MXenes, two-dimensional transition metal carbides and nitrides, show great potential in various applications. However, traditional synthesis methods often involve toxic fluorine-containing etchants, limiting large-scale production. This study introduces a novel, environmentally friendly approach for synthesizing Ti 3 C 2 T x MXene nanosheets using stone grinding-assisted exfoliation and mild alkaline etching at 80°C. The synthesized MXene nanosheets exhibited high aspect ratios with transverse dimensions mostly on the micrometer scale and a thickness of approximately 3 nm, corresponding to one to two layers of Ti 3 C 2 . MXene/polyvinyl alcohol (PVA) composite membranes were fabricated to demonstrate practical applications. The composite membrane containing 1 wt% MXene achieved a 99.9% UV shielding rate while maintaining 67% visible light transmittance. Furthermore, it significantly enhanced PLA's UV resistance, with protected samples retaining 98.1% tensile strength after 48 hours of UV exposure, compared with 47.8% for unprotected PLA. This fluorine-free synthesis method addresses environmental concerns and enables large-scale MXene production for advanced UV protection applications. Highlights Ti 3 C 2 T x MXene is made via stone grinding and alkaline etching. MXene nanosheets are produced in the micron range and are 1–2 layers thick. The fluorine-free synthesis enables green, large-scale production of MXene. MXene/PVA films show 99.99% UV shielding with 67% visible light transmittance. MXene/PVA coating improves PLA's UV resistance, keeping 98.1% of tensile strength.
Weiqing Wu,Luchan Lin,Yifan Hu,Junde Ji,Xinde Zuo,Yiwei Yu,Qianyi Zhang,Zhengjie Cai,Zhuguo Li
Ultralong graphene nanoribbons (GNRs) have drawn much attention in the field of high performance nanoelectronics. In this work, a mask-free ultrafast laser lithography method is demonstrated for the mass production of ultralong GNR arrays with an intact carbon network. The longest GNR reaches ∼42 μm with a width of ∼400 nm. The orientation of the as-received GNR arrays is always parallel to the incident laser polarization direction. Original carbon network structures of remaining GNRs are preserved, which are ascribed to the precise energy injection and selective nanoablation in graphene flakes. The formation of large-scale GNR arrays is mainly determined by the interference between the incident laser and the stimulated transverse electric mode surface plasmon (TE-SPs) wave. The excitation of the TE-SPs wave prefers to be triggered at the geometrical fluctuations on ablated graphene surfaces as well as the interface with a large discrepancy of dielectric permittivity (e.g., graphene and SiO2). With the initial generation of the nanoablated groove on the surface, the interference between TE-SPs waves and incident laser beams further extends to the far end with periodic intervals, which results in the continuous formation of GNRs. This ultrafast laser-induced periodic lithography may provide an alternative for ultralong and high aspect ratio GNR array fabrication, which is promising in high performance nanodevice development.
To enhance the discharge energy density ( U e ) of polyvinylidene fluoride (PVDF), two-dimensional (2D) titania nanosheets (TNSs) with high aspect ratio were introduced into PVDF. The results show that the TNSs are uniformly dispersed in matrix and the existence of matrix-filler interface is confirmed by small angle X-ray scattering. Introducing of high aspect ratio TNSs is beneficial to enhance the concentration of polar β-phase and interfacial polarization, which can improve the permittivity ( ε r ) of nanocomposites. Meanwhile, the shape of 2D TNSs plays an important role in enhancement of breakdown strength ( E b ). The ε r and E b of the nanocomposites are two significant factors of their high energy storage performance. Therefore, the U e increases to 0.32 J/cm 3 , which is 28% higher than that of pure PVDF (~0.25 J/cm 3 ). The energy efficiency of this typical nanocomposite is similar as that of pure PVDF (~90%). This work might provide a method of fabricating promising energy storage dielectric materials.
危险品化学品经营许可证（带存储）