Controllable Surface-Grafted MXene Inks for Electromagnetic Wave Modulation and Infrared Anti-Counterfeiting Applications

Abstract

Two-dimensional transition metal carbide/nitride (MXene) conductive inks are promising for scalable production of printable electronics, electromagnetic devices, and multifunctional coatings. However, the susceptible oxidation and poor rheological property seriously impede the printability of MXene inks and the exploration of functional devices. Here, we proposed a controllable surface grafting strategy for MXene flakes (p-MXene) with prepolymerized polydopamine macromolecules to protect against water and oxygen, enrich surface chemistry, and significantly optimize the rheological properties of the inks. The obtained p-MXene inks can adapt to screen-printing and other high-viscosity processing techniques, facilitating the development of patterned electromagnetic films and coatings. Interestingly, the printed MXene polarizer can freely switch and quantitatively control microwave transmission, giving an inspiring means for smart microwave modulation beyond the commonly reported shielding function. Moreover, the introduction of polydopamine nanoshell enables the infrared emissivity of MXene coating to be adjusted to a large extent, which can produce infrared anti-counterfeiting patterns in a thermal imager. Therefore, multifunctional antioxidant p-MXene inks will greatly extend the potential applications for the next-generation printable electronics and devices.

Flexible, Stretchable, and Lightweight Hierarchical Carbon-Nanotube-Decorated Carbon Fiber Structures for Microwave Absorption

“…The impedance matching condition allows the maximum EM wave to penetrate inside the absorber. EM waves get attenuated and may be converted into heat or some other form of energy due to polarization (interfacial and dipole) and conduction loss. , The multiple internal reflections (or scattering) between the two fillers inside the nanocomposite enhance the attenuation of the EM wave . Hence, these multiple mechanisms of EM wave inside the nanocomposite greatly enhance the absorption capability .…”

Two-Dimensional Janus MXene Inks for Versatile Functional Coatings on Arbitrary Substrates

“…16,25 In other words, exploring effective strategies to broaden the dispersion duration at a high concentration of MXene to achieve large-scale manufacturing of flexible electronic devices is highly in need. 26 The formation of the Janus structure allows for the combination of materials with different properties, facilitating the realization of versatile functions and the expansion of multiple applications. However, due to the random distribution of MXene surface groups, it is difficult to achieve the modification on a single side and form an asymmetric structure.…”

“…Through such approaches, it is possible to transform the hydrophilic MXene to hydrophobic and disperse it in specific organic solvents. However, highly concentrated MXene nonpolar dispersions have not been achieved and each surface modification can only provide a narrow stable dispersibility duration because the kinetics of the dispersion process relies on the balance of thermodynamic interactions. , In other words, exploring effective strategies to broaden the dispersion duration at a high concentration of MXene to achieve large-scale manufacturing of flexible electronic devices is highly in need . The formation of the Janus structure allows for the combination of materials with different properties, facilitating the realization of versatile functions and the expansion of multiple applications.…”

3D Printing of Ultralow-Concentration 2D Nanomaterial Inks for Multifunctional Architectures

“…Even at the same constituent concentrations, the cell diameter of MXene foams can be tuned from 100 ± 27 to 51 ± 14 μm by increasing the emulsification speed from 1500 to 3000 rpm (Figures 3c−e, S9e, f, and S10), a clear manifestation of the kinetically trapped nature of the structures formed. In addition, other architectures with densities of as low as 2.8 g/cm 3 were printed using GO emulsion-based inks after annealing (Figure S11). Consequently, the characteristics of the foams produced in terms of cell size, the connectivity between the cells, cell wall functionality, and the resultant density can be tuned over a large range, underscoring the great flexibility in generating porous materials with the desired performance (e.g., mechanical property) using the emulsion-based ink process decried here.…”

“…Macroscopic porous structures assembled from 2D nanomaterials have witnessed significant progress in a wide range of applications, including energy storage, thermal management, electromagnetic interference (EMI) shielding, , catalyst supports, and sensors . Various processing strategies, including self-assembly, templating, coating, and printing, have been used to produce macroscopic monoliths from 2D nanomaterials, however, the precise control over the structures and properties of the monoliths remains a challenge, especially at ultralow bulk densities.…”