Reduced graphene oxide composites with water soluble copolymers having tailored lower critical solution temperatures and unique tube-like structure

Abstract

Nanohybrids of graphene with water soluble polymer were synthesized using ‘grafting from’ method. GO, prepared by modified Hummers’ method, was first reacted with sodium azide. Alkyne-terminated RAFT-CTA was synthesized by reaction of propargyl alcohol and S-1-dodecyl-S’-(α,α‘-dimethyl-α”-acetic acid) trithiocarbonate. RAFT-CTA was grafted onto the GO sheets by facile click-reaction and subsequently, N-isopropylacrylamide (NIPAM) and N-ethyleacrylamide (NEAM) were polymerized on graphene sheets via RAFT polymerization method. The respective copolymers with different ratios were also prepared. The nanohybrids were characterized by FTIR, XRD, TGA, Raman, SEM, and AFM. Both SEM and AFM clearly showed rod-like structures for rGO-PNEAM. XRD showed a small peak at 2θ = 19.21°, corresponding to d-spacing ≈ 4.6 Å. In addition, the nanohybrids showed a very broad temperature range for the LCST in water between ca. 30 and 70 °C.

Synthesis and Characterization of Graphene Oxide Derivatives via Functionalization Reaction with Hexamethylene Diisocyanate

“…A steady increase in this ratio is observed with increasing FD, from about 1 for GO ( Table 4 , entry 1) to 1.75 for the derivative with the highest FD ( Table 4 , entry 7), which demonstrates a decrease in the structural order, that is, in the size of the in-plane sp 2 domains, owed to the covalent grafting of the HDI chains onto the GO surface. An analogous trend of I D /I G increase has been reported upon covalent functionalization of GO with other organic molecules such as 4-aminobenzenesulfonic acid [ 52 ] or polymers like poly(N-isopropylacrylamide) (PNIPAM) [ 53 ], hinting that the functionalization process results in graphitic domains that are smaller than those of GO.…”

Novel Synthesis of Holey Reduced Graphene Oxide/Polystyrene (HRGO/PS) Nanocomposites by Microwave Irradiation as Anodes for High-Temperature Lithium-Ion Batteries

“…The size of the side group, which matched the hexagonal ordering of the molecular chains, and the other amorphous halo peak at 19.7° were attributed to the van der Waals distance. HRGO/PS (0.1%) showed similar XRD peaks to PS, while the XRD peaks of 1% and 2% HRGO/PS became narrower and more intense, indicating some kind of crystalline structure formation [20]. Mainly, it could be attributed to a relatively intense number of staked graphene layers with the increase in HRGO content.…”

Graphene oxide-based silsesquioxane-crosslinked networks – synthesis and rheological behavior

“…Since the introduction of click chemistry, it has met the need of researchers in different elds of science for a set of powerful, highly reliable, and selective reactions for the rapid synthesis of useful new compounds and combinatorial libraries. 9 Click reactions, and above all Cu(I)-catalyzed Huisgen cycloaddition of azide and alkyne (CuAAC), have made their way into modication of polymers, 10 nanoparticles, 11 carbon nanomaterials, [12][13][14][15][16] and proteins. 17 GO nanosheets were assembled together through an azide-alkyne click reaction to obtain a highly permeable polypropylene membrane, 18 while Lin et al used an azoaromatic crosslinker to connect alkyne-containing GO sheets.…”

“…19 In our recent study, we reported water soluble copolymers having tailored lower critical solution temperatures and a unique tube-like structure, in which a reversible additionfragmentation transfer agent was attached to GO sheets via click chemistry. 14 Polyoligomeric silsesquioxanes (POSS) have a unique cagelike structure with eight organic functionalities, which make it suitable as a core or crosslinking molecule since it is soluble in a wide range of organic solvents. POSS has been used to modify polymers, 20 carbon nanotubes, 21 and nanoparticles.…”