Abstract: A hydrophilic microporous membrane comprising a thermoplastic resin, having been subjected to hydrophilizing treatment and having a maximum pore size of 0 to 100 nm, wherein when 3 wt % bovine immunoglobulin having a monomer ratio of 80 wt % or more is filtered at a constant pressure of 0.3 MPa, an average permeation rate (liter/m2/h) for 5 minutes from the start of filtration (briefly referred to as globulin permeation rate A) satisfies the following formula (1) and an average permeation rate (liter/m2/h) for 5 minutes from the time point of 55 minutes after the start of filtration (briefly referred to as globulin permeation rate B) satisfies the following formula (2): Globulin permeation rate A>0.0015 ×maximum pore size (nm)2.75 ??(1) Globulin permeation rate B/globulin permeation rate A>0.2 .

Abstract: A vinylidene fluoride resin having a weight-average molecular weight as relatively high as 300,000 or higher is mixed with a plasticizer and good solvent for the vinylidene fluoride resin to obtain a composition. A molten extrudate of the composition in a hollow-fiber membrane state is contacted, on its outer side, with a cooling liquid inert to the vinylidene fluoride resin to thereby cool the extrudate. During the solidification, the vinylidene fluoride resin is moderately and mildly crystallized. Thus, a hollow-fiber porous vinylidene fluoride resin membrane is produced which has a high crystallinity represented by an enthalpy of crystal melting 58 J/g or higher. The hollow-fiber porous membrane obtained is excellent in mechanical strength represented by tensile strength and elongation at break and in chemical resistance. It is effectively used as a water microfiltration membrane.

Abstract: A polymer or blend is described which contains at least one acrylic resin or vinyl resin having at least one ionic or ionizable group, and at least one additional polymer. The polymer has small domain sizes with respect to the acrylic resin or vinyl resin. The polymer preferably has improved conductivity when formed into a film. Preferably, the polymers are useful in a variety of applications including in the formation of a membrane which is useful in batteries and fuel cells and the like. Methods of making the polymer blends are also described.

Abstract: A filter membrane, methods of making such filter membrane and apparatus employing such filter membrane are disclosed, in which the filter membrane is a monolithic polymeric membrane that includes a polymeric filter layer including a micron-scale precision-shaped pores and a polymeric support layer that has a precision-shaped porous support structure for the filter layer. Several methods are disclosed for making such a membrane using micromachining techniques, including lithographic, laser ablation and x-ray treatment techniques. Several filter apparatus employing such a membrane are also disclosed.

Abstract: The present invention provides a highly water permeable hollow fiber membrane type blood purifier for medical use, which is excellent in safety and module-assembling ease and which has a high water permeability suitable for use in therapy of chronic renal failure. The present invention relates to a highly water-permeable hollow fiber type blood purifier comprising hydrophobic polymer hollow fiber membranes each of which contains a hydrophilic polymer, characterized in that the amount of the hydrophilic polymer eluted from the hollow fiber membrane is 10 ppm or less; in that the ratio of the hydrophilic polymer in the outer surface of the hollow fiber membrane is 25 to 50 mass %; in that the burst pressure of the hollow fiber membrane is 0.5 MPa or higher; and in that the coefficient of water permeability of the blood purifier is 150 ml/m2/hr./mmHg or higher.

Abstract: Provided are a nanoporous membrane and a method of fabricating the same. The nanoporous membrane includes a support, and a separation layer including a plurality of nano-sized pores at a density of 1010/cm2 or greater and a matrix. The nanoporous membrane has a high flux and a high selectivity.

Abstract: Process for producing an integrally asymmetrical hydrophobic polyolefinic membrane with a sponge-like, open-pored, microporous support structure and a separation layer with a denser structure, using a thermally induced liquid-liquid phase separation process. A solution of at least one polyolefin is extruded to form a shaped object. The solvent used is one for which the demixing temperature of a solution of 25% by weight of the polyolefin in this solvent is 10 to 70° C. above the solidification temperature. After leaving the die, the shaped object is cooled using a liquid cooling medium that does not dissolve the polymer up to the die temperature, until the phase separation and solidification of the high-polymer-content phase take place.

