A study of thermodynamics and kinetics pertinent to formation of PVDF membranes by phase inversion

Sun, Chenggui; Kosar, Walter; Zhang, Yufeng; Feng, Xinbin

doi:10.1016/j.desal.2012.10.005

Cited by 61 publications

(39 citation statements)

References 37 publications

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“…Owing to high volatility of acetone, the cloud points could not be determined for this system. The modeled phase curves for PVDF–NMP/DMF/DMAc–Water system are also in close agreement with the experimental cloud point data available in literature .…”

Section: Resultssupporting

confidence: 86%

“…For all membranes, the steady state is reached within 10 min. Initial period of fast exchange of solvent–nonsolvent is considered as diffusion controlled and a simplified equation for solvent concentration is used to fit the experimental data .

\frac{C_{t}}{C_{\infty}} = m (t^{0.5} - t_{0}^{0.5})

where m depends on the diffusion coefficient of solvent, nonsolvent, volume of fluid taken, area of the membrane cast, and compaction factor.…”

Section: Resultsmentioning

confidence: 99%

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Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Kurada

2017

Polymer Engineering & Sci

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An extensive study of thermodynamics and kinetics of non‐solvent induced phase separation was carried out for poly(vinylidene fluoride)/solvent/water system for four different solvents. Literature available on semicrystalline polymers was mostly based on experimental cloud points, obtained to a narrow range of polymer concentration (<10 wt%), much less than the working range for membrane preparation (20–25 wt%). Aim of this work was to model the thermodynamic phase diagram using extended Flory–Huggins theory which was used as a tool, along with the kinetic data to obtain tailor‐made membranes with desired morphology and properties. Interaction parameters involving solvent, nonsolvent, and polymer played an important role to tune the porosity of the membrane. Thermodynamic calculation showed solvent N,N‐dimethyl acetamide resulted in the most porous membrane (permeability 5.4 × 10−11 m Pa−1 s−1) followed by N,N‐dimethyl formamide (permeability 4.2 × 10−11 m Pa−1 s−1), N‐methyl pyrrolidone (permeability 3.8 × 10−11 m Pa−1 s−1), and acetone (impermeable to water even at 1380 kPa), which was the densest one. Prepared membranes were characterized in terms of surface morphology, molecular weight cut‐off, tensile strength, pore volume distribution, crystallinity, and surface roughness, which were correlated to inferences based on thermodynamic and kinetic calculations. POLYM. ENG. SCI., 58:1062–1073, 2018. © 2017 Society of Plastics Engineers

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Section: Resultssupporting

confidence: 86%

\frac{C_{t}}{C_{\infty}} = m (t^{0.5} - t_{0}^{0.5})

where m depends on the diffusion coefficient of solvent, nonsolvent, volume of fluid taken, area of the membrane cast, and compaction factor.…”

Section: Resultsmentioning

confidence: 99%

Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Kurada

2017

Polymer Engineering & Sci

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“…The cloud point of each casting solution was acquired using the titration method as described in the previous work [37]. The test was conducted at 30°C in this work.…”

Section: Cloud Point Experimentsmentioning

confidence: 99%

Preparation of PVDF-CTFE hydrophobic membranes for MD application: Effect of LiCl-based mixed additives

