VDF-co-(TFE or TrFE) polymers having a molecular weight of at least about 1,000,000 g/mol and a melt temperature less than about 240° C. The VDF copolymer contains at least about 50 mol % VDF monomer and may include an amount of at least one other monomer. The VDF copolymer may be used to form a membrane that has a node and fibril structure. The membrane has a percent porosity of at least 25%. A VDF-co-(TFE or TrFE) polymer membrane may be formed by lubricating the VDF copolymer, subjecting the lubricated polymer to pressure at a temperature below the melting point of the VDF copolymer to form a preform material, and expanding the preform material at a temperature below the melting temperature of the VDF copolymer. Dense VDF copolymer articles, filled VDF copolymer membranes, and VDF copolymer fibers are also provided.

VDF-co-(TFE or TrFE) polymers having a molecular weight of at least about 1,000,000 g/mol and a melt temperature less than about 240° C. The VDF copolymer contains at least about 50 mol % VDF monomer and may include an amount of at least one other monomer. The VDF copolymer may be used to form a membrane that has a node and fibril structure. The membrane has a percent porosity of at least 25%. A VDF-co-(TFE or TrFE) polymer membrane may be formed by lubricating the VDF copolymer, subjecting the lubricated polymer to pressure at a temperature below the melting point of the VDF copolymer to form a preform material, and expanding the preform material at a temperature below the melting temperature of the VDF copolymer. Dense VDF copolymer articles, filled VDF copolymer membranes, and VDF copolymer fibers are also provided.

An object of the present invention is to provide a porous hollow-fiber membrane having high strength while maintaining high pure-water permeation performance. A porous hollow-fiber membrane of the present invention is a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane, and a molecular chain of the fluororesin-based polymer is oriented in the longitudinal direction of the porous hollow-fiber membrane.

A nanocomposite blend membrane and fabrication methods for making the nanocomposite membrane are disclosed. The nanocomposite blend membrane can be utilized in fuel cells. The nanocomposite blend membrane may include a blend polymer with a first sulfonated polymer and a second sulfonated polymer, as well as sulfonated tungsten trioxide (WO.sub.3) nanoparticles.

A steam permselective membrane containing a crosslinked hydrophilic polymer is provided. The steam permselective membrane may further contain at least one alkali metal compound selected from the group consisting of a cesium compound, a potassium compound and a rubidium compound.

A steam permselective membrane containing a crosslinked hydrophilic polymer is provided. The steam permselective membrane may further contain at least one alkali metal compound selected from the group consisting of a cesium compound, a potassium compound and a rubidium compound.

Water permeable coated substrates and filtration membranes are provided comprising: (a) a porous substrate; (b) an optional primer layer applied to a substrate surface (a), wherein the primer layer comprises silica and/or an organometallic compound; (c) a superhydrophilic coating layer applied to the porous substrate (a), or the primer layer (b), wherein the superhydrophilic layer comprises a superhydrophilic polymer or silicate; and (d)

an optional tie layer applied to the superhydrophilic coating layer (c), wherein the tie layer comprises silica and/or an organometallic compound. The water permeable coated substrates and filtration membranes may further include (e) an oleophobic coating layer applied to the superhydrophilic coating layer (c), or the tie layer (d), wherein the oleophobic coating layer comprises a fluoropolymer having reactive functional groups. Each layer of the coated substrate is covalently bonded to adjacent layers. Methods of separating an oil-in-water emulsion are also disclosed.

Water permeable coated substrates and filtration membranes are provided comprising: (a) a porous substrate; (b) an optional primer layer applied to a substrate surface (a), wherein the primer layer comprises silica and/or an organometallic compound; (c) a superhydrophilic coating layer applied to the porous substrate (a), or the primer layer (b), wherein the superhydrophilic layer comprises a superhydrophilic polymer or silicate; and (d)

an optional tie layer applied to the superhydrophilic coating layer (c), wherein the tie layer comprises silica and/or an organometallic compound. The water permeable coated substrates and filtration membranes may further include (e) an oleophobic coating layer applied to the superhydrophilic coating layer (c), or the tie layer (d), wherein the oleophobic coating layer comprises a fluoropolymer having reactive functional groups. Each layer of the coated substrate is covalently bonded to adjacent layers. Methods of separating an oil-in-water emulsion are also disclosed.

A filtering device is for obtaining a chemical liquid by purifying a liquid to be purified, and has an inlet portion, an outlet portion, a filter A, at least one filter B different from the filter A, and a flow path which includes the filter A and the filter B arranged in series between the inlet portion and the outlet portion and extends from the inlet portion to the outlet portion, in which the filter A includes at least one kind of porous membrane selected from the group consisting of a first porous membrane having a porous base material made of polytetrafluoroethylene and a non-crosslinked coating which is formed to cover the porous base material and contains a perfluorosulfonic acid polymer and a second porous membrane containing polytetrafluoroethylene blended with a perfluorosulfonic acid polymer.

A preparation method of composite materials having ion exchange function is provided. The method comprises the following steps: adding a trace of strong protonic acid and/or Lewis acid as a catalyst into the material during compounding, to allow nitrile groups of at least one nitrile group-containing ion exchange resin and nitrile groups of functional monomers grafted on the porous fluoropolymer membrane to form a triazine ring crosslinked structure.