Provided is a porous hollow fiber membrane made of a thermoplastic resin, wherein a membrane thickness is 0.050 mm or larger and 0.25 mm or smaller, and when a strength coefficient is defined as K=(compressive strength)/((membrane thickness)/(inside diameter/2)).sup.3, K=1.7 or more.

The present invention is directed towards a method for the preparation of macroporous or mesoporous polymer films in hollow fiber geometry. The method according to the present invention reliably produces macroporous or mesoporous homopolymer or copolymer films in hollow fiber geometry having an ordered porous structure. Preferably, the pores are isoporous. The method involves the purging or casting a polyol adjacent to a film forming polymer solution of at least one homopolymer or at least one copolymer in a suitable solvent while polyol diffuses in and then condenses out of the film forming solution before the solution is immersed into a coagulation bath. The methods also require the presence of a carrier solution or carrier substrate during spinning or casting. The method makes macroporous or mesoporous film formation possible with a single step processing method.

An asymmetric hollow fiber (CMS) carbon molecular sieve is made by providing a dope solution comprised of a polvimide and a solvent, at a temperature greater than 250 C. that is less than the storage modulus at a temperature of 250 C., but no more than ten times less as measured using dynamic mechanical thermal analysis from 250 C. to a temperature where the polyimide carbonizes. The polvimide is shaped into a hollow polvimide fiber, the solvent removed and the polyimide hollow fiber is heated to pyroiyze the polvimide and form the asymmetric hollow carbon molecular sieve. The asymmetric hollow fiber carbon molecular sieve has a wall that is defined by an inner surface and outer surface of said fiber and the wall has an inner porous support region extending from the inner surface to an outer raicroporous separation region that extends from the inner porous support region to the outer surface. Surprisingly, when the polyimide has the particular storage modulus characteristics, the method allows for the hollow fiber CMS to be made without any pre-treatmenis or additives to inhibit stractural collapse of the inner microporous region.

A polymer ultrafiltration membrane with a bicontinuous highly interconnected porous structure, a preparation method and applications thereof are provided. The ultrafiltration membrane has a bottom layer and a polymer layer. The polymer layer is divided into a sublayer and a surface layer. The surface layer is of a uniform small pore structure with a narrow pore size distribution. The sublayer is of a bicontinuous highly interconnected three-dimensional network porous structure. The bicontinuous highly interconnected porous structure of the bicontinuous highly interconnected porous ultrafiltration membrane is characterized as follows: in the thickness direction of the sublayer, the cross-sectional porosity on any XY cross-section perpendicular to the thickness direction is 40-90%, preferably 60-90%, and further preferably 70-90%; and the difference in the cross-sectional porosities between any two XY cross-sections does not exceed 10%, preferably not exceed 8%, and also preferably not exceed 5%.

The present disclosure relates to improved semipermeable membranes based on acrylonitrile copolymers for use in dialyzers for the extracorporeal treatment of blood in conjunction with hemodialysis, hemofiltration or hemodiafiltration. The present disclosure further relates to methods of producing such membranes.

A novel process for making PBI films starting from gel PBI membranes polymerized and cast in the PPA process wherein acid-imbibed gel PBIs are neutralized in a series of water baths and undergo controlled drying in association with a substrate material, yielding a PBI film without the use of organic solvents.

A process for the preparation of ultrafiltration and microfiltration polymeric flat sheet separation membranes is disclosed, the process comprising a unidirectional cooling step. Membranes prepared according to the process exhibit numerous advantages over ultrafiltration and microfiltration membranes prepared via conventional processes. In particular, the membranes prepared by the present process exhibit remarkable pure water flux, superior mechanical properties and increased anti-fouling characteristics. Also disclosed are particular PVDF ultrafiltration and microfiltration membranes having improved flux, mechanical and anti-fouling properties.

A method of nanoscale patterning is disclosed. The method comprises: mixing predetermined amounts of a first solvent and a second solvent to generate a solvent, the first solvent and the second solvent being immiscible with each other; dissolving a solute material in the solvent to generate a coating material, the solute material having solubility that is higher in the first solvent than in the second solvent; and applying the coating material onto a substrate to form a plurality of pinholes in the coating material. The formation of the plurality of pinholes is associated with suspension drops mostly comprised of the second solvent, separated from the solute material dissolved in the first solvent, in the coating material. A method of making a stamp with a nanoscale pattern is also disclosed based on the above method.

A polysulfone-urethane copolymer is disclosed, which can be used as a membrane polymer, e.g., a matrix polymer, a pore forming agent, or both, while enhancing a membrane's blood compatibility. Methods are disclosed for forming the copolymer and incorporating the copolymer in membranes (e.g., spun hollow fibers, flat membranes) and other products.

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.