Formation and evolution of a bicontinuous structure of PMMA membrane during wet immersion process

Kuo, Chun-Yin; Su, Shiun-Lian; Tsai, Hui-An; Wang, Da-Ming; Lai, Juin‐Yih

doi:10.1016/j.memsci.2008.02.034

Cited by 16 publications

(4 citation statements)

References 31 publications

(35 reference statements)

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“…The difference between surface morphologies of PEI fibers electrospun from DMF and DMAc-based solutions can be rationalized in terms of principles of spinodal decomposition. Several authors studied − occurrence and evolution of SD during membrane formation. They found SD leads to cocontinuous network of interconnected pores which its retainment is threatened with coarsening and coalescence of phase separated domains.…”

Section: Resultsmentioning

confidence: 99%

Comparative Studies on the Solvent Quality and Atmosphere Humidity for Electrospinning of Nanoporous Polyetherimide Fibers

Fashandi

Karimi

2013

Ind. Eng. Chem. Res.

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Implications regarding requirements of performing a successive electrospinning and producing nanoporous polyetherimide (PEI) fibers are discussed through electrospinning PEI solutions of three nonvolatile solvents, that is, dimethylforamide (DMF), dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP), under atmospheres of constant temperature and varying levels of relative humidity (RH). The results demonstrate depending on nature of miscibility area in ternary phase diagram, a minimum RH is necessary to stabilize fiber formation. Furthermore, RH of operating environment affects diameter and both surface and interior morphologies of PEI electrospun fibers through involving the rate of phase demixing and viscoelasticity of solution. Considering fibers produced from NMP solutions because of delayed demixing, solvent drying precedes phase demixing or takes place in a comparable rate in high RH which leads to solid cross-section and texture-less surface with slight porosity. By choosing DMF or DMAc as electrospinning solvent, thicker fibers with rough surface and porous cross-section are expected.

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Section: Resultsmentioning

confidence: 99%

Comparative Studies on the Solvent Quality and Atmosphere Humidity for Electrospinning of Nanoporous Polyetherimide Fibers

Fashandi

Karimi

2013

Ind. Eng. Chem. Res.

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“…These results were consistent with Figure 6a and confirmed the bimodal membrane structure. In the FD procedure, the membrane morphology is fixed with a minimized distortion that may have occurred during normal drying, and thus low membrane shrinkage was expected, 28 which resulted in an intermediate influence of highly permeable regions on gas permeation.…”

Section: Effect Of Membrane Pretreatments On Nppmentioning

confidence: 99%

Structural Characterization of Thin-Film Polyamide Reverse Osmosis Membranes

Albo

Hagiwara

Yanagishita

et al. 2014

Ind. Eng. Chem. Res.

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This study aims to explore the structural characteristics of the inhomogeneous top layer of thin-film composite membranes when pretreated by different methods: room temperature−oven, ethanol−hexane in a solvent exchange process, and freeze-drying. An evaluation of the nano-order free-volume pore size of the polyamide samples was carried out by nanopermporometry (NPP) and was quantitatively compared with the free-volume pore estimated from normalized Knudsenbased permeance (NKP) and with positron annihilation characterization (PALS). NPP results denoted a bimodal polyamide membrane structure described by a dense matrix and highly permeable regions. The application of different condensable vapors (water, hexane, and isopropanol) resulted in a free-volume pore size smaller than d p = 0.6 nm for dense regions, which was confirmed after NKP and PALS. In addition, the influence of highly permeable regions on permeance decreased in the following order: ethanol−hexane > freeze-drying > room temperature−oven samples, demonstrating an effective membrane structure alteration after different pretreatments.

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“…The polymer's morphology is determined by the conditions in which its synthesis was carried out, usually by phase inversion, and a thorough analysis of this step is necessary to obtain polymers with properties suitable for use as a support for graphene membranes [47,54]. In addition to the different solvent/non-solvent combinations [40,54], other factors can influence the morphology of a polymer obtained by phase inversion, such as, for example, the drying method [55], exposure time to non-solvent [56], addition of non-solvent to the polymeric solution before the phase inversion [57], addition of surfactants [58][59][60] and addition of activated carbon [61].…”

Section: Composite Graphene Membranesmentioning

confidence: 99%

Graphene Membranes: From Reverse Osmosis to Gas Separation

Cecilia¹,

Feliciano²,

Santarosa³

2021

Int. J. Membrane Sci. Techno.

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Graphene membrane is a promising technology to help both carbon dioxide separation from flue gas and water desalination. This work reported the importance of membrane separation processes, the evolution of polymeric membranes before the discovery of graphene and how this material fits into this scenario. In addition, reverse osmosis and gas separations have been discussed as promising methods to reduce the occurrence of freshwater scarcity events and slow global warming. For all these separation techniques, the current state of graphene membranes technology and what advances might be brought by such one atom thick skin layer were presented, as well as the results of theoretical and experimental research. Finally, the challenges that still need to be overcome by this innovative technology as well as the perspectives were shown.

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Formation and evolution of a bicontinuous structure of PMMA membrane during wet immersion process

Cited by 16 publications

References 31 publications

Comparative Studies on the Solvent Quality and Atmosphere Humidity for Electrospinning of Nanoporous Polyetherimide Fibers

Comparative Studies on the Solvent Quality and Atmosphere Humidity for Electrospinning of Nanoporous Polyetherimide Fibers

Structural Characterization of Thin-Film Polyamide Reverse Osmosis Membranes

Graphene Membranes: From Reverse Osmosis to Gas Separation

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