The formation mechanism of phase inversion membranes

Strathmann, H.; Kock, K. N. de

doi:10.1016/s0011-9164(00)88244-2

Cited by 582 publications

(314 citation statements)

References 11 publications

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“…For the controle membrane, the fast formation of the rigid PSf matrix prevents the growth of the polymer-lean droplets (spongy structure) in between the macrovoids 46,47 . It is well known that the structure of the membrane is affected by the kinetic diffusion of solvent and non solvent.…”

Section: Membrane Morphologymentioning

confidence: 99%

Effects of Methylcellulose on the Properties and Morphology of Polysulfone Membranes Prepared by Phase Inversion

et al. 2017

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Polymer solutions of polysulfone (PSf) and methylcellulose (MC) in 1-methyl-2-pyrrolidone (NMP) were used to prepare ultrafiltration membranes by the phase inversion technique via immersion precipitation. The effect of MC additive on the structure and performances of the membranes was studied. The obtained membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR-ATR), equilibrium water content (EWC), water contact angle, porosity and ultrafiltration experiments of polyethylene glycol solutions. It was found that all the PSf/MC membranes had higher porosity, more hydrophilic surface and more vertically finger like pores than PSf membrane. With an increase in MC content in the casting solution from 0.5% to 1.5%, the hydraulic permeability increases from 17.17 to 118.46 L.m -2 .h -1 .bar -1 , while the rejection decreases from 91.82% to 64.45% with PEG 35000. DSC scan and FTIR analysis confirmed that methylcellulose was trapped in the membranes matrix.

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Section: Membrane Morphologymentioning

confidence: 99%

Effects of Methylcellulose on the Properties and Morphology of Polysulfone Membranes Prepared by Phase Inversion

et al. 2017

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“…To this end, from the Ct vs. t data, generated with the aid of equation . (5) and displayed in Tables 2 and 3, the 'no skin diffusion coefficients' Dr were computed with the help of equation (1). We compared these Dfvalues to the Dfs values for which the C~ vs. t curves were calculated (i.e.…”

Section: Results Of the Model Calculationsmentioning

confidence: 99%

Diffusion of solvent from a cast cellulose acetate solution during the formation of skinned membranes

Altena¹,

Smid²,

Berg³

et al. 1985

Polymer

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The transport of solvent out of a cast cellulose acetate (CA) solution into the coagulation bath during membrane formation is treated as a diffusion process. From the increase of solvent concentration in the bath with time (solvent leaching experiments) an overall solvent diffusion coefficient has been calculated. In size these coefficients compare well to mutual pseudo-binary solvent-non-solvent diffusion coefficients determined by means of a classical boundary broadening method applied to ternary solutions with fixed CA concentration, but with a gradient in solvent-nonsolvent composition. Since binary polymer-solvent interdiffusion coefficients are at least one order of magnitude lower, it is concluded that the diffusion of solvent into the coagulation bath is essentially a pseudo-binary solvent-non-solvent diffusion process. Combination of experimental results with model calculations for the effect of a thin dense skin on the diffusion of solvent out of the sublayer shows that the casting-leaching diffusion coefficient can be used to describe the out-diffusion of solvent from the layer under the skin provided that the relative skin resistance is not too high, or that the skin thickness is small.

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“…(Figure 15). The process is similar to the preparation of asymmetric polymeric membranes by the Loeb-Sourirajan phase inversion method (Strathmann and Kock, 1977). In this process, a casting solution composed of a polymer/solvent mixture is immersed into the nonsolvent coagulation bath.…”

Section: Nanoclustersmentioning

confidence: 99%

Structured microparticles with tailored properties produced by membrane emulsification

Vladisavljević

2015

Advances in Colloid and Interface Science

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This paper provides an overview of membrane emulsification routes for fabrication of structured microparticles with tailored properties for specific applications. Direct (bottom-up) and premix (top-down) membrane emulsification processes are discussed including operational, formulation and membrane factors that control the droplet size and droplet generation regimes. A special emphasis was put on different methods of controlled shear generation on membrane surface, such as cross flow on the membrane surface, swirl flow, forward and backward flow pulsations in the continuous phase and membrane oscillations and rotations. Droplets produced by membrane emulsification can be used for synthesis of particles with versatile morphology (solid and hollow, matrix and core/shell, spherical and non-spherical, porous and coherent, composite and homogeneous), which can be surface functionalised and coated or loaded with macromolecules, nanoparticles, quantum dots, drugs, phase change materials and high molecular weight gases to achieve controlled/targeted drug release and impart special optical, chemical, electrical, acoustic, thermal and magnetic properties. The template emulsions including metal-in-oil, solid-in-oil-in-water, oil-in-oil, multilayer, and Pickering emulsions can be produced with high encapsulation efficiency of encapsulated materials and narrow size distribution and transformed into structured particles using a variety of different processes, such as polymerisation (suspension, mini-emulsion, interfacial and in-situ), ionic gelation, chemical crosslinking, melt solidification, internal phase separation, layer-by-layer electrostatic deposition, particle self-assembly, complex coacervation, spray drying, sol-gel processing, and molecular imprinting. Particles fabricated from droplets produced by membrane emulsification include nanoclusters, colloidosomes, carbon aerogel particles, nanoshells, polymeric (molecularly imprinted, hypercrosslinked, Janus and core/shell) particles, solder metal powders and inorganic particles. Membrane 2 emulsification devices operate under constant temperature due to low shear rates on the membrane surface, which range from (1−10) × 10 3 s −1 in a direct process to (1−10) × 10 4 s −1 in a premix process.Keywords: Membrane Emulsification; Polymeric microsphere; Microgel; Janus Particle; Core/Shell Particle, Colloidosome. Membrane emulsificationMembrane emulsification (ME) involves preparation of emulsions by pressing a pure dispersed phase or pre-emulsified mixture of the dispersed and continuous phase through a microporous membrane under controlled injection rate and shear conditions. In direct membrane emulsification (DME), one liquid (a dispersed phase) is injected through a microporous membrane into another immiscible liquid (the continuous phase) (Nakashima et al., 1991;, which leads to the formation of droplets at the membrane/continuous phase interface ( Figure 1a). In premix membrane emulsification (PME) (Figure 1b), a pre-emulsion is pressed through the membrane (...

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The formation mechanism of phase inversion membranes

Cited by 582 publications

References 11 publications

Effects of Methylcellulose on the Properties and Morphology of Polysulfone Membranes Prepared by Phase Inversion

Effects of Methylcellulose on the Properties and Morphology of Polysulfone Membranes Prepared by Phase Inversion

Diffusion of solvent from a cast cellulose acetate solution during the formation of skinned membranes

Structured microparticles with tailored properties produced by membrane emulsification

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