Provided is a varnish including 1 to 500 parts by weight of an aromatic tetracarboxylic acid diester (A) represented by General Formula (1), 1 to 450 parts by weight of 2-phenyl-4,4-diaminodiphenyl ether (B), 1 to 100 parts by weight of a 4-(2-phenylethynyl)phthalic acid monoester (C) represented by General Formula (2), and 100 parts by weight of an organic solvent having a boiling point of 150 C. or less at 1 atmosphere or a mixture of two or more of the organic solvents (D). The components (A), (B), and (C) are dissolved in the varnish. ##STR00001##
(In the formula, R.sub.1 is an aromatic tetracarboxylic acid diester residue; R.sub.2 and R.sub.3 are the same or different and are an aliphatic organic group or an aromatic organic group.) ##STR00002##
(In the formula, R.sub.4 and R.sub.5 are a hydrogen atom, an aliphatic organic group, or an aromatic organic group).

A system comprises a build area, a precursor feed system to feed polyimide precursor to the build area, and a laser system comprising a laser device to emit a focused energy beam onto the build area, and a laser actuator to aim the focused energy onto selected target locations of the build area in order to selectively initiate polymerization of at least a portion of the polyimide precursor into a structure including polyimide. A method comprises feeding a polyimide precursor to a build area and selectively directing a focused energy beam to the build area to selectively initiate polymerization of at least a portion of the polyimide precursor into a structure including polyimide.

A resin composition comprises a modified polyimide compound, an epoxy resin, and a solvent. The modified polyimide compound has a chemical structural formula of

##STR00001##

the Ar represents a group selected from a group consisting of phenyl having a chemical structural formula of

##STR00002##

diphenyl ether having a chemical structural formula of

##STR00003##

biphenyl having a chemical structural formula

##STR00004##

hexafluoro-2,2-diphenylpropane having a chemical structural formula of

##STR00005##

benzophenone having a chemical structural formula of

##STR00006##

and diphenyl sulfone having a chemical structural formula of

##STR00007##

and any combination thereof, the epoxy resin and the modified polyimide compound are in a molar ratio of about 0.1:1 to about 1:1. A polyimide film and a method for manufacturing the polyimide film using the resin composition are also provided.

The present invention relates to a polyimide precursor composition, and a polyimide film manufactured using same. According to the present invention, since a polyimide film is manufactured from a mixture of a polyimide precursor having a structure that is advantageous to surface charge accumulation and a polyimide precursor having a structure capable of exhibiting high heat-resistant characteristics, a flexible device using the polyimide film as a substrate can have both improved charge accumulation characteristics caused by an electric field to be generated during the operation of a TFT device and heat high heat-resistant characteristics.

The present invention provides an amic acid ester oligomer having a structure of Formula (1) or (1):

##STR00001## wherein G, P, R, R.sub.x, D, E and m are those as defined in the specification. The present invention also provides a polyimide precursor composition or a photosensitive polyimide precursor composition comprising the amic acid ester oligomer, as well as a polyimide prepared from the composition.

A photosensitive composition is provided. The photosensitive composition includes a composition for forming polyimide, a photoinitiator, a photo cross-linking agent, and a thermal cross-linking agent. The composition for forming polyimide includes a diamine monomer component, an anhydride monomer component, and a polyimide modifier. The diamine monomer component includes a long-chain aliphatic diamine monomer, a carboxylic acid-containing diamine monomer, and a triazole compound. The anhydride monomer component includes a dianhydride monomer and a monoanhydride monomer. The polyimide modifier has a double bond and an epoxy group.

A salt composition includes at least one ammonium carboxylate salt obtained from: (a) at least one aromatic compound comprising 2 anhydride functional groups and/or its carboxylic acid and/or ester derivatives; and (b) one or more aliphatic diamines in which said aliphatic diamine or diamines are chosen from the diamines of formula (I) NH.sub.2RNH.sub.2 with R being a saturated aliphatic divalent hydrocarbon radical, the two amine functional groups of which are separated by 4 to 6 carbon atoms and 1 or 2 hydrogen atoms of the divalent radical of which are replaced by 1 or 2 methyl and/or ethyl groups; and optionally the diamines of formula (II) NH.sub.2RNH.sub.2 with R being a saturated or unsaturated and aliphatic, cycloaliphatic or arylaliphatic divalent hydrocarbon radical, which optionally comprises heteroatoms; and at least one chain-limiting compound chosen from monoamines, monoacids or diacids in the , positions.

The present invention provides an amic acid ester oligomer having a structure of Formula (1) or (1):

##STR00001## wherein G, P, R, R.sub.x, D, E and m are as defined in the specification. The present invention also provides a polyimide precursor composition comprising the amic acid ester oligomer, as well as a polyimide prepared from the composition.

A graphene-based membrane and a method of producing the same are disclosed. The graphene-based membrane may include a graphene-polymer composite, wherein the graphene-polymer composite may consist of an amine functionalized graphene and a polymer containing an anhydride group as a linker for linking the amine functionalized graphene to the polymer. The graphene-based membrane may be constructed of a single-layer. A method may include reacting a polymer containing an anhydride with an amine functionalized graphene in presence of a solvent to form an intermediate product; and thermal imidizing the intermediate product to form a graphene grafted polymer composite for use in fabricating a graphene-based membrane.

Aerogels comprising a hydrophobic polyimide moiety, including hydrophobic polyimide aerogels, as well as methods of manufacture and applications thereof, are generally described. ##STR00001##