Abstract: A membrane is provided that is formed from a composition. The composition comprises a polyarylene ether polymer or copolymer comprising a zwitterion; or comprises a polyarylene polymer or copolymer comprising a zwitterion.

Abstract: The present invention is for a polymer/polymer mixed matrix membrane and the use of such membranes in gas separation applications. More specifically, the invention involves the preparation of polymer/polymer mixed matrix membranes incorporating soluble polymers of intrinsic microporosity as microporous fillers. These polymeric fillers of intrinsic microporosity exhibit behavior analogous to that of conventional microporous materials including large and accessible surface areas, interconnected micropores of less than 2 nm in size, as well as high chemical and thermal stability, but, in addition, possess properties of conventional polymers including good solubility and easy processability. Gas separation experiments on these mixed matrix membranes show dramatically enhanced gas separation performance for CO2 removal from natural gas.

Abstract: A hollow-fiber porous membrane comprising a hollow fiber-form porous membrane of vinylidene fluoride resin and having an average pore size Pm of 0.05-0.20 ?m, a maximum pore size Pmax giving a ratio Pmax/Pm of at most 2.0 between the maximum pore size Pmax and the average pore size Pm and a standard deviation of pore size distribution of at most 0.20 ?m based on a pore size distribution according to the half dry/bubble point method (ASTM•F316 and ASTM•E1294) is provided, as a hollow-fiber porous membrane of vinylidene fluoride resin having minute pores with a size (average pore diameter) and a further uniform pore size distribution suitable for water (filtration) treatment.

Abstract: Azidoaryl-substituted cyclooctene monomers and synthesized and used in the preparation of various copolymers. Among these copolymers are those prepared from ring-opening metathesis polymerization of cyclooctene, polyethylene glycol-substituted cyclooctene, and azidoaryl-substituted cyclooctene. These copolymers are useful in the formation of crosslinked films that reduce fouling of water purification membranes.

Abstract: A membrane is provided, which may include a microporous base membrane; and a cross-linkable coating disposed on a surface of the membrane. The coating may include polyvinyl nucleophilic polymer and a urethane or a blocked isocyanate. The coating may be cross-linked. Also provided is a method of making the membrane.

Abstract: A porous fluoropolymer membrane comprising a first surface, a second surface, nodes and free fibrils, wherein one of the first and second surfaces has a greater number of free fibrils per unit area of the surface than the other of the first and second surfaces, is disclosed. A process for preparing porous fluoropolymer membranes is also disclosed, comprising splitting a thicker membrane in a dimension different from, e.g., perpendicular to, its thickness dimension.

Abstract: The present invention provides an asymmetric porous PTFE membrane for a filter having little change over time and conventionally known properties of a porous PTFE molded article such as water permeability resistance, air permeability, sealing properties and electric properties, in which collection efficiency, air permeability and pressure loss are improved. Specifically, the present invention relates to an asymmetric porous PTFE membrane for a filter comprising a dense skin layer and a continuously foamed porous layer, wherein (1) the contact angle of water to the surface of the skin layer is 120 to 140°; and (2) the diffuse reflectance of light is 91 to 94%.

Abstract: The filtration device of the present invention relies on materials and methodologies that achieve the formation of a structural matrix that may later accommodate the addition of other adsorbent materials as opposed to merely binding adsorbent materials together through the use of compression and/or binder materials. The filter device of the present invention relies on (i) a unique method of processing to achieve maximum density of materials, (ii) a polymeric material having a distinct morphology and (iii) a very small micron diameter of the polymeric material to create uniformity. For example, in place of compression to increase density, the materials comprising the filtration device of the present invention are instead vibrated into a mold cavity. Thus, the methodology of the current invention optimizes how all of the materials comprising the filtration device fit together without compaction. The material being processed is vibrated as it is gradually poured into the mold.

Abstract: Water-desalination and/or water purification devices. Alternatively, devices that are implantable in animal bodies, possibly configured as self-inflating spinal disc prostheses. The devices include specified types of water-absorbing solute encapsulated by non-porous, water-permeable polymer membranes having specified properties. Also, methods of using the devices in biomedical applications or water treatment.

