Halogen-free, microporous polyolefin membranes are disclosed herein. The halogen-free, microporous polyolefin membranes can be manufactured using an environmentally friendly manufacturing process that includes extrusion of polymer-plasticizer mixtures followed by sheet formation and extraction of the plasticizer with a halogen-free solvent. The halogen-free solvent has a flashpoint greater than about 23 C. and an initial boiling point at least about 50 C. lower than the flashpoint of the plasticizer. The process can further be a closed loop process in which the halogen-free solvent can be reused.

The present disclosure describes compositions and methods for preparing membrane protein nanosheets and two-dimensional crystals. In particular, the methods employ a solvent. A mixture of a polymer and a membrane protein is solubilized in the solvent, applied to a substrate, and subsequently dried to form the nanosheet or two-dimensional crystal. Applicants have surprisingly found that the membrane proteins maintain their structure when exposed to solvents during the short processing time utilized.

Halogen-free, microporous polyolefin membranes are disclosed herein. The halogen-free, microporous polyolefin membranes can be manufactured using an environmentally friendly manufacturing process that includes extrusion of polymer-plasticizer mixtures followed by sheet formation and extraction of the plasticizer with a halogen-free solvent. The halogen-free solvent has a flashpoint greater than about 23? C. and an initial boiling point at least about 50? C. lower than the flashpoint of the plasticizer. The process can further be a closed loop process in which the halogen-free solvent can be reused.

A liquid-repellent surface is provided where the repellency arises solely from the re-entrant surface structure. The liquid repellent surface is a porous membrane that contains hexagonally packed microcavities, each of which has a narrow opening located on its top. The surface is mechanically robust because the microstructures are interconnected in a continuous manner. A method of preparing the liquid repellent surface is also provided, which involves producing a uniform emulsion containing monodisperse micro-droplets, depositing the emulsion onto a substrate, and solidifying the emulsion-deposit by evaporating the solvent in the continuous phase fluid.

An amphiphilic block copolymer comprises a poly(phenylene ether) block or a poly(phenylene ether) copolymer block and a hydrophilic block or graft. A method of making the amphiphilic block copolymer comprises polymerization of a hydrophilic ethylenically unsaturated monomer in the presence of poly(phenylene ether) or a poly(phenylene ether) copolymer to make the amphiphilic block copolymer. A porous asymmetric membrane comprises a poly(phenylene ether) or poly(phenylene ether) copolymer, and the amphiphilic block copolymer comprising a poly(phenylene ether) block or a poly(phenylene ether) copolymer block, and a hydrophilic block or graft. The porous asymmetric membrane is made by phase-inversion of a dope solution of the poly(phenylene ether) or poly(phenylene ether) copolymer and the amphiphilic block copolymer in a coagulation bath.

A porous membrane is made from a poly(phenylene ether) copolymer containing 10 to 40 mole percent repeat units derived from 2-methyl-6-phenylphenol and 60 to 90 mole percent repeat units derived from 2,6-dimethylphenol; and a block copolymer containing backbone or pendant blocks of poly(C.sub.2-4 alkylene oxide). The porous membrane is made by dissolving the poly(phenylene ether) copolymer in a water-miscible polar aprotic solvent to form a membrane-forming composition; and phase-inverting the membrane forming-composition in a first non-solvent composition to form the porous membrane. A method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, includes coextruding the membrane-forming composition through the annulus, and a first non-solvent composition through the bore, into a second non-solvent composition to form the hollow fiber.

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 1?10.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 zeolite membrane and a preparation method thereof are provided. The method includes: adding an organic binder solution dropwise to zeolite, and thoroughly grinding and stirring; blade-coating a resulting mixture on a substrate at a given thickness; and drying to obtain the zeolite membrane. The preparation of a zeolite membrane does not require a complicated hydrothermal crystal growth process, and the membrane can be prepared directly from natural zeolite or artificial zeolite. A prepared zeolite membrane has the characteristics of simple preparation process, low cost, prominent water permeability, high contaminant rejection rate and high zeolite load. The zeolite membrane, when used for the rejection of contaminants in water, can not only remove macromolecular contaminants in water, but also efficiently remove ammonia nitrogen by way of ion exchange, which is suitable for advanced treatment of wastewater.

Membranes having parallel channels in a surface of the membranes, wherein the channels have side walls having rough surfaces; filters and devices including at least one membrane, and methods of making and using the membranes, are disclosed.

This invention relates to copolymer compositions of poly(vinylidene fluoride-2,3,3,3-tetrafluoropropene) copolymers. The copolymers formed have excellent optical properties, corrosion resistance and electrical properties, with very low haze. Tetrafluoropropene monomer units may be present at from 0.5 to 60 weight percent of the copolymer.