Poly(vinylidene fluoride) membranes by phase inversion: the role the casting and coagulation conditions play in their morphology, crystalline structure and properties

Buonomenna, Maria Giovanna; Macchi, Piero; Davoli, Mariano; Drioli, Enrico

doi:10.1016/j.eurpolymj.2006.12.033

Cited by 266 publications

(146 citation statements)

References 18 publications

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“…Gel polymer electrolytes, having the characteristics of both solid and liquid electrolytes, provide a promising strategy towards satisfied ionic conductivity, wide electrochemical window, and good compatibility with electrodes. The favorable polymer matrixes for gel polymer electrolytes include PEO, 221 poly(acrylonitrile), 222 poly(methyl methacrylate), 223 PVDF, 224 and PVDF based copolymers, such as PVDF-co-trifluoroethylene and PVDF-co-hexafluoropropylene. 225,226 The typically micrometer-sized pores in these polymer matrixes ensure facile pathways of lithium ions, but lack the ability to prevent soluble redox species from crossing over the membrane.…”

Section: Polymeric Electrolytesmentioning

confidence: 99%

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage

et al. 2015

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Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/ opportunities are comprehensively discussed.

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Section: Polymeric Electrolytesmentioning

confidence: 99%

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage

et al. 2015

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“…[5,13,14] The microstructure and crystalline phase of the polymer films in phase-inversion can be controlled by adjusting paramteres like composition, [5,12] type of solvent, [16,17] quenching temperature etc. [18,19] Although PVDF films formed by this technique can have high β-phase contents, they are mostly porous and not suitable for electroactive applications. Moreover, the β-phase crystals are randomly oriented in these PVDF films and show no specific directional preference.…”

mentioning

confidence: 99%

“…[5,17,19] This is attributed to the slow crystallization and elimination of the DMF owing to the decreased miscibility and mobility of DMF at lower temperatures. The films quenched at - with the further shoulder observed between 175 and 180C being attributed to the γ-phase.…”

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confidence: 99%

Exclusive self-aligned β-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion

et al. 2015

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Keywords: PVDF, piezoelectric effect, self-alignment, β-phase, Piezo Force Microscopy Poly(vinylidene fluoride), (PVDF), is one of the most attractive polymers owing to its remarkable pyro-, piezo-and ferro-electroactive properties. [1][2][3][4] These properties stem from its unique polymorphism which also gives rise to its extraordinary mechanical properties, high chemical resistance, good thermal stability and biocompatibility. [5] PVDF shows four significant crystalline phases α, β, δ and γ; [2,6] with the electroactive β-phase being utilized most frequently for the development of sensors, actuators [7,8] and microgenerators. [4,9,10] Owing to its importance, the formation of electroactive β crystalline phase has been intensively investigated through various routes, including melt casting, [15] solution deposition, [11] spin coating [12] and phase inversion. [13,14] While, the films or membranes formed by 2 melting/crystallisation are dominated by α-phase, [15] those obtained by spin-coating and further dried at temperature between 30-60 ºC are largely dominated by β-phase crystals. [12] For the phase inversion technique, PVDF films are formed by quenching the casting films into a nonsolvent bath to induce a series of liquid-solid and liquid-liquid phase separation events. [5,13,14] The microstructure and crystalline phase of the polymer films in phase-inversion can be controlled by adjusting paramteres like composition, [5,12] type of solvent, [16,17] quenching temperature etc. [18,19] Although PVDF films formed by this technique can have high β-phase contents, they are mostly porous and not suitable for electroactive applications. Moreover, the β-phase crystals are randomly oriented in these PVDF films and show no specific directional preference. Polarization under high electric field, [6,20] by Corona poling, [12] or by mechanical stretching [3,6,15] is subsequently carried out to obtain electroactive PVDF films. These operations need to be done at elevated temperatures (>80 o C), requiring high voltage equipment and films with dense structure and high β-phase content. Spontaneous formation of electroactive -phase in PVDF nanofibers formed by drawing was reported to have piezoelectric coefficient up to d33=58.5 pm/V. [25] Similarly, PVDF mesoscale rod arrays, without any poling process, too were also reported to possess good piezoelectric properties due to their high β content. [24] In both these cases, mechanical stretching and stress during the template guiding are believed to be responsible for the piezoelectric effect. Self-polarization of oriented β-phase crystals has also been observed in ultrathin (~20 nm) PVDF copolymer films by spin-coating or by Langmuir-Blodgett (LB) method, and is attributed to the built-in electric field, in-film stress and the strong interaction of PVDF molecules with polar water. [21,22,23] Generally speaking, PVDF films or membrane formed by melt casting, solution deposition, spin coating and phase inversion etc. do not exhibit aligned β-phase crystals without additional t...

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“…The polymer precipitation takes place due to the interdiffusion of solvent and antisolvent, with the rate of interdiffusion dependent on the solubility parameters of the solvent and antisolvent used. [47][48][49] It has previously been shown that the precipitate morphology depends on the type of solvent, antisolvent, and the presence of nanoparticles. 4 Figure 7(a) shows a SEM micrograph (taken at low magnification) of the PBT-coated CNF precipitate.…”

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confidence: 99%

Polymer crystallization and precipitation‐induced wrapping of carbon nanofibers with PBT

Mago

Kalyon

Fisher

2009

J of Applied Polymer Sci

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Carbon nanofibers (CNFs) have attracted significant interest because of their excellent mechanical, electrical, and physical properties. Recent advances in chemical functionalization strategies are anticipated to extend their utility in various applications. In this study, noncovalent methods of CNF functionalization utilizing solution crystallization and precipitation techniques were used to create hybrid nanostructures consisting of CNFs and poly(butylene terephthalate) (PBT). Key to this study is the finding that o-chlorophenol can be used as a suitable solvent to dissolve PBT to generate these nanostructures. PBT crystallization was documented via wideangle X-ray analysis and differential scanning calorimetry and was due to the nucleation effect of the CNFs. The sizes of the PBT crystals could be manipulated by altering the polymer concentration. The solution crystallization and precipitation techniques provide an alternative strategy to alter and control the nanostructure/polymer interface. The resulting nanohybrid structures may potentially find use in a broad range of applications including electronic devices, sensors, and as reinforcing agents in a polymer matrix.

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Poly(vinylidene fluoride) membranes by phase inversion: the role the casting and coagulation conditions play in their morphology, crystalline structure and properties

Cited by 266 publications

References 18 publications

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage

Exclusive self-aligned β-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion

Polymer crystallization and precipitation‐induced wrapping of carbon nanofibers with PBT

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