Abstract: A porous polyethylene hollow fiber membrane having a pore-size gradient across the inner and outer surfaces thereof is prepared by introducing, during the cooling step of a melt-spun polyethylene hollow fiber, a nitrogen flow and a solvent having a boiling point in the range of 30 to 80° C. to the inner and outer surfaces of the melt-spun hollow fiber, respectively.

Abstract: There is provided a porous membrane of vinylidene fluoride resin which has pores of appropriate size and distribution and also excellent mechanical strength represented by tensile strength and elongation at break and is useful as a microfiltration membrane or a separator for batteries. The porous membrane of vinylidene fluoride resin is characterized by the presence in mixture of a crystalline oriented portion and a crystalline non-oriented portion as confirmed by X-ray diffraction, and is produced by subjecting a melt-extruded composition obtained by mixing a vinylidene fluoride resin having a molecular weight distribution which is appropriately broad and high as a whole with a plasticizer and a good solvent for vinylidene fluoride resin, to cooling for solidification from one surface, extraction of the plasticizer and stretching.

Abstract: The present invention relates to the use of copolymers A containing a) from 50 to 99% by weight of at least one N-vinyllactam or N-vinylamine selected from the group consisting of N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylimidazole, methylated N-vinylimidazole, and N-vinylformamide, and b) from 1 to 50% by weight of at least one monomer selected from the group consisting of b1) C8-C30-alkyl esters of monoethylenically unsaturated C3-C8 carboxylic acids; b2) N—C8-C30-alkyl-substituted amides of monoethylenically unsaturated C3-C8 carboxylic acids; b3) N,N—C8-C30-dialkyl-substituted amides of monoethylenically unsaturated C3-C8 carboxylic acids; b4) vinyl esters of aliphatic C8-C30 carboxylic acids; and b5) C8-C30-alkyl vinyl ethers to produce membranes.

Abstract: The present invention includes a polymeric membrane assembly and method for selective separation of components of a feedstream utilizing the polymeric membrane assembly. The present invention is a novel concept for the manufacture and use of a polymeric membrane assemblies which require the use of fibrous backing materials for fabrication processes utilizing commercial membrane casting equipment. This invention involves as improved membrane assembly configuration and membrane separation process configuration resulting in improved flux and selectivity properties for a given polymeric membrane composition.

Abstract: A hydrophilic body includes a porous membrane with hydrophobic properties. The porous membrane includes at least one of expanded polytetrafluoroethylene, woven polytetrafluoroethylene, and non woven polytetrafluoroethylene. A coating is formed on at least a portion of the porous membrane. The coating has hydrophilic properties and includes at least one of an organofunctional siloxane and a polyether urethane polymer.

Abstract: Novel porous PTFE membranes are described possessing a unique combination of high strength, low flow resistance, and small pore size. Additionally, unique constructions with superior filtration and venting properties incorporating porous PTFE membranes are described.

Abstract: A composition is described wherein a coating is provided on a microporous substrate, such as a low surface energy microporous substrate, which coating provides multiple functionalities to the underlying microporous material, while still maintaining porosity within at least a portion of the microporous substrate.

Abstract: The present invention provides porous media or membranes having a surface coating that includes a first coating of a cross-linked terpolymer and a second coating comprising a copolymer or a terpolymer modified with a hydrophilic or hydrophobic functional group which has a superior combination of properties, including heat stable biomolecule resistant adsorptive properties, resistance to strong alkaline solutions, and low levels of extractable matter.

Abstract: Porous polymeric membranes including Halar (poly (ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fiber or flat sheet, and may include other agents to modify the properties of the membrane, such as the hydrophilic/hydrophobic balance. Leachable agents may also be incorporated into the membranes.

Abstract: The present invention relates to a permeable membrane diaphragm of different layers for electrolytic cell, especially for chloro-alkali electrolytic cell. The diaphragm is asymmetric, which comprises at least two layers: a flow-controlling permeable layer comprising micro-porous fluoropolymer, especially PTFE, and a diffusion-restricting permeable layer comprising porous film, sheet or cloth made of anticorrosive materials, preferably polypropylene. The flow-controlling layer is mounted near the anode, and the diffusion-restricting layer is mounted near the cathode. The mean pore diameter of the diffusion-restricting layer is at least 5 times more than that of the flow-controlling layer and the thickness of the diffusion-restricting layer is at least 1 times more than that of the flow-controlling layer. The pore diameter of said flow-controlling layer ranges from 0.1–2.0 ?m, and its thickness is 0.03–0.2 mm. The pore diameter of said diffusion-restricting layer ranges from 5–50 ?m, and its thickness is 0.

