The Effect of Chain Structures on the Crystallization Behavior and Membrane Formation of Poly(Vinylidene Fluoride) Copolymers

Ma, Wenzhong; Yuan, Haoge; Wang, Xiaolin

doi:10.3390/membranes4020243

Cited by 39 publications

(26 citation statements)

References 21 publications

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“…[ 17 ] The X‐ray diffraction (XRD) patterns show that the characteristic peaks of α‐phase polyvinylidene fluoride (PVDF) disappear after gelation, which is attributed to the plasticizing effect of the IL (Figure S5a, Supporting Information). [ 18 ] The differential scanning calorimetry (DSC) curve (Figure S5b, Supporting Information) shows the melting temperature ( T m ) of PVDF‐HFP at around 146 °C. The gelation of ILE into the PVDF‐HFP matrix decreases T m to 119 °C.…”

Section: Resultsmentioning

confidence: 99%

Amine‐Functionalized Boron Nitride Nanosheets: A New Functional Additive for Robust, Flexible Ion Gel Electrolyte with High Lithium‐Ion Transference Number

Kim

Liu

et al. 2020

Adv Funct Materials

108

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Ion gel electrolytes show great potential in solid-state batteries attributed to their outstanding characteristics. However, because of the strong ionic nature of ionic liquids, ion gel electrolytes generally exhibit low lithium-ion transference number, limiting its practical application. Aminefunctionalized boron nitride (BN) nanosheets (AFBNNSs) are used as an additive into ion gel electrolytes for improving their ion transport properties. The AFBNNSs-ion gel shows much improved mechanical strength and thermal stability. The lithium-ion transference number is increased from 0.12 to 0.23 due to AFBNNS addition. More importantly, for the first time, nuclear magnetic resonance analysis reveals that the amine groups on the BN nanosheets have strong interaction with the bis(trifluoromethanesulfonyl)imide anions, which significantly reduces the anion mobility and consequently increases lithium-ion mobility. Battery cells using the optimized AFBNNSs-ion gel electrolyte exhibit stable lithium deposition and excellent electrochemical performance. A LiFePO 4 |Li cell retains 92.2% of its initial specific capacity after the 60th cycle while the cell without AFBNNSs-gel electrolyte only retains 53.5%. The results not only demonstrate a new strategy to improve lithium-ion transference number in ionic liquid electrolytes, but also open up a potential avenue to achieve solid-state lithium metal batteries with improved performance. and high safety levels. Lithium metal batteries (LMBs), owing to the low redox potential (−3.04 V vs standard hydrogen electrode) and ultrahigh theoretical capacity (3860 mAh g −1 ) of the lithium (Li) metal anode, are promising to fulfill these requirements. [1] However, the organic liquid electrolyte (LE), currently widely used in the LMBs, makes LMBs face severe safety concerns such as electrolyte leakage and combustion due to the intrinsic fluidity, flammability, and electrochemical instability. Replacing the organic liquid electrolyte with solid-state electrolytes (SSEs) has been proven to be an efficient way to overcome these problems. [2] Because of their high mechanical stability and structural integrity, SSEs enable facile cell fabrication and prevent electrolyte leakage, offering greater safety than liquid electrolytes. Current solid-state electrolytes include solid polymer electrolytes (SPEs) and inorganic electrolytes (IEs). Unfortunately, SPEs suffer from a poor ionic conductivity at room temperature, while the IEs show innate brittleness and intrinsically narrow electrochemical stability along with high contact resistance. Compared to SPEs and IEs, gel electrolytes, which are prepared by entrapping liquid electrolytes into a solid matrix, provide exceptional properties such as high ionic conductivity, low interfacial resistance, good mechanical strength, and flexibility.Liquid mediums are one of the key components in gel electrolytes. Among the candidates, ionic liquids (ILs), also known as room temperature molten salts, can result in high performance gel electrolytes because of the...

