The invention relates to the field of membrane gas separation and can be used for the energy-efficient fractionation of hydrocarbon mixtures, including separation and drying of natural and associated petroleum gases. Proposed is a method of fractionating mixtures of low molecular weight hydrocarbons which is based on the capillary condensation of the components of a mixture in the pores of microporous membranes with uniform porosity and a pore diameter in a range of 5 to 250 nm, wherein, for capillary condensation, the temperature of the membrane and the pressure on the permeate side are kept below the temperature and the pressure of the feed mixture such that the equilibrium pressure of the saturated vapors of the separated components on the permeate side is lower than the partial pressure of the components in the feed stream. This method makes it possible to significantly increase membrane permeability with respect to condensable components (over 500 m.sup.3/(m.sup.2.Math.atm.Math.h) for n-butane), and also component separation factors (the n-C.sub.4H.sub.10/CH.sub.4 separation factor is greater than 60 for a mixture having an associated petroleum gas composition), while also making it possible to dispense with deep cooling of the gas stream fed to a membrane module, and to carry out gas separation under insignificant cooling of the membrane on the permeate side (down to ?50? C.) For more effective gas separation, permeate is collected in a liquid state. A technical effect of the invention resides in providing a method that makes it possible to efficiently remove high-boiling hydrocarbons (C.sub.3-C.sub.6) from natural gas and associated petroleum gases, as well as to obtain gas mixtures with a constant composition.

Micro- or nano-pores are produced in a membrane for various applications including filtration and sorting functions. Pores with at least one cross-sectional dimension in or near the nano-scale are provided. Device designs and processing allow for the use of thin film disposition and nano-imprinting or nano-molding to produce arrays of nano-pores in membrane materials function ing in applications such as filtration membranes, drug application/control structures, body fluid sampling structures, and sorting membranes. The nano-imprinting or nano-molding approach is utilized to create nano-elements in an organic or inorganic mold material with at least one nano-element cross-sectional dimension in or close to the nano-scale. These nano-elements can be in various shapes including slits, cones, columns, domes, and hemispheres.

Systems comprising a light source, thin membrane immersed in an aqueous solution and a system to direct and focus light from the light source to a spot on the membrane are provided. Methods of thinning and etching a membrane are also provided, as are membranes comprising a nanopore with a Gaussian curve shaped cross-section.

A system for separating, isolating, and concentrating extracellular vesicles (EVs) is provided. The system comprises an ultrafiltration device; an isoporous membrane configured for use in the ultrafiltration device; and a collection container for collecting filtrate from the ultrafiltration device. The ultrafiltration device may be configured to perform diafiltration. The ultrafiltration device may comprise a fixed-volume ultrafiltration device. The ultrafiltration device may comprise a tangential flow filtration device. The system may be scalable.

Disclosed are membranes formed from self-assembling block copolymers, for example, a diblock copolymer of the formula (I): ##STR00001##
wherein R.sup.1R.sup.4, n, and m are as described herein, which find use in preparing nanoporous membranes. Embodiments of the membranes contain the block copolymer that self-assembles into a cylindrical morphology. Also disclosed is a method of preparing such membrane which involves spray coating a polymer solution containing the diblock copolymer to obtain a thin film, followed by annealing the thin film in a solvent vapor and/or soaking in a solvent or mixture of solvents to form a nanoporous membrane.

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.

A method for preparing an asymmetric isoporous membrane with loose cross-section based on a thermally induced phase separation process, and an asymmetric isoporous membrane prepared provided. The prepared isoporous membrane show loose cross-section, high permeability, and high strength, and the fabricating process used recyclable and non-toxic dilutes as the solvents.

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.

This invention is for membranes with precision nanopores (also known as precision nanopore membranes or PNM) offering exceptional permeability and selectivity for separation of gas mixtures. Other applications include microfiltration. The subject PNM has high precision nanopores directly connecting the opposite sides of the membrane, thus avoiding a torturous path fort gas transport of prior art nanoporous membranes. Pores are oriented generally perpendicular to the membrane surface and may occupy a large fraction of membrane surface area. This beneficially offers reduction in membrane thickness and reduced operating pressures. This arrangement offers allow extreme reduction in membrane thickness ensuring high permeability and low driving pressures. The PNM allow for a simplified construction of the separator and a process with much reduced energy consumption compared to current commercial practice.

According to an aspect of the present inventive concept there is provided a method for manufacturing a membrane with through-going pores, the method comprising: controlling starting points for the through-going pores by forming indents on a surface of a semiconductor substrate using a dry-etch process; forming the pores, at locations of the starting points, through the semiconductor substrate using electrochemical etching, wherein the electrochemical etching through the semiconductor substrate selectively starts at the starting points.