Three-dimensional (3D) structures of graphene have attracted extensive interest for their practical applications, such as supercapacitors and catalyst supports. Self-assembly is a typical technique to fabricate macroscopic graphene materials integrated with various superior properties. However, an efficient and environmentally-friendly strategy is still needed. In this paper, we report a green and mild method for the synthesis of 3D architectures of graphene. This proposed method is based on the chemical reduction of graphene oxide (GO) with the aid of a range of natural phenolic acids and in situ self-assembly of graphene sheets via π–π interactions. The obtained monolithic graphene exhibits low density, super hydrophobicity, high porosity, excellent mechanical strength and electrical conductivity. These multifunctional products can be used as adsorbents for removal of oils, organic solvents and dyes from contaminated water, as well as electrode materials for supercapacitors.

Aramid macroscale fibers, also called Kevlar fibers, exhibit extremely high mechanical performance. Previous studies have demonstrated that bulk aramid macroscale fibers can be effectively split into aramid nanofibers (ANFs) by dissolution in dimethylsulfoxide (DMSO) in the presence of potassium hydroxide (KOH). In this paper, we first introduced the ANFs into the structure of graphene nanosheets through non-covalent functionalization through π–π stacking interactions. Aramid nanofiber-functionalized graphene sheets (ANFGS) were successfully obtained by adding the graphene oxide (GO)/DMSO dispersion into the ANFs/DMSO solution followed by reduction with hydrazine hydrate. The ANFGS, with ANFs absorbed on the surface of the graphene nanosheets, can be easily exfoliated and dispersed in N-methyl-2-pyrrolidone (NMP). Through a combination of these two ultra-strong materials, ANFs and graphene nanosheets (GS), the resultant ANFGS can act as novel nanofillers for polymer reinforcement. We used the ANFGS as an additive for reinforcing the mechanical properties of poly(methyl methacrylate) (PMMA). With a loading of 0.7 wt% of the ANFGS, the tensile strength and Young's modulus of the ANFGS/PMMA composite film approached 63.2 MPa and 3.42 GPa, which are increases of ∼84.5% and ∼70.6%, respectively. The thermal stabilities of ANFGS/PMMA composite films were improved by the addition of ANFGS. Additionally, the transparencies of the ANFGS/PMMA composite films have a degree of UV-shielding due to the ultraviolet light absorption of the ANFs in the ANFGS.

Two dimensional nanomaterials are of great significance in a wide range of applications due to their high surface area and novel properties. Here we offer a simple and large-scale method to prepare graphene and its inorganic analogues (MoS₂, WS₂ and boron nitride) by the sonication of their bulk materials in an aqueous solution of gelatin. The concentrations of the obtained stable dispersions were up to 0.6, 0.8, 0.9 and 1.4 mg mL⁻¹ for graphene, MoS₂, WS₂ and boron nitride, respectively. Transmission electron microscopy strongly suggests that the materials have been exfoliated into few- or mono-layer thin sheets. Specifically, graphene and MoS₂ dispersion have been directly employed to fabricate gelatin–graphene composites. Scanning electron microscope images show that graphene flakes were homogeneously dispersed in the composites. The tensile test results show that the mechanical properties of gelatin films have been remarkably improved by graphene rather than MoS₂.

Gum arabic (GA), a natural polymer, is extensively used in food, drug, confectionery and soft drinks processing. In this paper, we present a green and facile approach for preparing graphene–Ag nanohybrids assisted by GA. In brief, GA functionalized graphene sheets (GA-G) were prepared by directly exfoliating graphite flakes in gum arabic (GA) aqueous solution with sonication. The yield of graphene exfoliation was systemically studied by varying the initial graphite concentration, GA concentration and sonication time. Furthermore, the GA functionalized graphene sheets–Ag nanoparticle hybrids (Ag/GA-G) were fabricated by adding AgNO₃ aqueous solution into the GA-G water dispersion. The silver ions were directly reduced and immobilized on the surface of the GA-G nanosheets by GA. The Ag/GA-G hybrid materials can be used as suitable substrates of SERS for the detection of 4-aminothiophenol (4-ATP) at a detectable level of a concentration of 10⁻⁶ M in aqueous environments.