1. However, the remaining Li2O2 resulting from the irreversible decomposition of Li2O2 during the charge process is one of the key challenges so as to address the deterioration of the cycling performance of LABs. In this study, we propose and report a redox-mediated polymer catalyst (RPC) as a cathode catalyst being composed of LiI and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) with multi-wall carbon nanotubes (MWCNTs) as the cathode material. In the RPC, iodine molecules are chemically combined with the PVDF-HFP chain. The as-prepared RPC exhibits increased cycling performance by 194% and decreased overpotential by 21.1% at 0.1 mA cm−2 compared to the sample without LiI molecules. Furthermore, these results suggest that the RPC consisting of a polymer chain and redox mediators will be extensively utilized as highly efficient catalysts of LABs.

Piezoelectric Performance of PVDF Composites for Transportation Engineering: A Multi-Scale Simulation Study

2020 ◽  
Author(s):  
Xiao-Hong Yin ◽  
Jin-Wen Jian ◽  
Can Yang ◽  
Tian Lei ◽  
Tao Cheng
Keyword(s):  
Vinylidene Fluoride ◽  
Transportation Engineering ◽  
Piezoelectric Composites ◽  
Micro Scale ◽  
Multi Scale ◽  
Piezoelectric Energy ◽  
Cantilever Structure ◽  
Macro Scale ◽  
Poly Vinylidene Fluoride ◽  
Piezoelectric Performance

Abstract In the present work, the poly (vinylidene fluoride) composite filled with the lead zirconium titanate (PVDF/PZT) was numerically investigated focusing on the improvement of piezoelectric performance parameters. With a multi-scale simulation strategy, effects of the PZT fillers’ orientation and length on the electrical outputs of the piezoelectric energy collectors buried in the roads were systematically examined. Specifically, at the micro-scale, based on our previous research results, Comsol Multiphysics connected with Matlab was utilized to create the unit cell of piezoelectric composites. The simulation results showed that parameters of PZT nano-fillers greatly affect the piezoelectric coefficients. For the macro-scale simulation, a road energy collector with innovative symmetrical cantilever structure was designed, with piezoelectric constants obtained at micro-scale simulation as inputs. The correlation between the output voltage of the energy-collector and PZT parameters (i.e., orientation and length) was successfully developed by applying the vehicle’s axle-load. This work provides a way for tailoring the piezoelectric performance of the macro components (i.e., sensors) through adjusting the states of the fillers inside the piezoelectric composites.

Viscometric investigations on the intrinsic viscosity of polyvinylpyrrolidone affected by polymer-polymer interactions in solution

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Omar Melad Al-Azhar
Keyword(s):  
Intrinsic Viscosity ◽  
Vinylidene Fluoride ◽  
Solvent System ◽  
Repulsive Interaction ◽  
Solvent Method ◽  
Poly Vinyl Chloride ◽  
Poly Vinylidene Fluoride ◽  
Polymer Interactions ◽  
High Concentrations ◽  
Polymer Solvent

AbstractThe intrinsic viscosity of polyvinylpyrrolidone (PVP) and various added polymers was investigated by the polymer-solvent method. It has been found that both polymer-polymer interactions and the concentration of the added polymer affect the intrinsic viscosity of PVP. In the ‘polymer-solvent’ system poly(methyl methacrylate) + dimethylformamide (PMMA+DMF), the intrinsic viscosity of PVP decreases as the concentration of PMMA increases, showing that the repulsive interaction between PVP and PMMA originates from the contraction of PVP coils in solution due to the intermolecular excluded volume. However, in the polymersolvent systems poly(vinyl chloride) (PVC) + DMF or poly(vinylidene fluoride) (PVDF) + DMF, the attractive interactions between PVP and PVC or PVDF cause an expansion of PVP coils in solution at high concentrations of PVC or PVDF. The polymer-solvent method allows estimating the compatibility of the used polymers.

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