The present invention discloses a polyimide material, a preparation method thereof, and an electrochromic device, wherein the polyimide material has a polyhedral oligomeric silsesquioxane (POSS) as an end capping group. The present invention has the beneficial effects that the polyimide material, the preparation method thereof, and the electrochromic device of the present invention use an oligoaniline and a fluorescent triphenylamine fragments as raw materials to prepare a polyamic acid solution, and then introducing the polyhedral oligomeric silsesquioxane (POSS) as the end capping group of the polyimide material to give an electrochromic ability and stable electroluminescence to the polyimide material, which provides directional guidance for subsequent fluorescent displays and electrochromic devices.

Disclosed is a composition comprising a silicon-containing compound represented by the general formula (1) mentioned in the description of the present application, at least one compound of the general formula (2-1) or (2-2) in which m is an integer of 3 or greater mentioned in the description of the present application, and optionally a compound represented by the general formula (3). The total amount of the silicon-containing compound of the general formula (2-1) or (2-2) in which m is an integer of 3 or greater is more than 0 ppm and 46,000 ppm or less based on the total weight of the silicon-containing compounds of the general formulas (1), (2-1), (2-2), and (3). The composition is used for producing a polyimide precursor obtained by copolymerizing a silicon-containing compound, tetracarboxylic dianhydride, and diamine.

The present disclosure discloses an LED filament, comprising a plurality of LED chips; at least two electrodes, each of the at least two electrodes is connected to at least one of the plurality of LED chips; and a light conversion layer comprising a top layer and a base layer, coated on at least two sides of the at least two electrodes, and a portion of the at least two electrodes is exposed by the light conversion layer, where the top layer and the base layer are located at two sides of the plurality of LED chips, respectively, wherein the base layer comprising an organosilicon-modified polyimide, a thermal curing agent and fluorescent powders. The present disclosure further discloses an LED light bulb. The base layer of the present disclosure has superior transmittance, heat resistance and mechanical strength, and is suitable for producing a flexible LED filament.

A method of removing a photoresist, a laminate, a method of forming a metallic pattern, a polyimide resin, and a stripper are provided. The method of removing the photoresist includes forming a release layer on a substrate, the release layer having a first surface and a second surface opposite to each other, wherein the first surface of the release layer is in contact with the substrate; forming a photoresist layer on the second surface of the release layer; and removing the release layer and the photoresist layer. The release layer is formed by a polyimide resin. The polyimide resin is obtained by performing a polymerization of tetracarboxylic dianhydrides, diamines, and phenolamines. The diamines include hydroxyfluorinated diamines, benzoic acid diamines, and aminotetramethyldisiloxanes.

Provided is a detachable layer-forming composition which, for example, contains an organic solvent and a polyamic acid, both ends of which are derived from a diamine and sealed with an aromatic dicarboxylic acid, such as the polyamic acid represented by this formula.

##STR00001##

In the formula, X represents a tetravalent aromatic group, Y represents a divalent aromatic group, R.sup.1-R.sup.4 each independently represent a hydrogen atom, a C1-10 alkyl group, or a C6-20 aryl group, and m is a natural number.

The present invention provides a polyimide precursor solution which can enhance the uniformity of a polyimide film and also improve the efficiency of processes by improving liquid curl in a coating process of the polyimide precursor solution. In addition, since polyimide according to the present invention has excellent transparency, heat resistance, mechanical strength and flexibility by comprising a specific structure, the polyimide may be used in various fields, such as substrates for devices, cover substrates for displays, optical films, integrated circuit (IC) packages, adhesive films, flexible printed circuits (FPCs), tapes, touch panels, protective films for optical discs, etc.

An object of the invention is to provide a cured film which is high in sensitivity, capable of forming a pattern in a low-taper shape after development, capable of the change in pattern opening width between before and after thermal curing, an excellent in light-blocking property, and a negative photosensitive resin composition that forms the film. The negative photosensitive resin composition contains an (A) alkali-soluble resin, a (C1) photo initiator, and a (Da) black colorant, where the (A) alkali-soluble resin contains a (A1) first resin including one or more selected from the group consisting of a (A1-1) polyimide, a (A1-2) polyimide precursor, a (A1-3) polybenzoxazole, and a (A1-4) polybenzoxazole precursor, and has a structural unit having a fluorine atom at a specific ratio, and the (C1) photo initiator contains an (C1-1) oxime ester-based photo initiator that has a specific structure.

The resin composition of the present invention contains a maleimide compound (A) represented by the following formula (1); and a cyanate compound (B). ##STR00001## wherein R each independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, a proportion of R representing a methyl group, among all R, is 50 mol % or more, and n represents an integer of 0 to 2.

The present invention provides a photosensitive polyimide composition comprising a polyimide resin having a structural unit represented by the formula (1) and a structural unit represented by the formula (2), a quinonediazide sulfonate, a thermal curing agent, and a thermal acid generator. ##STR00001## In the formulas (1) and (2), n is an integer of 10 to 600, Ar.sub.1 is a tetravalent organic group; Ar.sub.2 is a divalent to tetravalent organic group; Ar.sub.3 is a divalent aromatic group; and R.sub.1 is an OH group or a COOH group. The present invention also provides a photoresist film made of the above-mentioned photosensitive polyimide composition.

The present invention relates to a hydrophilic polyimide including at least one type of building blocks [A-B] and [A-C], and represented by the formula -[A-B].sub.n-[A-C].sub.m— (I), wherein: the n-bracketed building blocks and the m-bracketed building blocks are randomly distributed over the polyimide chain; repeat unit A results from a monomer comprising two carboxylic anhydride moieties, repeat unit B is hydrophilic and results from a first hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines, and repeat unit C is hydrophilic and results from a second hydrophilic monomer comprising two primary amine moieties and at least one further hydrophilic moiety different from the primary amines; wherein: n and m represent independently an integer from 0 to about 1000; wherein n+m is an integer from about 10 to about 1000.

The present invention also relates to a porous membrane comprising the same, a method of producing the hydrophilic polyimide and the porous membrane, a liquid phase separation system comprising the porous membrane, and a liquid phase separation method.