A polyimide film suitable for use in the fabrication of a graphite layer includes a polyimide derived from reaction of diamine monomers with dianhydride monomers, and a foaming agent incorporated in the polyimide. Moreover, a process of fabricating a graphite film includes providing a polyamic acid solution formed by reaction of diamine monomers with dianhydride monomers, incorporating a foaming agent into the polyamic acid solution, forming a polyimide film from the polyamic acid solution, applying a first thermal treatment so that the polyimide film is carbonized to form a carbon film, and applying a second thermal treatment so that the carbon film is converted to a graphite film.

The present invention relates to a method for preparing a nerve conduit containing cells, more particularly to a method for preparing a porous nerve conduit containing cells, having micropores formed in microchannels, wherein the nerve conduit containing cells prepared according to the present invention can be usefully used in in-vitro and in-vivo researches on nerves.

Provided is an oriented multilayer porous film comprising at least one layer comprising: a heat, solvent, and degradation resistant matrix polymer; a plurality of interconnecting pores; and a porosity less than 90%. The film is made by a dry and/or wet method, with its multilayer structure constructed by coextrusion, lamination, and coating. The film of this disclosure finds a wide range of applications as a permselective medium for use in energy harvesting and storage, filtration, separation and purification of gases and fluids, CO.sub.2 and volatile capture, electronics, devices, structural supports, packaging, labeling, printing, clothing, drug delivery systems, bioreactor, and the like. The film is preferably used as a separator of lithium-ion, lithium-sulfur, lithium-air, metal-air, and nonaqueous electrolyte batteries.

A porous polyimide resin film having a high aperture ratio, and a method for producing a porous polyimide film. The method includes removing fine particles from a polyimide resin-fine particle composite film to obtain a porous polyimide resin film by either removing at least a part of a polyimide resin portion of the polyimide resin-fine particle composite film prior to removing the fine particles, or by removing at least a part of the porous polyimide resin film subsequent to removing the fine particles.

The invention relates to the manufacturing of porous polymer membranes by (a) providing pellets comprising a polymer matrix and particles in the ratio 90:10 to 10:90, (b) converting said pellets into a non-porous film by a solvent-free process; (c) removing said particles from said film with an aqueous composition to thereby obtain said membrane. The invention further relates to pellets useful in such manufacturing process as well as porous polymer membranes obtainable or obtained by such manufacturing process as well as textile materials and articles containing such membranes; to the use of such pellets, membranes, and articles.

Provided herein are methods for fabricating a porous polymer material, methods for revealing hidden anti-counterfeiting patterns, chromogenic sensors having hidden anti-counterfeiting patterns, and the like. Chromogenic sensors including porous polymer materials are provided. The chromogenic sensors can reveal hidden patterns such as anti-counterfeiting patterns and the pattern can be re-hidden.