A polymer blend membrane includes a polyether-based copolymer and a polyether polymerized in situ and has high permeability and high selectivity for carbon dioxide. In the polymer blend membrane, the free volume of the polyether-based copolymer is greatly increased, and the adsorption capacity for carbon dioxide is enhanced. Thus, it can have excellent mechanical properties and excellent permeability and selectivity for carbon dioxide.

A composite semipermeable membrane includes a porous support membrane, a separation functional layer containing a polyamide disposed on the porous support membrane, and a coating layer disposed on the separation functional layer, wherein a water contact angle of a surface of the coating layer is 40° or less, and a protein adsorption force of the surface of the coating layer is 0.4 nN or less.

A composite semipermeable membrane includes a porous support membrane, a separation functional layer containing a polyamide disposed on the porous support membrane, and a coating layer disposed on the separation functional layer, wherein a water contact angle of a surface of the coating layer is 40° or less, and a protein adsorption force of the surface of the coating layer is 0.4 nN or less.

The present invention relates to a separation membrane including a thermoplastic polymer selected from a cellulose ester and a polyamide, in which, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval are defined as regions 1 to 5, all the regions 1 to 5 have a number average pore diameter changing rate a of −0.25 to 0.25, and at least one of the regions 1 to 5 is a region P that satisfies conditions (a) and (b): (a) a value of area average pore diameter D.sub.s/number average pore diameter D.sub.n is 2.50 to 6.00; and (b) a number average W of fine pores that are located at a distance smaller than L.sub.a from a center of respective coarse pores is 10 to 30.

The present invention relates to a separation membrane including a thermoplastic polymer selected from a cellulose ester and a polyamide, in which, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval are defined as regions 1 to 5, all the regions 1 to 5 have a number average pore diameter changing rate a of −0.25 to 0.25, and at least one of the regions 1 to 5 is a region P that satisfies conditions (a) and (b): (a) a value of area average pore diameter D.sub.s/number average pore diameter D.sub.n is 2.50 to 6.00; and (b) a number average W of fine pores that are located at a distance smaller than L.sub.a from a center of respective coarse pores is 10 to 30.

A hybrid membrane, particularly of polyacrylonitrile (PAN)/graphene oxide (GO)/SiO.sub.2, separates oil and water even from emulsions. The membrane can be made by one-step electrospinning, adding GO and SiO.sub.2 nanofillers in PAN in various concentrations. The nanofillers may be uniformly embedded in the nanofibrous structure of the electrospun hybrid membrane, with GO mainly embedded inside the PAN nanofibers and may cause knots, and/or SiO.sub.2 nanoparticles embedded on the nanofiber surface and may form micro-nano fiber surface protrusions. Hierarchical structures formed can have enhanced hydrophilicity due to oxygen-containing groups on both SiO.sub.2 and GO, and have >99% oil rejection from oil-water emulsions. Separation flux and phase rejection of gravity separation may be enhanced by incorporation of nanofillers, which may also enhance membrane mechanical properties. Separated water flux may be enhanced from 2600 (pure PAN) to 3151 Lm.sup.−2h.sup.−1 for the hybrid.

A graft copolymer including zwitterionic repeat units and hydrophobic repeat units, in which the zwitterionic repeat units constitute 2-60 wt % of the graft copolymer and each of the hydrophobic repeat units is characterized in that a homopolymer formed thereof is miscible with polyvinylidene fluoride, polysulfone, poly ether sulfone, polyvinyl chloride, or polyacrylonitrile, each of the hydrophobic repeat units not being a repeat unit of polyvinylidene fluoride. Also disclosed is a filtration membrane containing such a graft copolymer or a statistical copolymer that includes the same composition of repeat units as the graft copolymer. Further disclosed are methods of preparing the graft copolymer and the filtration membrane.

The present invention pertains to composition suitable for manufacturing membranes based on vinylidene fluoride (VDF) polymers, to porous membranes thereof, to methods for their manufacture and to uses thereof, especially for the filtration of water phases. Said composition comprising vinylidene fluoride (VDF) polymers and polymer additives comprising zwitterionic moieties delivers outstanding hydrophilization performances of manufactured membranes.

Charge mosaic membranes useful for desalination applications, and methods of making and using the same, are described.

A composite porous membrane contains at least one porous base layer and at least one uniaxially stretched coating layer located on at least one side surface of the porous base layer. For example, the composite porous membrane comprises at least one porous base layer and at least one nanofiber-like non-polyolefin polymer porous layer oriented along the transverse stretching direction of the composite porous membrane and located on one or two side surfaces of the porous base layer, or the composite porous membrane comprises a biaxially stretched polypropylene porous base layer and a uniaxially stretched coating layer located on at least one side surface of the porous base layer. The composite porous membrane is coated with a coating solution prior to transversely stretching. The nanofiber-like non-polyolefin polymer porous layer may reduce cracking of the composite porous membrane in the machine direction.