Fabrication, Structure, Performance, and Application of Graphene-Based Composite Aerogel.

Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.

Bio-Inspired Design of Bi/Tridirectionally Anisotropic Sliding Superhydrophobic Titanium Alloy Surfaces.

Many biological surfaces with the multi-scale microstructure show obvious anisotropic wetting characteristics, which have many potential applications in microfluidic systems, biomedicine, and biological excitation systems. However, it is still a challenge to accurately prepare a metal microstructured surface with multidirectional anisotropy using a simple but effective method. In this paper, inspired by the microstructures of rice leaves and butterfly wings, wire electrical discharge machining was used to build dual-level (submillimeter/micrometer) periodic groove structures on the surface of titanium alloy, and then a nanometer structure was obtained after alkali-hydrothermal reaction, forming a three-level (submillimeter/micrometer/nanometer) structure. The surface shows the obvious difference of bidirectional superhydrophobic and tridirectional anisotropic sliding after modification, and the special wettability is easily adjusted by changing the spacing and angle of the inclined groove. In addition, the results indicate that the ability of water droplets to spread along parallel and perpendicular directions on the submillimeter groove structure and the different resistances generated by the inclined groove surface are the main reasons for the multi-anisotropic wettability. The research gives insights into the potential applications of metal materials with multidirectional anisotropic wetting properties.

Investigation of the Effects of Polymer Dispersants on Dispersion of GO Nanosheets in Cement Composites and Relative Microstructures/Performances.

This study focused on the uniform distribution of graphene oxide (GO) nanosheets in cement composites and their effect on microstructure and performance. For this, three polymer dispersants with different level of polar groups (weak, mild, and strong) poly(acrylamide-methacrylic acid) (PAM), poly(acrylonitrile-hydroxyethyl acrylate) (PAH), and poly(allylamine-acrylamide) (PAA) were used to form intercalation composites with GO nanosheets. The results indicated that GO nanosheets can exist as individual 1⁻2, 2⁻5, and 3⁻8 layers in GO/PAA, GO/PAH, and GO/PAM intercalation composites, respectively. The few-layered (1⁻2 layers) GO can be uniformly distributed in cement composites and promote the formation of regular-shaped crystals and a compact microstructure. The compressive strengths of the blank, control, GO/PAM, GO/PAH, and GO/PAA cement composites were 55.72, 78.31, 89.75, 116.82, and 128.32 MPa, respectively. Their increase ratios relative to the blank sample were 40.54%, 61.07%, 109.66%, and 130.29%, respectively. Their corresponding flexural strengths were 7.53, 10.85, 12.35, 15.97, and 17.68 MPa, respectively, which correspond to improvements of 44.09%, 64.01%, 112.09%, and 134.79%.