The preparation and characterization of highly conductive carbon inks is described based on nanocomposites that combine a polystyrene-acrylic resin or water-soluble polymers with a hydrophilic graphene/carbon nanotube hybrid. The water-based carbon inks showed high electrical conductivity and could be effectively used in advanced technologies such as gravure printing for printed electronics. Moreover, the conductivity was shown to be increased with a power law of the nanohybrid volume fraction, with an exponent close to that predicted from the percolation theory, indicating a limited impact of the polymer tunneling barrier on the electrical conductivity of such nanocomposites.

In this work, we describe a simple and general procedure for the purification of carbon dots. Following a hydrothermal heating procedure, the reaction mixture usually contains unreacted starting material and by-products alongside the carbon dots, which often appear among otherwise intense photoluminescence. The proposed purification method is based on a solid phase extraction technique, where the reaction mixture is absorbed on porous alumina and the carbon dots are isolated from the by-products and unreacted organics using proper solvents, and are finally recovered from the alumina using a simple extraction.

Following the long-standing experience of the liquid exfoliation of graphite for the production of graphene, a number of analogous van der Waals 2D nanomaterials have been also produced and studied...

A green approach for the functionalization of multiwalled carbon nanotubes (MWNTs) with hydrophilic groups and their use for the development of an ecofriendly conductive ink is described here. A known...

The van der Waals interactions between graphene nanosheets and hydrophobic molecules derived from natural aqueous extracts are indicated as the driving force for high-yield exfoliation of graphite and effective dispersion of graphene produced in pure water. Although it seems paradoxical, the absorption of small hydrophobic organic molecules on large graphene surfaces decreases the hydrophobic character of graphene nanosheets, resulting in significant improvement of graphene dispersibility in water. This fact reveals a totally novel mechanism to produce high-quality graphene nanosheets by liquid exfoliation of graphite in natural aqueous extracts and their dispersion in water at relatively high concentrations. This method is easily scalable, environmentally friendly, and low cost and showed remarkable yields. More importantly, the role of van der Waals interactions in preventing the hydrophobic effect is an unexplored area that could open new pathways for the development of two-dimensional materials or the stabilization of colloidal systems such as polymers, proteins, or other biomolecules.

In this work, we demonstrate a significant improvement in the electrical conductivity of carbon nanostructured thin films, composed of graphene nanosheets and multiwalled carbon nanotubes, by compression/polishing. It is shown that the sheet resistance of compressed thin films of carbon nanostructures and hybrids is remarkably decreased in comparison with that of as-deposited films. The number of the interconnections, the distance between the nanostructures as well as their orientation are highly altered by the compression favoring the electrical conductivity of the compressed samples.

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In the present article, we describe the use of highly fluorescent carbon dots (CDs) for the preparation of an effective water-based carbon dot ink (CD-ink) for gravure printing. Carbon dots were prepared hydrothermally from citrate and triethylenetetramine, and mixed properly with certain resins that are used in gravure inks. The as-produced CD gravure ink was used successfully for printing high quality fluorescent images.