Provided is a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose (preferably, hydroxypropyl cellulose) retained in the porous membrane, the hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000. The hydrophilic porous membrane of embodiments of the invention has high water permeability and can pass an integrity test in the case of being used as a filtration membrane of a filter cartridge. Also provided is a method for producing the above-mentioned hydrophilic porous membrane, the method comprising causing a hydrophilizing liquid including 0.005% to 0.500% by mass of a hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000, to permeate a porous membrane.

The present disclosure provides a fluorine-based resin porous membrane exhibiting high mechanical strength and low heat shrinkage rate while having a fine pore size, and a method for preparing the same.

Disclosed is a porous hollow fiber membrane containing a polysulfone-based polymer as a main component, which has an asymmetric structure in which the inner surface side is dense and the outer surface side is coarse, wherein an average of a minor axis diameter of pores of an inner surface is 20 nm or more and 40 nm or less, an open porosity of the inner surface is 10% or more and 30% or less, and a polymer including a monocarboxylic acid vinyl ester unit is supported on at least one of the outer surface and the inner surface. The present invention provides a hollow fiber membrane which has excellent removing performance of substances to be separated such as viruses, and can be used as a separation membrane having high permeability even in a treatment under low pressure.

When the porous membrane, which has two surfaces of a surface A and a surface C, is equally divided in the thickness direction of the porous membrane into three layers of a first layer including the surface A, a second layer that is a central layer in the thickness direction, and a third layer including the surface C, an average trunk size of the third layer is larger than an average trunk size of the second layer, and when a continuous layer from the surface A having a thickness of 10 m in the first layer is a first layer component, a continuous layer component having a thickness of 10 m and an average trunk size smaller than an average trunk size of the first layer component is present in the first layer, the second layer, and the third layer other than the first layer component.

The present invention provides a fluid separation membrane that can maintain separation performance for a long period of time. The present invention provides a fluid separation membrane including a separation layer including a dense layer, wherein 2 to 10,000 ppm of a total of a monocyclic or bicyclic aromatic compound being liquid or solid at 16 C. under atmospheric pressure and 10 to 250,000 ppm of water are adsorbed.

Disclosed herein are porous asymmetric silicon membranes. The membranes are characterized by high structural stability, and as such are useful as anode components in lithium ion batteries.

A hollow fiber membrane of the present invention is a hollow fiber membrane having an outer surface and an inner surface, wherein the inner surface has a zebra stripe pattern in which dense portions and porous portions are alternately formed in the longitudinal direction, and the outer surface has a maximum pore size of about 1 m or less (about 1 m), and wherein the hollow fiber membrane has a water permeability (flux) of about 1,300 LMH/bar to about 5,000 LMH/bar.

A method for forming an isoporous graded film comprising multiblock copolymers and isoporous graded films. The films have a surface layer and a bulk layer. The surface layer can have at least 110.sup.14 pores/m.sup.2 and a pore size distribution (d.sub.max/d.sub.min)) of less than 3. The bulk layer has an asymmetric structure. The films can be used in filtration applications.

[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 are 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 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