Hydrophobic flat membrane made from a vinylidene fluoride polymer with a wall, a first surface, and a second surface. The membrane has on its first surface a network structure with open pores and on its second surface a continuous skin in which pores are formed, and adjacent to the skin of the second surface a supporting layer with an isotropic pore structure across the wall thickness, wherein the supporting layer extends over at least 80% of the wall thickness and wherein the pores of the supporting layer have an average diameter of less than 1 m. The weight average of the molecular weight M.sub.W of the vinylidene fluoride polymer lies in the range from 300 000 to 500 000 daltons, and the polydispersivity M.sub.W/M.sub.N is greater than 5.5. The pores in the skin of the second surface have a closed perimeter in the plane of the skin and an average ratio of the extension in the direction of the longest axis thereof to the extension in the direction of the shortest axis thereof of at most 5. The pores in the first surface and second surface have an essentially isotropic distribution of their orientation. The porosity of the membrane lies in the range from 50 to 90 vol. % and the wall thickness in the range from 50 to 300 m. The membrane has a maximum separating pore diameter d.sub.max in the range from 0.05 to 1.5 m.

Providing a membrane-forming solution suitable for producing a separation membrane such as a hollow fiber membrane and a flat membrane. A membrane-forming solution including triacetylcellulose having an acetyl group substitution degree of 2.7 or higher, a good solvent for thermally induced phase separation and a poor solvent for thermally induced phase separation, wherein the good solvent is capable of heat-dissolving the triacetylcellulose (at a solid content concentration of 25 mass %), and the poor solvent is incapable of dissolving the triacetylcellulose up to the heat dissolution temperature of the good solvent, wherein both the good solvent and the poor solvent are included so as to enable phase separation of the heat-dissolved triacetylcellulose solution while the heat-dissolved triacetylcellulose solution is cooled to room temperature (from 20 to 30 C.), and wherein a mixing ratio in a total amount of the good solvent and the poor solvent is from 5 to 40 mass % of the good solvent and from 60 to 95 mass % of the poor solvent.

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.

A peak intensity of a (110) plane is greater than or equal to 2.5 times a peak intensity of a (004) plane in an X-ray diffraction pattern obtained by irradiation of X-rays to a membrane surface of the AFX membrane.

The present invention provides a porous hollow fiber membrane suitable for the removal of minute substances, e.g., viruses, contained in a liquid. The present invention relates to a porous hollow fiber membrane which is provided with a separation-functioning layer containing a fluororesin, has a gas diffusion amount of 0.5 to 5.0 mL/m.sup.2/hr as measured in a diffusion test, and also has foaming points at a density of 0.005 to 0.2 point/cm.sup.2 as measured in a foaming test under the immersion in 2-propanol.

The present invention is an integral multilayered composite membrane having at least one ultrafiltration layer made by cocasting or sequentially casting a plurality of polymer solutions onto a support to form a multilayered liquid sheet and immersing the sheet into a liquid coagulation bath to effect phase separation and form a multilayered composite membrane having at least one ultrafiltration layer.

Disclosed herein are asymmetric thin-film composite membranes and methods of making and using the same. Also included herein are asymmetric thin-film composite membranes for preventing and/or reducing microfouling or macrofouling. Additionally included herein are asymmetric thin-film composite membranes for preventing and/or reducing biofilm.

The porous hollow-fiber membrane of the present invention comprises a fluororesin polymer, and has columnar structures oriented in the longitudinal direction thereof. In the porous hollow-fiber membrane, molecular chains of the fluororesin polymer have been oriented in the longitudinal direction of the porous hollow-fiber membrane and have an average value of Raman orientation parameter of 1.5-4.0.

A method of preparing a hybrid membrane, the method including: evenly mixing a granular material and a dispersant, to yield a dispersion solution; evenly mixing a polymer and an organic solvent, to yield a matrix solution; adding the matrix solution to the dispersion solution to yield a mixed solution; heating the mixed solution to remove the dispersant, to yield a casting solution; and coating the casting solution on a substrate, followed by removal of the organic solvent, to yield a hybrid membrane.