Robust MXene Nanosheet-Based Electromagnetic Interference Shielding Membrane with Cation–π Interactions

Electromagnetic interference (EMI) shielding is vital for electronic device reliability and combating electromagnetic wave (EMW) pollution. In this research, we employed a vacuum-assisted filtration method to fabricate MXene membranes and achieved the construction of robust PAA/MXene hybrid membranes by incorporating a polyamic acid (PAA) adhesive containing imidazole rings through cation–π interactions. The integration of PAA led to a reduction in internal pores and the thickness of the MXene membrane, mainly attributed to the reinforcing cation–π interactions that enhance the interlayer forces among the MXene nanosheets. This integration substantially enhances the tensile strength of MXene membranes and concurrently induces alterations in their fracture behavior. Adding a small amount of PAA greatly increased conductivity in the PAA/MXene hybrid membrane, but excessive amounts resulted in a severe decline. When PAA content remained below 2 wt % of MXene nanosheets, the EMI SET of the PAA/MXene hybrid membrane exhibited minimal fluctuations, consistently exceeding 60 dB. The EMI shielding mechanism of the PAA/MXene hybrid membrane primarily relied on reflection, with reflected electromagnetic waves accounting for over 60% of the incident EMWs. The utilization of cation–π interactions in this approach significantly enhances the interface of MXene nanosheets, thereby holding immense potential for the advanced modification of MXene materials

Robust MXene Nanosheet-Based Electromagnetic Interference Shielding Membrane with Cation–π Interactions

Electromagnetic interference (EMI) shielding is vital for electronic device reliability and combating electromagnetic wave (EMW) pollution. In this research, we employed a vacuum-assisted filtration method to fabricate MXene membranes and achieved the construction of robust PAA/MXene hybrid membranes by incorporating a polyamic acid (PAA) adhesive containing imidazole rings through cation–π interactions. The integration of PAA led to a reduction in internal pores and the thickness of the MXene membrane, mainly attributed to the reinforcing cation–π interactions that enhance the interlayer forces among the MXene nanosheets. This integration substantially enhances the tensile strength of MXene membranes and concurrently induces alterations in their fracture behavior. Adding a small amount of PAA greatly increased conductivity in the PAA/MXene hybrid membrane, but excessive amounts resulted in a severe decline. When PAA content remained below 2 wt % of MXene nanosheets, the EMI SET of the PAA/MXene hybrid membrane exhibited minimal fluctuations, consistently exceeding 60 dB. The EMI shielding mechanism of the PAA/MXene hybrid membrane primarily relied on reflection, with reflected electromagnetic waves accounting for over 60% of the incident EMWs. The utilization of cation–π interactions in this approach significantly enhances the interface of MXene nanosheets, thereby holding immense potential for the advanced modification of MXene materials

Facile Fabrication of Transparent and Upconversion Photoluminescent Nanofiber Mats with Tunable Optical Properties

A facile fabrication strategy of transparent and upconversion photoluminescent nylon 6 (PA6) nanofiber mats was developed based on PA6 nanofiber mats, carboxylic acid-functionalized upconversion nanoparticles (UCNP-COOH), and poly­(methyl methacrylate) (PMMA) solution. UCNP-COOH were prepared by a solvothermal method, followed by the ligand exchange process. The electrospinning method and the spin-coating process were employed to combine PA6 nanofiber mats with UCNP-COOH and PMMA to introduce upconversion photoluminescent properties and transparency into the nanocomposite mats, respectively. The prepared UCNP-COOH/PA6/PMMA nanofiber mats are transparent and exhibit green emission, which are similar to UCNP-COOH when they were excited under 980 nm laser. The upconversion luminescent intensity of the functional nanofiber mats can be tailored by adjusting the weight fraction of UCNP-COOH as fillers. This facile strategy can be readily used to other types of intriguing nanocomposites for diverse applications

General Metal-Ion Mediated Method for Functionalization of Graphene Fiber

Graphene fibers (GFs) are attractive materials for wearable electronics because of their lightness, superior flexibility, and electrical conductivity. However, the hydrophobic nature and highly stacked structure endow GFs similar characteristics in nature to solid carbon fibers. Therefore, the interior functionalization of GFs so as to achieve synergistic interaction between graphene nanosheets and active materials thus enhance the performance of hybrid fibers remains a challenge. Herein, a general metal-ion mediated strategy is developed to functionalize GFs and nanoparticles of Cu, Fe₂O₃, NiO, and CoO are successfully incorporated into GFs, respectively. As proof-of-concept applications, the obtained functionalized GFs are used as electrodes for electrochemical sensors and supercapacitors. The performances of thus-devised fiber sensor and supercapacitor are greatly improved