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Section: Resultsmentioning

confidence: 99%

Amine‐Functionalized Boron Nitride Nanosheets: A New Functional Additive for Robust, Flexible Ion Gel Electrolyte with High Lithium‐Ion Transference Number

Kim

Liu

et al. 2020

Adv Funct Materials

108

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“…Further, the surface morphology of polymer and copolymers are generally different in terms of spherulite size and organization [15].…”

Section: Introductionmentioning

confidence: 99%

Poly(vinylidene fluoride) and copolymers as porous membranes for tissue engineering applications

et al. 2015

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a b s t r a c tPoly(vinylidene fluoride) (PVDF) and its main copolymers -poly(vinylidene fluoride-cohexafluoropropene), P(VDF-HFP), and poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) -were processed by solvent casting at room temperature in the form of porous membranes. Copolymer membranes showed higher degree of porosity than PVDF, the average pore size being larger for P(VDF-TrFE) than for P(VDF-HFP) and PVDF. All membranes show high hydrophobicity with water contact angles in the range 94 to 115 , and electroactive beta phase contents above 90%. The adhesion and proliferation of both C2C12 myoblast and MC3T3-E1 pre-osteoblast cells on the membranes were investigated. It is demonstrated that PVDF membranes promote higher cell proliferation while P(VDF-HFP) membranes show the lowest proliferation for both kinds of cell. The proliferation on P(VDF-TrFE) membranes is cell dependent, higher for MC3T3-E1 cells but lower for C2C12 cells, related to the effect of the highly porous structure on the preferred morphology of each cell type, as the higher pore size and porosity of the P(VDF-TrFE) membrane induce cell elongation, which is preferred just by the C2C12 muscle cells.

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“…Characteristic peaks of the α and β crystalline phases of PVDF could not be clearly identified in the spectra due to a broad, intense peak at about 2 θ = 20.4°. The crystalline form of PVDF typically exhibits a mixture of these α and β crystalline domains . In the membranes produced here, the relative intensity of the broad peak decreases with the addition and increasing percentage of PVP as a component of the casting solution.…”

Section: Resultsmentioning

confidence: 77%

Positron annihilation lifetime spectroscopy study of polyvinylpyrrolidone‐added polyvinylidene fluoride membranes: Investigation of free volume and permeation relationships

Eren

Guney

et al. 2020

Journal of Polymer Science

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Polyvinylidene fluoride (PVDF) membranes were prepared via the phase inversion method from casting solutions containing PVDF, dimethylformamide (DMF), and polyvinylpyrrolidone (PVP) as pore former. PVP was used in the casting solution in a range of 0–5 wt % and extracted. The effect on membranes of using PVP in the casting process was analyzed by X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, viscosity, and water permeability techniques. With an increase of PVP from 0 to 5 wt %, the PVDF casting solution viscosities increased from 858 to 1148 cP; the resulting PVDF membrane thickness increased; and the crystallinity of PVDF membranes decreased from 40.0 to 33.3%, which indicates that the addition of PVP inhibits the degree of crystallization in the PVDF membranes. SEM results revealed the shape and size of macropores in the membranes; these macropores changed after PVP addition to the casting solutions. The impact of structural changes on free‐volume properties was evaluated using positron annihilation lifetime spectroscopy (PALS) studies. PALS analysis indicated no effect on the average radius (~3.4 Å) of membrane free‐volume holes from the addition of PVP to the casting solution. However, the percentage of o‐Ps pick‐off annihilation intensity, I3, increased from 1.7 to 5.1% with increased PVP content. Further, increasing the PVP content from 0.5 to 5% resulted in an increased final pure water permeability flux. For instance, the 210 min flux for a 14% PVDF + 0.5% PVP membrane was found to be 3.3 times greater than a control membrane having the same PVDF concentration. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 589–598

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The Effect of Chain Structures on the Crystallization Behavior and Membrane Formation of Poly(Vinylidene Fluoride) Copolymers

Cited by 39 publications

References 21 publications

Amine‐Functionalized Boron Nitride Nanosheets: A New Functional Additive for Robust, Flexible Ion Gel Electrolyte with High Lithium‐Ion Transference Number

Amine‐Functionalized Boron Nitride Nanosheets: A New Functional Additive for Robust, Flexible Ion Gel Electrolyte with High Lithium‐Ion Transference Number

Poly(vinylidene fluoride) and copolymers as porous membranes for tissue engineering applications

Positron annihilation lifetime spectroscopy study of polyvinylpyrrolidone‐added polyvinylidene fluoride membranes: Investigation of free volume and permeation relationships

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