▎ 摘　　要

NOVELTY - Dry graphene powder composition comprises pristine graphene flakes, where the pristine graphene flakes are non-covalently functionalized with polymeric amphiphilic molecules, and the dry graphene powder composition is capable of dispersion in aqueous or alcoholic media, or in water, or in an alcohol/water mixture, to form a stable homogeneous dispersion of pristine graphene in the absence of free dispersants or stabilizers. The polymeric amphiphilic molecules comprise (a) terminal aromatic moiety or conjugated double-bond moiety for non-covalently functionalizing the pristine graphene flakes via pi - pi stacking adsorption, and (b) terminal and optionally ionizable polar moiety for imparting hydrophilicity to the pristine graphene flakes. The polymeric amphiphilic molecules are aromatic molecules (I). USE - The dry graphene powder, stable homogeneous dispersion, or the slurry or paste is useful in graphene ink used in two-dimensional (2D) or three-dimensional (3D) printing: to produce a 3D or 2D printed article including conductive circuits, electrode materials, and electrocatalyst layers/supports; and to produce pristine graphene fibers, or to fabricate a nanocomposite material incorporating pristine graphene (all claimed). ADVANTAGE - The 3D or 2D printed article has 350 Omega /sq conductivity measured as sheet resistance, preferably 35 Omega /sq or 30 Omega /sq without the need for carrying out thermal annealing. The dry graphene powder: is stable, and water-redispersible, alcohol-redispersible or water/alcohol redispersible; and provides feasible and cost-effective strategies for large-scale fabrication of modern electronics. DETAILED DESCRIPTION - Dry graphene powder composition comprises pristine graphene flakes, where the pristine graphene flakes are non-covalently functionalized with polymeric amphiphilic molecules, and the dry graphene powder composition is capable of dispersion in aqueous or alcoholic media, or in water, or in an alcohol/water mixture, to form a stable homogeneous dispersion of pristine graphene in the absence of free dispersants or stabilizers. The polymeric amphiphilic molecules comprise (a) terminal aromatic moiety or conjugated double-bond moiety for non-covalently functionalizing the pristine graphene flakes via pi - pi stacking adsorption, and (b) terminal and optionally ionizable polar moiety for imparting hydrophilicity to the pristine graphene flakes. The polymeric amphiphilic molecules are aromatic molecules of formula ((-Ar1(L1-P1)-)n) (I). Ar1 = aromatic moiety; P1 = optionally ionizable polar moiety or its salt; n = 20-350; and L1 = linker comprising bond, 1-20C alkanediyl, 1-20C heteroalkanediyl, 1-20C alkenediyl, 1-20C heteroalkenediyl, 1-20C alkynediyl or 1-20C heteroalkynediyl. INDEPENDENT CLAIMS are also included for: (1) preparing the dry graphene powder composition; (2) a stable homogenous dispersion comprising the dry graphene powder composition, redispersed in aqueous or alcoholic media where the media is free from dispersants or stabilizers; (3) a slurry or paste comprising the dry graphene powder composition in aqueous or alcoholic media; (4) graphene ink for use in two-dimensional (2D) or three-dimensional (3D) printing comprising the dry graphene powder composition, the stable homogeneous dispersion, or the slurry or paste; (5) printing the 2D article, comprising printing the stable homogeneous dispersion, the slurry or paste or the graphene ink onto a 2D substrate and then drying, optionally where the 2D substrate is a flexible substrate and/or the 2D article is a flexible conductive circuit; (6) printing the 3D article, comprising printing the stable homogeneous dispersion, the slurry or paste or the graphene ink into a coagulant bath containing a suitable coagulant, followed by removal from the bath, freezing and then drying, optionally where the coagulant bath contains 1-10 wt.% carboxymethylcellulose sodium salt (CMC) solution as the coagulant, and/or the coagulant bath contains 5 wt.% CMC solution as the coagulant, and/or freezing is carried out by immersing the 3D printed article in liquid nitrogen, and/or drying is carried out by lyophilization; (7) pristine graphene fibers manufactured from, or a nanocomposite material incorporating pristine graphene fabricated with the dry graphene powder, the stable homogeneous dispersion, the slurry or paste or the graphene ink; (8) wet-spinning pristine graphene fibers, comprising injecting the stable homogeneous dispersion, the slurry or paste, or the graphene ink into a coagulant bath containing a suitable coagulant, where the stable homogeneous dispersion comprises the dry graphene powder composition dispersed in aqueous medium, preferably aqueous poly(1-vinyl-3-ethylimidazolium bromide) solution and/or the stable homogeneous dispersion comprises poly-(2-(3-thienyl)ethyloxy-4-butylsulfonate)sodium salt (PTEBS) functionalized pristine graphene powder, dispersed at 5 mg/ml in aqueous poly(1-vinyl-3-ethylimidazolium bromide) solution (1 wt.%); and (9) fabricating the nanocomposite material incorporating pristine graphene, comprising forming a stable homogeneous dispersion, and a solubilized matrix material, and inducing self assembly of the pristine graphene with the matrix material, where the matrix material is capable of forming a hydrogel, a composite or aerogel, the matrix material is a protein, a peptide, a polymer, a biopolymer or an oligomer, the matrix material is silk fibroin, the stable homogeneous dispersion is formed by mixing graphene powder dispersed in aqueous media with an aqueous solution of matrix material, the stable homogeneous dispersion is formed by mixing graphene powder dispersed in water with an aqueous solution of silk fibroin, the stable homogeneous dispersion is formed by mixing graphene powder dispersed in water (at 2 mg/ml) with an aqueous solution of silk fibroin (at 30 wt.%), and/or the self-assembly is induced chemically or physically or electrically, the self-assembly is induced chemically by adding a crosslinking agent or adjusting the pH or electrolyte concentration of the homogeneous dispersion, the self-assembly is induced by evaporating the solvent of the homogeneous dispersion, the self-assembly is induced physically by sonication or the self-assembly is induced electrically by applying a direct current, the self-assembly is induced thermally by heating and/or cooling or the self-assembly is induced mechanically by shearing.