Ti₃C₂T_<i>x</i> MXene Nanosheet-Based Probe for Ion Fluorescence and Visual Detection of Ag⁺ in Aqueous Solution and Living Cells

In this study, a naked-eye visible and fluorescence-on Ag+ probe based on two-dimensional material MXene was successfully constructed. This study investigated the π–π and dispersive interactions between MXene and rhodamine-6G, and the reduction and growth of silver ions on the MXene surface. The characterization by transmission electron microscopy and X-ray photoelectron spectroscopy confirmed our conjecture about this process. This probe shows competent highly selective real-time detection of Ag+ in aqueous solution with a 0.035 μM detection limit, which is also capable of Ag+ sensing in living cells. Comparing the fluorescence response of the probe to silver ions in the presence of other metal ions, it is confirmed that the probe has good selectivity to silver ions. In particular, this probe can also be carried out to detect and track Ag+ levels in living cells. The discoveries provide fresh insights into the detection and analysis of silver ions in environmental and biological samples. Meanwhile, this method also provides ideas for constructing MXene-based sensing platforms

Synergistic Effect of Multifunctional Layered Double Hydroxide-Based Hybrids and Modified Phosphagen with an Active Amino Group for Enhancing the Smoke Suppression and Flame Retardancy of Epoxy

To improve the fire hazard of epoxy resin (EP), phosphomolybdate (PMoA), as a classical Keggin cluster, was successfully intercalated into Mg, Al, and Zn layered double hydrotalcite (LDH) by the reconstruction method, and it was denoted as MgAlZn-LDH-PMoA. The structure and morphology of MgAlZn-LDH-PMoA were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. Subsequently, hexa­(4-aminophenoxy)­cyclotriphosphazene (HACP) was prepared and characterized as a high-performance organic flame retardant, which is rich in flame elements phosphorus and nitrogen. The synergistic effects of MgAlZn-LDH-PMoA and HACP on the fire safety of EP composites loaded with different amounts of flame retardant hybrids were studied in detail. Thermogravimetric analysis showed that the char residue of these EP composites increased significantly. Compared with the EP matrix filled with only MgAlZn-LDH-PMoA or HACP, the incorporation of MgAlZn-LDH-PMoA and HACP had a synergistic effect on promoting char formation of EP composites. Particularly, the char yield of EP7 is as high as 29.0%. Furthermore, the synergistic effects of incorporation of MgAlZn-LDH-PMoA with HACP were investigated using the cone calorimeter combustion tests. The results showed that the total heat release and peak heat release rate of the EP composites remarkably declined by 35.2 and 50.9%, respectively, with a loading of 7 wt % hybrid flame retardant. Moreover, the hybrid flame retardants also showed an obvious inhibitory effect on the total smoke production and the release of toxic CO gas. The detailed analysis of the residual char indicated that the main mechanism for improving the flame retardancy and smoke suppression performance is due to both the catalytic carbonization of MgAlZn-LDH-PMoA and phosphoric acid compounds and physical barrier function of the char layer. In addition, the molybdenum oxides produced from [PMo12O40]3– during combustion can not only increase the yield and compactness of the char layer but also reduce the release of CO through a redox reaction, which has important application value to reduce the fire hazard

Fast Self-Healing and Self-Cleaning Anticorrosion Coating Based on Dynamic Reversible Imine and Multiple Hydrogen Bonds

Anticorrosive coatings are extensively investigated as a potential solution to prevent or at least retard metal corrosion occurrence. However, the actual breakthrough is still hampered by the risk of barrier properties loss because of the local failure of the coating. Self-healing coatings can effectively repair microcracks, but outstanding self-healing behavior is always accompanied by poor self-cleaning ability. Herein, we report a series of poly­(dimethylsiloxane) (PDMS) modified with a terephthalic aldehyde (TA)-polyurea (PDMS-TA-PUa) copolymer with a double reversible dynamic bond crosslinking network structure. The PDMS-TA-PUa coating exhibits fast and re-recycled self-healing behavior that heals cracks within 40–50 min at room temperature. The fast self-healing property is attributed to the dynamic nature of the imine bonds and hydrogen bonds in polymer networks. The PDMS-TA-PUa coating also shows great self-cleaning and anticorrosive ability, due to high hydrophobic, low surface energy, and high corrosion potential. Our work gives an insight into the design and preparation of multifunctional coating material with excellent anticorrosion performance, fast self-healing, and self-cleaning properties