Zheng

Wei

et al. 2016

Journal of Membrane Science

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a b s t r a c tHydrophobic flat-sheet membranes were prepared by poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) via the non-solvent induced phase separation (NIPS) process for membrane distillation (MD) application. Different types of LiCl-based mixed additives were applied to investigate their effects on membrane properties and MD performance. The membranes were evaluated in terms of membrane morphology, pore size and distribution, porosity, surface roughness, hydrophobicity, as well as the direct contact membrane distillation (DCMD) performance. Clear evidences were obtained that the mixed additives altered the phase inversion process, which resulted in the variation in membrane morphology, structure, properties and performance. The mass ratio of PEG/LiCl ranging from 5:0 to 0:5 was comprehensively investigated to study the synergistic effects of two additives on PVDF-CTFE membranes. The membrane M5 (PEG:LiCl ¼1:1, total content 8 wt% ) showed optimal properties and MD performance for combining the structure of higher hydrophobicity and pore interconnectivity, small pore size and narrow pore size distribution. The addition of LiCl to PEG-containing solutions benefited the solid-liquid demixing process, which increased the hydrophobicity, porosity, pore interconnectivity, and MD performance of the resultant membranes. While added PEG to LiCl-containing solutions showed slightly influences. Furthermore, it was also found that PVP/LiCl and glycerol/LiCl were not suitable for hydrophobic membrane preparation as they strikingly reduced membrane hydrophobicity. While H 3 PO 4 and H 2 O were confirmed suitable to mix with LiCl for hydrophobic PVDF-CTFE membrane preparation.

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“…[1][2][3] However, the strong hydrophobic nature of pure PVDF membrane always leads to low water permeability and easily fouling while treating aqueous solution containing some natural organic and colloidal matters which are prone to deposition and absorption onto membrane surface. [4][5][6][7][8][9][10][11] This inevitably depresses the lifetime of membrane and subsequently leads to more operation cost of the replacement.…”

mentioning

confidence: 99%

Engineering a Highly Hydrophilic PVDF Membrane via Binding TiO₂ Nanoparticles and a PVA Layer onto a Membrane Surface

Qin

Zhao

et al. 2015

ACS Appl. Mater. Interfaces

178

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A highly hydrophilic PVDF membrane was fabricated through chemically binding TiO2 nanoparticles and a poly(vinyl alcohol) (PVA) layer onto a membrane surface simultaneously. The chemical composition of the modified membrane surface was determined by X-ray photoelectron spectroscopy, and the binding performance of TiO2 nanoparticles and the PVA layer was investigated by a rinsing test. The results indicated that the TiO2 nanoparticles were uniformly and strongly tailored onto the membrane surface, while the PVA layer was firmly attached onto the surface of TiO2 nanoparticles and the membrane by adsorption-cross-linking. The possible mechanisms during the modification process and filtration performance, i.e., water permeability and bovine serum albumin (BSA) rejection, were investigated as well. Furthermore, antifouling property was discussed through multicycles of BSA solution filtration tests, where the flux recovery ratio was significantly increased from 20.0% for pristine PVDF membrane to 80.5% for PVDF/TiO2/PVA-modified membrane. This remarkable promotion is mainly ascribed to the improvement of surface hydrophilicity, where the water contact angle of the membrane surface was decreased from 84° for pristine membrane to 24° for PVDF/TiO2/PVA membrane. This study presents a novel and varied strategy for immobilization of nanoparticles and PVA layer on substrate surface, which could be easily adapted for a variety of materials for surface modification.

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A study of thermodynamics and kinetics pertinent to formation of PVDF membranes by phase inversion

Cited by 61 publications

References 37 publications

Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Preparation of PVDF-CTFE hydrophobic membranes for MD application: Effect of LiCl-based mixed additives

Engineering a Highly Hydrophilic PVDF Membrane via Binding TiO₂ Nanoparticles and a PVA Layer onto a Membrane Surface

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A study of thermodynamics and kinetics pertinent to formation of PVDF membranes by phase inversion

Cited by 61 publications

References 37 publications

Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Role of thermodynamic and kinetic interaction of poly(vinylidene fluoride) with various solvents for tuning phase inversion membranes

Preparation of PVDF-CTFE hydrophobic membranes for MD application: Effect of LiCl-based mixed additives

Engineering a Highly Hydrophilic PVDF Membrane via Binding TiO2 Nanoparticles and a PVA Layer onto a Membrane Surface

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Product

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Engineering a Highly Hydrophilic PVDF Membrane via Binding TiO₂ Nanoparticles and a PVA Layer onto a Membrane Surface