The problem addressed by the present invention is to provide a separation membrane with superior permeation performance and separation performance and having few occurrences of defects. The present invention relates to a separation membrane wherein: the separation membrane has a layer (I) with a thickness of 0.5-100 ?m; letting, in a cross-section in the direction of thickness of the layer (I), region a be a region with a depth of 50-150 nm from a surface (surface A), region b a region with a depth of 50-150 nm from the other surface (surface B), and region c a region with a thickness of 100 nm where the depth from both surfaces is the same, the average pore diameter Pa for region a and the average pore diameter Pb for region b are both 0.3-3.0 nm and the average pore diameter Pc for region c is 3.0 nm or less; and the percentage of open area Ha for region a, the percentage of open area Hb for region b, and the percentage of open area Hc for region c satisfy the following equations. 2Hc<Ha 2Hc<Hb

Provided is a method for producing a porous polyimide film with which it is possible to suppress the occurrence of curling in the polyimide-fine particle composite film obtained by firing the unfired composite film. The method for producing a porous polyimide film of the present invention includes, in the following order: forming an unfired composite film using a varnish that contains a resin including polyamide acid and/or polyimide, fine particles, and a solvent; immersing the unfired composite film in a solvent including water; firing the unfired composite film to obtain a polyimide-fine particle composite film; and removing the fine particles from the polyimide-fine particle composite film.

The invention provides polymer-grafted and functionalized nonwoven membranes adapted for use in bioseparation processes, the membranes including a nonwoven web of polyester fibers having an average fiber diameter of less than about 1.5 microns, each of the plurality of polyester fibers having grafted thereon a plurality of polymer segments constructed of a methacrylate polymer, each polymer segment carrying a functional group adapted for binding to a target molecule. The invention also provides a method of bioseparation comprising passing a solution comprising the target molecule, such as a protein, through the nonwoven membrane of the invention such that at least a portion of the target molecule in the solution binds to the nonwoven membrane. A method for preparing a polymer-grafted and functionalized nonwoven membrane adapted for use in bioseparation processes is also provided.

The invention relates to manufacturing processes for waterproof and breathable porous polymer membranes by coating a substrate with a dispersion comprising polymer, coated particles and diluent and removing the particles by dissolution, wherein the particles are made of organic salts, metal salts or metal oxides and the coating material is selected from carboxylic acids and alkoxy silanes. The invention further relates to dispersions to obtain such membranes, to polymer membranes obtained, to shaped art ides containing such membranes; to the use of such membranes, shaped articles and intermediates.

The present invention provides a carbon membrane for fluid separation with which a high-pressure fluid can be separated and purified and which has excellent pressure resistance and is less apt to be damaged. The present invention relates to a carbon membrane for fluid separation, including: a core layer which has a co-continuous porous structure; and a skin layer which has substantially no co-continuous porous structure and is formed around the core layer.

Disclosed here are semi-permeable cross-linked polyvinyl alcohol (PVA) based membranes that can be used as supports for water purification membranes, and methods for their production. The cross-linked PVA-based membranes are cross-linked with the reaction product of poly-epoxides and OH groups from the PVA polymers. Methods according to the present disclosure include crosslinking dissolved PVA and dissolved poly-epoxides, casting the cross-linked PVA, and coagulating the cast polymer in a phase immersion precipitation process.

To provide: a purification method which uses a polyimide and/or polyamide imide porous membrane that exhibits excellent removal performance for impurities such as metals, and wherein a liquid that is a silylating agent liquid, a film forming material or a diffusing agent composition is an object to be purified; a purification method for purifying a silicon compound-containing liquid that contains a silicon compound which is capable of producing a silanol group by hydrolysis; a method for producing a silylating agent liquid, a film forming material or a diffusing agent composition, which uses the purification method; a filter medium which is composed of the above-described porous membrane; and a filter device which comprises the above-described porous membrane. A purification method for purifying a liquid, which comprises a step in which some or all of the liquid is caused to permeate through a polyimide and/or polyamide imide porous membrane having communicating pores from one side to the other side by means of differential pressure, and wherein the liquid is a silylating agent liquid, a film forming material or a diffusing agent composition that is used for diffusing a dopant into a semiconductor substrate.

A membrane contains a polymer composition is described. The polymer composition contains a) at least one polymer of PA, PVA, Cellulose CA, CTA, CA-triacetate blend, cellulose ester, cellulose nitrate, regenerated cellulose, aromatic, aromatic/aliphatic or aliphatic polyamide, aromatic, aromatic/aliphatic or aliphatic polyimide, PBI, PBIL, PAN, PAN-PVC copolymer, PAN-methallyl sulfonate copolymer, PEI, PEEK, sulfonated SPEEK, PPO, poly-carbonate, polyester, PTFE, PVDF, PP, a polyelectrolyte complex, PMMA, PDMS, aromatic, aromatic/aliphatic or aliphatic polyimide urethane, aromatic, aromatic/aliphatic or aliphatic polyamidimide, crosslinked polyimide or poly-arylene ether, PSU, PPSU and PESU, and b) at least one dope polymer DP1, which is a polyalkylene oxide with a molecular mass Mw of more than 100,000 g/mol and/or a K-value of 60 or 20 more.

Provided are a porous film having excellent surface smoothness and a method for producing the same. The surface roughness of a porous film of polyvinylidene fluoride, polyethersulfone, polyimide and/or polyamide-imide is Ra 30,000 ? or less. The opening diameter of the porous film is preferably from 100 nm to 5000 nm. The method for producing a porous film preferably includes a step for kneading a varnish containing fine particles and at least one resin selected from the group consisting of polyvinylidene fluoride, polyether sulfone, polyamic acid, polyimide, polyamide-imide precursor, and polyamide-imide. The varnish preferably has a viscosity at 25? C. of 0.1-3 Pa.Math.s, a solids fraction concentration of 10-50 mass %, and a fine particle average particle size of 10-5000 nm.

The present invention includes membranes comprising one or more cellulosic materials and wetting agent(s), and methods of making such membranes.