Abstract: The invention relates to a terpolymer of tetrafluoroethylene (TFE) monomer, polyvinylidene fluoride (PVDF) monomer and hexafluoropropylene (HFP) monomer for forming an ultrafiltration or microfiltration membrane, method of forming said membranes, and to the ultrafiltration or microfiltration membranes themselves. The invention also relates to a method of forming a polymeric ultrafiltration or microfiltration membrane including preparing a leachant resistant membrane dope which incorporates a leachable pore forming agent, casting a membrane from the dope and leaching the pore forming agent from the membrane. The invention also relates to a method of preparing a polymeric ultrafiltration or microfiltration membrane of improved structure including the step of adding a nucleating agent to the membrane dope before casting.

Abstract: A defect free semipermeable composite membrane having outstanding integrity and high water permeability is provided. Said composite membrane comprises an inside support layer to provide sufficient mechanical strength, an outside barrier layer to provide selective separation and a middle layer to provide both chemical and physical binding between the support and the barrier layer. Two different methods for making said defect free composite membrane are discovered. These methods have been successfully used to produce high quality coatings and defect free composite membranes, which are independent of chemical composition and physical structure of said support. In the present invention, the ultrasonic sonication is utilized to speed up the phase inversion process of a membrane casting solution, and to produce a composite membrane at a speed higher than that disclosed in the prior art.

Abstract: The filtration device of the present invention relies on materials and methodologies that achieve the formation of a structural matrix that may later accommodate the addition of other adsorbent materials as opposed to merely binding adsorbent materials together through the use of compression and/or binder materials. The filter device of the present invention relies on (i) a unique method of processing to achieve maximum density of materials, (ii) a polymeric material having a distinct morphology and (iii) a very small micron diameter of the polymeric material to create uniformity. For example, in place of compression to increase density, the materials comprising the filtration device of the present invention are instead vibrated into a mold cavity. Thus, the methodology of the current invention optimizes how all of the materials comprising the filtration device fit together without compaction. The material being processed is vibrated as it is gradually poured into the mold.

Abstract: A defect free semipermeable composite membrane having excellent integrity and high water permeability is provided. Said composite membrane comprises an inside support layer to provide sufficient mechanical strength; an outside barrier layer to provide selective separation; and a middle layer to provide both chemical and physical binding between said support and said barrier layer to bond them together. Three different methods for making said defect free composite membrane are discovered. These methods have been successfully utilized to produce high quality coatings and defect free composite membranes, which are independent of chemical composition and physical structure of said support. In the present invention, ultrasonic sonication is discovered to be effective to speed up the phase inversion process of a membrane casting solution, thus allows produce a composite membrane at a speed higher than those disclosed in the prior art.

Abstract: The invention is based on the discovery that certain membranes, which include side chains or molecular “brushes” having, for example, tertiary amino functional groups, can be used as highly effective filters to capture viruses/virus particles from liquids without removal of proteins. New methods based on this discovery include removing viruses from liquids such as blood or plasma, removing viruses from pharmaceuticals, concentrating and/or purifying viruses, e.g., for use in gene therapy, and producing recombinant viruses in new bioreactors. The invention also includes new methods of therapy or adjunct therapy for viral infections, in which a patient's blood or plasma is filtered through the membranes to remove viruses to reduce the viral load. The invention also includes new bioreactors and viral filters containing the membranes.

Abstract: The purpose of the invention is to provide a porous polyolefin membrane consistent with a simple composition that may be characterized by a small pore diameter and a high porosity by simplifying the manufacturing process to facilitate uniform dispersion of the components. Means to achieve the purpose—A porous polyolefin membrane is formed by melting and kneading a specific resin (C) which composition containing a polyolefin resin consisting of a crystalline polypropylene (A) and a propylene-?-olefin copolymer (B), dispersed in said crystalline polypropylene (A), to obtain a film-shaped melt, and forming a membrane from the said melt with specific conditions, followed by stretching of said membrane at least in one direction, which contains continuous pores in the region consisting of said copolymer (B).

