In this study, we report an inexpensive, massively scalable, fast, and facile method for preparation of graphene oxide and reduced graphene oxide nanoplatelets. The basic strategy involved the preparation of graphite oxide (GO) from graphite through reaction with benzoyl peroxide (BPO), complete exfoliation of GO into graphene oxide sheets, followed by their in situ reduction to reduced graphene oxide nanoplatelets. The mechanism of graphene oxide producing is mainly the generation of oxygencontaining groups on graphene sheets. In addition, inserted BPO and expansion of CO 2 evolved during reaction will expand the distance between graphite layers, which are also main factors for exfoliation. Thermogravimetric analysis, Raman spectroscopy, and Fourier transform infrared spectroscopy indicated the successful preparation of GO. X-ray diffraction proved the mechanism of intercalation and exfoliation of graphite. Transmission electron microscopy and atomic force microscopy were used to demonstrate the structure of produced graphene oxide and reduced graphene oxide nanoplatelets.

Between the sheets: Polystyrene–polyacrylamide copolymer is covalently grafted onto graphene sheets by in situ living free‐radical polymerization to give “amphiphilic” graphene nanoplatelets. The block copolymer disperses graphene nanoplatelets in a polar solvent (water; see picture, A versus C) and also stabilizes them in a nonpolar solvent (xylene; B versus D).

Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5:2 THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5:2 THz are 0.68 and 0.74, respectively.

The integration of structure and function for tissue engineering scaffolds is of great importance in mimicking native bone tissue. However, the complexity of hierarchical structures, the requirement for mechanical properties, and the diversity of bone resident cells are the major challenges in constructing biomimetic bone tissue engineering scaffolds. Herein, a Haversian bone–mimicking scaffold with integrated hierarchical Haversian bone structure was successfully prepared via digital laser processing (DLP)–based 3D printing. The compressive strength and porosity of scaffolds could be well controlled by altering the parameters of the Haversian bone–mimicking structure. The Haversian bone–mimicking scaffolds showed great potential for multicellular delivery by inducing osteogenic, angiogenic, and neurogenic differentiation in vitro and accelerated the ingrowth of blood vessels and new bone formation in vivo. The work offers a new strategy for designing structured and functionalized biomaterials through mimicking native complex bone tissue for tissue regeneration.