Embodiments disclosed herein provide a pleatable freestanding isoporous block-copolymer (BCP) thin films fabricated sans substrate at a size suitable for fabricating pleated cartridges. The thin films have narrow pore size distribution, are mechanically robust, and have exceptional separation performance. These porous BCP thin films are useful as filtration media and separation membranes and are amenable to standard manufacturing practices.

Methods are herein provided for preparing a material for casting a flat-sheet, extruding a solid-fiber, and/or extruding a hollow-fiber utilizing a chlorinated aqueous amine solution as an effective solvent to form a crystalline polymorph structure of the material. This material in the form of, for example, an effective vapor permeable membrane can be used in membrane distillation to desalinate saline streams.

The very purpose of an improved oil recovery or an enhanced oil recovery method is to mobilize oil from an oil-bearing formation as stable wet oil emulsion to an oil gathering center. Yet, the very purpose of the latter is to de-stabilize such a stable emulsion using a multitude of redundant oil-water separation steps and bulky equipment. Methods are herein provided for preparing a material for casting a flat-sheet, extruding a solid-fiber, and/or extruding a hollow-fiber utilizing an aqueous amine solution as an effective solvent to form a crystalline polymorph structure of the material. This material in the form of, for example, an effective and selective oil-wet membrane can be used to simultaneously de-mix oil and water phases from a wet oil emulsion, whether the emulsion is stable or instable.

A dual-layer membrane and a method for preparing thereof. By adding a modifying monomer containing an active group and a characteristic group to a dope solution or spinning solution during the preparation of the dual-layer membrane, the grafting reaction occurs between the active group of the monomer and the polymer in the dope solution or spinning solution, and the intermolecular interaction with other polymers is enhanced by the characteristic group of the monomer, to improve the miscibility between the polymers. The method is suitable for preparing both a dual-layer flat sheet membrane and a dual-layer hollow fiber membrane, and can realize the preparation of a dual-layer membrane with an interpenetrated structure at the interface under mild preparation conditions.

An object of the present invention is to provide a porous hollow-fiber membrane satisfying both high strength and high pure-water permeation performance and at the same time, having high bending resistance. The present invention relates to a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane and when a photograph of a cross-section parallel to the longitudinal direction of the porous hollow-fiber membrane is binarized into a structure portion and a void portion, the following 1) and 2) are satisfied: 1) a proportion of an area of the void portion is from 20 to 50%, and 2) a value obtained by dividing a total of peripheral lengths of the void portions by a total of areas of the void portions is 2.0 m.sup.1 or less.

The present disclosure relates to a semipermeable membrane. The present disclosure aims to provide a semipermeable membrane having tolerance against a decrease over time in substance permeability. The present disclosure provides a semipermeable membrane containing a resin. The permeation rate of albumin in the semipermeable membrane is no lower than 30%. The albumin adsorption amount obtained when the semipermeable membrane measuring 1 cm on each side is immersed in a 0.1% albumin solution for 90 minutes is no greater than 10 g/cm.sup.2. The water permeation amount obtained when water is sucked through the semipermeable membrane at a negative pressure of 30.2 kPa is expressed by no smaller than 1,000 L/(m.sup.2 hour). The semipermeable membrane can isolate a cell from an external environment.

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.

A solution contains at least one sulfone polymer and N-tert.-butyl-2-pyrrolidone. The solution can be used in a process of making a membrane, which is useful for water treatment.

Embodiments of the present disclosure describe a method of making a membrane comprising contacting one or more membrane materials, a solvent, and a non-solvent at a first temperature sufficient to form a homogenous solution; casting the homogenous solution at about the first temperature; and adjusting the temperature to a second temperature sufficient to induce phase separation of the solvent and non-solvent and form a porous membrane.

A poly(methyl methacrylate) (PMMA) membrane having a highly porous, reticulated, 3-D structure suitable for lateral flow diagnostic applications is described. Also described is a method for producing a poly(methyl methacrylate) (PMMA) membrane that comprises the steps of mixing a suitable amount of PMMA, a solvent and a optionally one of either a co-solvent or a non-solvent to produce a solution, casting a thin film of the solution onto a support, and removal of the solvent from the solution to produce the PMMA membrane. A lateral flow diagnostic device comprising a highly porous PMMA membrane as a reaction membrane is also described.