Abstract: In one aspect, the invention provides an article consisting essentially of a paper layer including about 10 Wt % to about 40 Wt % of a thermoplastic polymer and an ePTFE membrane laminated to the paper layer. Preferably, the paper layer includes about 10 Wt % to about 30 Wt % of a thermoplastic polymer. More preferably, the paper layer includes about 18 Wt % to about 25 Wt % of a thermoplastic polymer. A paper layer including about 20 Wt % of a thermoplastic polymer is most preferred. In another aspect, the thermoplastic polymer may comprise poly vinyl acetate. In yet another aspect, the invention provides a filter media consisting essentially of a cellulose paper layer including about 20 Wt % poly vinyl acetate binder; and an ePTFE membrane laminated to said cellulose paper layer. In still another aspect, the invention provides a paper layer in which the paper is cellulose paper.

Abstract: The filtration device of the present invention relies on materials and methodologies that achieve the formation of a structural matrix that may later accommodate the addition of other adsorbent materials as opposed to merely binding adsorbent materials together through the use of compression and/or binder materials. The filter device of the present invention relies on (i) a unique method of processing to achieve maximum density of materials, (ii) a polymeric material having a distinct morphology and (iii) a very small micron diameter of the polymeric material to create uniformity. For example, in place of compression to increase density, the materials comprising the filtration device of the present invention are instead vibrated into a mold cavity. Thus, the methodology of the current invention optimizes how all of the materials comprising the filtration device fit together without compaction. The material being processed is vibrated as it is gradually poured into the mold.

Abstract: An organic porous material having selective adsorption ability for boron, characterized in that it has an open cell structure comprising macro pores jointed to one another and, formed within the wall of the macro pore, meso pores having a pore diameter of 0.02 to 200 ?m, has a total pore volume of 1 to 50 ml/g, and contains a compound capable of forming a complex with boric acid introduced through a covalent bonding in an amount of 1 ?mol/g-dry porous material or more. The organic porous material exhibits improved ability for adsorbing boron and also is excellent in stability, and a boron removing module and an ultra-pure water production apparatus using the porous material have extremely high utility.

Abstract: The present invention relates to a novel polymer as binder for producing activated carbon filters. The polymer of the invention is a polyethylene homopolymer and/or copolymer having a melt flow index (MFI 190/15) of from 1.2 g/10 min to 10 g/10 min, a polydispersity Mw/Mn of from 3 to 30, a bulk density of from 0.05 g/cm3 to 0.5 g/cm3 and a particle size from 5 ?m to 300 ?m.

Abstract: This invention provides a process for making microporous membranes from a polymer solution and the membranes therefrom. A thermal assist, such as heating of the polymer solution can be effected subsequent to shaping the solution, such as by forming a film, tube or hollow fiber of the solution under conditions that do not cause phase separation.. In a preferred embodiment, the formed solution is briefly heated to generate a temperature gradient through the body of the formed solution. The polymer in solution then is precipitated to form a microporous structure. The formation of a wide variety of symmetric and asymmetric structures can be obtained using this process. Higher temperatures and/or longer heating times effected during the heating step result in larger pore sizes and different pore gradients in the final membrane product.

Abstract: Solvent-resistant polybenzimidazole membranes, methods of making them and crosslinking them and composite membranes and hollow fiber membrane modules from them are disclosed.

Abstract: Hollow fiber membranes having a skinned surface on one diameter, and a porous surface on the opposite diameter are produced from perfluorinated thermoplastic polymers by extruding a heated solution of the polymer having a low critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally. The hollow fiber membranes are useful as ultrafiltration membranes and as membrane contactors.

Abstract: Hollow fiber membranes having a skinned surface on one diameter, and a porous surface on the opposite diameter arm produced from perfluorinated thermoplastic polymers by extruding a heated solution of the polymer having a lower critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally. The hollow fiber membranes are useful as ultrafiltration membranes and as membrane contactors.

