According to one embodiment, a composition of matter includes: a first system of continuous voids arranged in a three-dimensional matrix; a second system of continuous voids arranged in the three-dimensional matrix; and a nanoporous barrier separating the first system of continuous voids and the second system of continuous voids. The first system of continuous voids and the second system of continuous voids are interwoven but independent so as to form a plurality of channels through the three-dimensional matrix. Corresponding methods for forming the composition of matter are also disclosed.

The purpose of the present invention is to provide a porous hollow fiber membrane that can efficiently separate and remove the substances to be removed such as small-particle virus contained in a solution and, at the same time, useful recovering substances such as protein can be efficiently permeated and the decrease of its transmission rate with elapse of time is small. The porous hollow fiber membrane of the present invention is characterized in that the filtration downstream surface thereof has dot-shaped or slit-shaped pores, the filtration upstream surface thereof is a network structure or a fine particle aggregate structure, the central region of the membrane is composed of a substantially homogeneous structure, the membrane wall is composed of a structure having substantially no macrovoids, the permeability for pure water is 10 to 300 L/(h.Math.m.sup.2.Math.bar) and the permeability for a 0.1% by weight solution of bovine γ-globulin is 30 to 100% of the permeability for pure water. Also, the hollow fiber membrane is characterized in that the permeability for a 0.1% by weight solution of bovine γ-globulin in a 20 mmol/L phosphate buffer is 30 to 100% of the permeability for a 0.1% by weight solution of bovine γ-globulin in a 20 mmol/L phosphate-buffered physiological saline solution.

A separation membrane structure comprises a porous suppor, and a separation membrane formed on the porous support. The separation membrane has an average pore diameter of greater than or equal to 0.32 nm and less than or equal to 0.44 nm. The separation membrane includes addition of at least one of a metal cation or a metal complex that tends to adsorb nitrogen in comparison to methane.

Microporous membranes comprising a single integral layer having first and second microporous surfaces; and, a porous bulk between the microporous surfaces, wherein the bulk comprises at least a first region and a second region; the first region comprising a first set of pores having outer rims, prepared by removing introduced silica dissolvable nanoparticles, the first set of pores having a first controlled pore size, and a second set of pores connecting the outer rims, the second set of pores having a second controlled pore size, and a polymer matrix supporting the first set of pores, wherein the first controlled pore size is greater than the second controlled pore size; the second region comprising a third set of pores prepared by phase inversion, the third set of pores having a third controlled pore size, filters including the membranes, and methods of making and using the membranes, are disclosed.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

Disclosed is a hollow fiber membrane having hexagonal voids, suitable for use in high throughput filtration applications. Thus, the membrane includes (i) an inner surface; (ii) an outer surface; and (iii) a porous bulk disposed therebetween, wherein the porous bulk comprises at least a first region including: a) a first set of pores having a first controlled pore size and having outer rims; b) a second set of pores connecting the outer rims of the first set of pores, wherein the pore size of the first set of pores is greater than the pore size of the second set of pores; and c) a polymer matrix supporting the first set of pores. Also disclosed is a method for preparing such hollow fiber membranes, which involves coating a filament with a coating composition that includes a membrane-forming polymer and dissolvable nanoparticles, followed by phase invention, and dissolving of the nanoparticles. The filament is removed to obtain the hollow fiber membrane.

The present invention provides methods for designing a filtration systems for capturing viable tumor cells, such as circulating tumor cells at high efficiency and high viability. The methods involve development of a set of “key engineering design parameters” that are crucial to achieve high tumor cell viability. These important design parameters include the filter geometry design, fluid delivery method, transfilter pressure and total filtration time.

At least a selected microporous membrane is made by a dry-stretch process and has substantially round shaped pores and a ratio of machine direction tensile strength to transverse direction tensile strength in the range of 0.5 to 6.0. The method of making the foregoing microporous membrane may include the steps of: extruding a polymer into a nonporous precursor, and biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction including a simultaneous controlled machine direction relax. At least selected embodiments of the invention may be directed to biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators, filtration media, humidity control media, flat sheet membranes, liquid retention media, and the like, related methods, methods of manufacture, methods of use, and the like.

Membranes comprising first and second microporous surfaces, and, a porous bulk between the surfaces, the bulk comprising first and second regions; the first region comprising a first set of pores having outer rims, and having controlled pore size, and a second set of pores connecting the outer rims of the first set of pores, the second set of pores having a controlled pore size, and a polymer matrix supporting the first set of pores; the second region comprising a third set of pores having outer rims, and having a controlled pore size, and a fourth set of pores connecting the outer rims of the third set of pores, the fourth set of pores having a controlled pore size, and a polymer matrix supporting the third set of pores; and methods of making and using the membranes, are disclosed.

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.