Biobased Janus molecule for the facile preparation of water solutions of few layer graphene sheets

Abstract

A biobased Janus molecule was used to prepare water solutions of nano-stacks made by few layer graphene.The Janus molecule was 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP), a serinol derivative obtained through the neat reaction of 2-amino-1,3-propandiol with 2,5-hexanedione, with atom efficiency of about 85%. SP contains the pyrrole ring, suitable for the interaction with carbon allotropes and hydroxy groups, that can easily interact with polar surroundings. Adducts, with about 14% by mass of SP, were prepared by reacting SP with a high surface area nano-sized graphite (HSAG), with about 35 graphene layers stacked in crystalline domains. Green methods were adopted, such as ball milling (HSAG-SP-M) and heating. Infrared spectra revealed peaks due to both HSAG and SP and additional peaks that could be attributed to the adduct. Both thermal and mechanical reactions left substantially unaltered the order in the graphitic layers and the interlayer distance, as shown by X-ray diffraction patterns. The relative intensity of the G and D band in the Raman spectrum was not modified by the thermal reaction, whereas enhancement of the D peak was observed after ball milling. Stable water solutions of HSAG-SP-M were prepared in a concentration range from 0.1 to 1 mg mL À1 . Centrifugation allowed isolation of adducts with few stacked graphene layers, as revealed by high resolution transmission electron microscopy. An image of the adduct showed an organic layer tightly adhered to the carbon surface. SP appears a suitable molecule for the easy functionalization of carbon allotropes, such as nanostacks of graphene layers, without substantially affecting the bulk crystalline organization and promoting the separation of the aggregates into stacks containing a low/very low number of graphene layers.

Master curves for the sulphur assisted crosslinking reaction of natural rubber in the presence of nano- and nano-structured sp2 carbon allotropes

“…At present, comparative investigation has not been performed. Some of the authors reported Raman spectra of HSAG [47]. In a Raman spectrum, lines D and G, located at 1350 and 1590 cm -1 respectively, indicate the presence of graphitic sp 2 -phase.…”

“…Such findings suggest that sulphur addition occurs on the edges of HSAG graphene layers. Indeed, HSAG is characterized by the relevant presence of electronically perturbed edges [47], which could be suitable sites for the reaction with sulphur. Reaction was also performed between anthracene and sulphur, at 150°C for 12 hours (details are in the experimental part).…”

Facile and sustainable functionalization of graphene layers with pyrrole compounds

“…Serinol pyrrole has been then used as the heterocyclic molecule for the functionalization of sp 2 carbon allotropes [20] and of graphene layers among them. Very high functionalization yield was reported and stable water dispersions of the carbon materials were obtained [21,22]. The high efficiency of the functionalization reaction paved the way to explore the reaction of the carbon allotropes with pyrrole compounds other than serinol pyrrole.…”

“…The polymeric nature of graphene layer with the six atoms aromatic ring as the repeating unit is responsible for such exceptional properties. Hence, main objectives of graphene synthesis [8][9][10][11][12] and functionalization [8,[13][14][15][16][17][18][19][20][21][22][23] are to obtain and preserve such structure.…”

Polyether from a biobased Janus molecule as surfactant for carbon nanotubes

“…In this work, serinol chemoselectivity was exploited [32][33][34], preparing SP through the Paal-Knorr reaction [34,35] of serinol (S) with 2,5-hexanedione (HD), performing the reaction in the absence of solvents and catalysts. SP has been defined as a Janus molecule [36], that means a molecule with two faces and, hence, a dual reactivity. The Roman god Janus, represented (for example in coins) as having two faces in one body, inspired the definition 'Janus' first to describe micro-and nanoparticles with at least two physically or chemically differing surfaces [37,38] and then, more in general, molecules having two faces, a hydrophobic and a hydrophilic one, such as colloids [39] dendritic multiester [40], supermolecular liquid crystals [41], a binding protein for vitamin E [42], block copolymers with (meth)acrylic acid segments [43].…”