Abstract: A pervaporation process for separating organic liquid mixtures of components having differing polarities, uses an ion exchange membrane which comprises a polymerized alkene including pendant groups of formula SO2N(R)—A—QX where R is H or alkyl, A is alkylene, Q is quaternary ammonium, and X is a negatively-charged counter-ion, the sulfur content of the membrane being in the range 3-10 wt. %.

Abstract: Membranes and methods for making membranes are disclosed. The membranes include a polymeric matrix and a particulate material immobilized within the matrix. The membranes may find particular application in methods and apparatus for removing organic compounds from a biological fluid as part of a pathogen inactivation treatment.

Abstract: Porous hydrophilic membranes comprising a porous inert support on which an ionomer is deposited, said membranes being characterized in that they have a water permeability higher than 1 l/(h.m2.Atm).

Abstract: Membranes and methods for making membranes are disclosed. The membranes include a polymeric matrix and a particulate material immobilized within the matrix. The membranes may find particular application in methods and apparatus for removing organic compounds from a biological fluid as part of a pathogen inactivation treatment.

Abstract: The present invention relates to filtration media having both hydrophobic (water-repellent) properties. The filtration media are produced using a fluorothermoplastic material, such as a terpolymer of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene. The invention also relates to methods of preparing such filtration media using casting solution phase inversion.

Abstract: A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Abstract: The invention is based on the discovery that certain membranes, which include side chains or molecular “brushes” having, for example, tertiary amino functional groups, can be used as highly effective filters to capture viruses/virus particles from liquids without removal of proteins. New methods based on this discovery include removing viruses from liquids such as blood or plasma, removing viruses from pharmaceuticals, concentrating and/or purifying viruses, e.g., for use in gene therapy, and producing recombinant viruses in new bioreactors. The invention also includes new methods of therapy or adjunct therapy for viral infections, in which a patient's blood or plasma is filtered through the membranes to remove viruses to reduce the viral load. The invention also includes new bioreactors and viral filters containing the membranes.

Abstract: A method of treating a membrane comprises the steps of providing a membrane with surfaces that define a plurality of pores extending through the membrane. Providing a dispersion of oleophobic fluoropolymer solids. Stabilizing the dispersion with a stabilizing agent. Diluting the dispersion with a wetting agent. Wetting surfaces which define the pores in the membrane with the diluted and stabilized dispersion. Removing the wetting agent and the stabilizing agent from the membrane. Coalescing the oleophobic fluoropolymer solids of the dispersion on surfaces that define pores in the membrane. A composite membrane comprises a porous membrane having a plurality of interconnecting pores extending through the membrane and made from a material which tends to absorb oils and certain contaminating surfactants. A coating is disposed on surfaces of the nodes and fibrils defining the interconnecting passages in the membrane.

Abstract: The present invention relates to an asymmetric porous polytetrafluoroethylene membrane comprising a dense skin layer and a continuously foamed porous layer, (1) the dense skin layer having a surface roughness Ra of 20 to 165 nm; (2) the dense skin layer having a contact angle for water of 120 to 135°; (3) the porous layer having a maximum pore diameter of 0.03 to 1.0 ?m; and (4) the membrane having a total porosity of 20 to 70%. The asymmetric porous PTFE membrane has an ability to separate each liquid component from a liquid-liquid homogeneous mixture in addition to known properties such as water permeability resistance, gas permeability, sealing property and electric property, wherein change of these properties over time is small.

Abstract: A method for casting-in-place composite and/or non-filled structures which are useful as sorptive or reactive media or for size-based separations. Any particular housing size or configuration can be used, and the inclusion of a large amount of adsorptive particles in polymer is achieved while still maintaining the membrane three dimensional structure. In a first preferred embodiment, the composite structures comprise particles entrapped within a porous polymeric substrate, and are cast in-place into a housing such as a pipette tip, thereby providing an effective platform for micromass handling. With the appropriate selection of particle chemistry, virtually any separation or purification operation can be conducted, including selective bind/elute chromatography operations, on sample mass loads less than 1 microgram in volumes of a few microliters, as well as larger mass loads' and volumes.