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The ability of composite cement materials to resist erosion by chloride ions is a critical factor in evaluating their dependability. This study aims to examine the influence of graphene oxide on the transportation of water molecules and chloride ions in modified cement composites. Molecular dynamics analysis suggests that graphene oxide can effectively bond to the substrate of hydrated calcium silicate gel pores, which forms a stronger confined fluid zone under the action of electrostatic interactions and van der Waals forces. Graphene oxide has negatively charged oxygen functional groups on its surface, and within a certain size range, it becomes more effective at restricting the penetration of water molecules and chloride ions. In addition, chloride solution immersion experiments were performed on graphene oxide modified cement mortar. The results demonstrated that a small quantity of graphene oxide can significantly improve the resistance of modified cement mortar to chloride ion erosion, whereas excessive amounts are detrimental, which aligns with the simulation results. It is hoped that this study will provide valuable insights into the use of graphene oxide nanoparticles in the corrosion protection of cement composites. [ABSTRACT FROM AUTHOR]

Graphene-based materials have been considered as reinforcement for cement-based materials due to its excellent properties. In this paper, the effects of graphene oxide (GO) and graphene nanoplatelets (GNPs) on the mechanical properties and microstructure of cement-based composites are investigated. The results reveal that the incorporation of 0.02 wt% GO and GNPs can enhance the flexural strength by 16.3% and 11.6%, respectively. In addition, GO and GNPs can fill the cracks and form a compacted microstructure in cement mortars. Furthermore, the enhanced mechanism of calcium silicate hydrate composite (C–S–H), which is the main production of cement hydration, is studied by reaction molecular dynamics. The results from simulation show that Young's modulus and tensile strength of C–S–H are enhanced by 32.1% and 23.8% with the incorporation of GO, because the hydrogen-bonds (H-bonds) linkages and Ca2+ near the interface surface play an important role to improve the interface adhesion and transfer more loads between GO and C–S–H. Comparatively, the graphene nanosheet unremarkable enhances the mechanical behaviour of C–S–H composite due to poor binding in the interlayer region. [ABSTRACT FROM AUTHOR]

Owing to their high-specific binding toward targets as well as fast and convenient separation operations, immunomagnetic beads (IMBs) are widely used in the capture and detection of circulating tumor cells (CTCs). To construct the IMBs, surface modifications are generally performed to functionalize the magnetic cores (e.g. Fe3O4 nanoparticles), and the employed surface modification strategies normally influence the structure and functions of the prepared IMBs in return. Different from the existing work, we proposed the use of supramolecular layer-by-layer (LBL) self-assembly strategy to construct the IMBs. In general, owing to the π–π stacking interactions, the polydopamine, graphene oxide and 'molecular glue' γ-oxo-1-pyrenebutyric acid were self-assembled on Fe3O4 nanoparticles sequentially, thereby accomplishing the integration of different functional components onto magnetic cores to prepare the self-assembled supramolecular immunomagnetic beads (ASIMBs). The ASIMBs showed high sensitivity, specificity and good biocompatibility to the model CTCs and low nonspecific adsorption to the negative cells (∼93% for MCF-7 cells and 17% for Jurkat cells). Meanwhile, ASIMBs possessed a remarkable potential to screen the rare MCF-7 cells out of large amounts of interfering Jurkat cells with the capture efficiency of 75–100% or out of mouse whole blood with the capture efficiency of 20–90%. The captured cells can be further recultured directly without any more treatment, which showed huge applicability of the ASIMBs for in vitro detection in clinical practices. [ABSTRACT FROM AUTHOR]

Highlights: Room temperature graphene oxide-assisted assembly of 3D Ti3C2Tx MXene aerogels have been realized by introducing interfacial mediators (amino-propyltriethoxysilane, Mn2+, Fe2+, Zn2+, and Co2+). The methodology not only suppresses the oxidation degradation of Ti3C2Tx, but also generates porous aerogels with a high Ti3C2Tx content (87 wt%) and robustness. As freestanding electrode of the as-prepared Ti3C2Tx-based aerogel with a practical-level mass loading of 12.3 mg cm-2 still delivers an areal capacity of 1.26 mAh cm-2 at a current density of 0.1 A g-1. Low-temperature assembly of MXene nanosheets into three-dimensional (3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process, which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications. Herein, suitable cross-linking agents (amino-propyltriethoxysilane, Mn2+, Fe2+, Zn2+, and Co2+) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide (GO)-assisted assembly of Ti3C2Tx MXene aerogel at room temperature. This elaborate aerogel construction not only suppresses the oxidation degradation of Ti3C2Tx but also generates porous aerogels with a high Ti3C2Tx content (87 wt%) and robustness, thereby guaranteeing the functional accessibility of Ti3C2Tx nanosheets and operational reliability as integrated functional materials. In combination with a further sulfur modification, the Ti3C2Tx aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage. Even at an ultrahigh loading mass of 12.3 mg cm−2, a pronounced areal capacity of 1.26 mAh cm−2 at a current density of 0.1 A g−1 has been achieved, which is of practical significance. This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas. [ABSTRACT FROM AUTHOR]

A 3D monolithic Ti 3 C 2 T x /RGO hybrid hydrogel has been fabricated by a room-temperature GO-assisted gelation method with l -cysteine and Na 2 S, which exhibited excellent performances as self-standing anode for electrochemical sodium-ion storage. [Display omitted] • 3D Ti 3 C 2 T x MXene/RGO hydrogels have been successfully fabricated at room temperature by introducing Na 2 S as the primary reducing agent and l -cysteine as the auxiliary crosslinker. • This room-temperature gelation method not only effectively inhibits the restacking problem of MXene, but also simultaneously avoids the oxidation issue of MXene. • The resulting aerogels with excellent structural robustness can be used as the self-standing electrode, which delivered remarkable specific capacity and excellent cycling stability for sodium-ion storage. Assembling two-dimensional (2D) MXene nanosheets into monolithic three-dimensional (3D) structures is an efficient pathway to transfer the nanoscale properties to practical applications. Nevertheless, the majority of the preparation schemes described in the literature are carried out at relatively high temperatures, which inevitably leads to the notorious high-temperature oxidation issue of MXenes. Preparing MXene-based hydrogels at lower temperatures or even room temperature is of great research importance. In this study, we report a novel and efficient room-temperature gelation method for fabricating 3D macro-porous Ti 3 C 2 T x MXene/reduced graphene oxide (RGO) hybrid hydrogels, using anhydrous sodium sulfide (Na 2 S) as the primary reducing agent and l -cysteine as the auxiliary crosslinker. This room-temperature preparation technique successfully prevents the oxidation issue of MXenes and generates porous aerogels with excellent structural robustness after freeze-drying. As the self-standing anode for sodium-ion storage, the optimized 3D Ti 3 C 2 T x MXene/RGO electrode possesses a specific capacity of 152 mAh/g at 0.1 A/g and good cycling stability with no significant capacity degradation after 500 cycles, which is significantly higher than that of the vacuum-filtered MXene film. This work demonstrates a straightforward room-temperature gelation method for constructing 3D MXene-based hydrogels to avoid the oxidation of MXenes, and casts new insight on the mechanism of the graphene oxide (GO)-assisted gelation. [ABSTRACT FROM AUTHOR]