The present invention relates to a porous membrane including a polymer including a polyvinylidene fluoride-based resin as a main component, and a branched polyvinylidene fluoride-based resin as the polyvinylidene fluoride-based resin, in which the polymer has a value of a of 0.32 to 0.41 and a value of b of 0.18 to 0.42, each of which is determined by approximation according to the formula 1 below from a radius of gyration <S.sup.2>.sup.1/2 and an absolute molecular weight M.sub.w of the polymer which are measured by GPC-MALS (gel permeation chromatograph equipped with a multi-angle light scattering detector). <S.sup.2>.sup.1/2=bM.sub.w.sup.a (Formula 1)

A hollow fiber filtration membrane in which even when a relatively small contaminant having a size close to that of a permeation effective component is present in a filtration solution, Flux decrease over time during filtration is suppressed, and a useful component can be efficiently recovered, the hollow fiber filtration membrane including a polysulfone-based polymer and a hydrophilic polymer and having a large number of pores, the hollow fiber filtration membrane having a gradient asymmetric porous structure in which an average pore diameter of the pores increases from an outer surface portion toward an inner surface portion of the membrane, a content of the hydrophilic polymer of the membrane being from 6.0 to 10.0% by mass, a ratio between a content of the hydrophilic polymer at the inner surface portion and the content of the hydrophilic polymer of the membrane being in the range of from 0.50 to 0.80.

Porous filters having uniform pore size and close packing density are described, along with methods and apparatus for making the porous filters based on nanopatterning. One method includes applying a polymeric liquid to a mold consisting of an array of posts having a desired pore size and distribution. Solidification of polymeric membrane followed by separation from the mold produces a polymer membrane with a predetermined spaced array of pores. A pre-filter film can also be bonded with the membrane during formation to provide increased mechanical support and filtration of larger particles on the input side of the filter. Other process variants are described, including methods for incorporating additional functionalities to the filter.

[Problem] To provide a membrane for the forward osmosis method, which keeps a high porosity, reduces concentration polarization by appropriately controlling the pore distribution, achieves both high water permeability and a self-supporting property, and has high chemical durability such that the membrane is applicable to various draw solutions. [Solution] A separation membrane having a structure inclined from an outer surface side to an inner surface side, a ratio between a thickness of a dense layer having a dense polymer density and a thickness of a coarse layer having a coarse polymer density being in a range of 0.25≦(the thickness of the coarse layer)/[(the thickness of the dense layer)+(the thickness of the coarse layer)]≦0.6, when measuring polymer density distribution in a thickness direction of the separation membrane by Raman spectroscopy.

The invention provides a method of forming a membrane between a first volume of polar medium and a second volume of polar medium. In some embodiments, the method involves providing a first volume including polar medium and a second volume including polar medium which are separated from one another by an apolar medium, in which at least one of the first and second volumes has a layer including amphipathic molecules.

A thin film composite membrane (TFC) includes an active layer on a support. The active layer includes at least 8 barrier layers of star-polymers each having at least three linear polymers attached at a central core. Each of the barrier layers has a thickness between 5 and 50 nm, and the barrier layers have alternating charge.

A porous membrane is made from a poly(phenylene ether) copolymer containing 10 to 40 mole percent repeat units derived from 2-methyl-6-phenylphenol and 60 to 90 mole percent repeat units derived from 2,6-dimethylphenol; and a block copolymer containing backbone or pendant blocks of poly(C.sub.2-4 alkylene oxide). The porous membrane is made by dissolving the poly(phenylene ether) copolymer in a water-miscible polar aprotic solvent to form a membrane-forming composition; and phase-inverting the membrane forming-composition in a first non-solvent composition to form the porous membrane. A method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, includes coextruding the membrane-forming composition through the annulus, and a first non-solvent composition through the bore, into a second non-solvent composition to form the hollow fiber.

A separation module that includes a porous membrane, where the porous membrane includes a poly(phenylene ether) copolymer containing 10 to 40 mole percent repeat units derived from 2-methyl-6-phenylphenol and 60 to 90 mole percent repeat units derived from 2,6-dimethylphenol; and a block copolymer containing backbone or pendant blocks of poly(C.sub.2-4 alkylene oxide). The separation module can be used in devices for wastewater treatment, water purification, desalination, separating water-insoluble oil from oil-containing wastewater, membrane distillation, sugar purification, protein concentration, enzyme recovery, dialysis, liver dialysis, or blood oxygenation.

Provided is a method for preparing a gas separation membrane, the method including forming a porous layer by coating a hydrophilic polymer solution on a porous substrate; and forming an active layer by coating a composition for forming an active layer including a polymer of Chemical Formula 1 on the porous layer, ##STR00001## wherein in Chemical Formula 1, n is the number of a repeating unit, and is an integer of 500 to 3,000, and R1 to R5 are the same as or different from each other, and each independently is hydrogen, an alkyl group, or —(C═O)R6, and R6 is an alkyl group, wherein the polymer of Chemical Formula 1 is included in an amount from 1% by weight to 5% by weight based on the composition for forming an active layer, and a gas separation membrane prepared using the same.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.