Nanomechanics of few-layer materials: do individual layers slide upon folding?

Pulsed Electrochemical Exfoliation for an HF-Free Sustainable MXene Synthesis

MXenes are a 2D materials (2DM) class with high industrialization potential, owing to their superb properties and compositional variety. However, ensuring high etching efficiency in the synthesis process without involving toxic, hazardous or non-sustainable chemicals are challenging. In this work, an upscalable electrochemical MXene synthesis is presented. This novel protocol uses a non-toxic and sustainable sodium tetrafluoroborate/hydrochloric acid (NaBF4/HCl) electrolyte and increases etching efficiency by applying cathodic pulsing via pulse voltammetry. Hydrogen bubble formation restores electrochemical activity, and effectively supports 2D-sheet removal, allowing continuous etching at higher yields in situ. In detail, yields of up to 60% electrochemical MXene (EC-MXene) with no byproducts from a single exfoliation cycle are achieved. EC-MXene had an excellent quality with high purity as assessed using chemical mapping by scanning electron microscopy with energy dispersive electron spectroscopy (SEM/EDX) and surface termination analysis performed with X-ray photoelectron spectroscopy (XPS) and, for the first time, with low energy ion scattering (LEIS). Further properties of EC-MXenes such as dimensions and adhesion energy of single flakes, vibrational peaks, and interlayer spacing are provided by atomic force microscopy (AFM), X-ray diffraction (XRD), Raman spectroscopy (Raman), and transmission electron microscopy (TEM) respectively. Pulsed electrochemical synthesis is key to surface reactivation at the electrodes' interface, which results in improved exfoliation and quality of EC-MXenes. This paves the way for scaling up and green industrialization of MXenes.

Cutting-edge collagen biocomposite reinforced with 2D nano-talc for bone tissue engineering

The advancement of nanobiocomposites reinforced with 2D nano-materials plays a pivotal role in enhancing bone tissue engineering. In this study, we introduce a nanobiocomposite that reinforces bovine collagen with 2D nano-talc, a recently exfoliated nano-mineral. These nanobiocomposites were prepared by blending collagen with varying concentrations of 2D nano-talc, encompassing mono- and few-layers talc from soapstone nanomaterial. Extensive characterization techniques including AFM, XPS, nano-FTIR, s-SNOM nanoimaging, Force Spectroscopy, and PeakForce QNM® were employed. The incorporation of 2D nano-talc significantly enhanced the mechanical properties of the nanobiocomposites, resulting in increased stiffness compared to pristine collagen. In vitro studies supported the growth and proliferation of osteoblasts onto 2D nano-talc-reinforced nanobiocomposites, as well as showed the highest mineralization potential. These findings highlight the substantial potential of the developed nanobiocomposite as a scaffold material for bone tissue engineering applications.

Review on infrared nanospectroscopy of natural 2D phyllosilicates

Phyllosilicates have emerged as a promising class of large bandgap lamellar insulators. Their applications have been explored from the fabrication of graphene-based devices to 2D heterostructures based on transition metal dichalcogenides with enhanced optical and polaritonics properties. In this review, we provide an overview of the use of infrared (IR) scattering-type scanning near-field optical microscopy (s-SNOM) for studying nano-optics and local chemistry of a variety of 2D natural phyllosilicates. Finally, we bring a brief update on applications that combine natural lamellar minerals into multifunctional nanophotonic devices driven by electrical control.