Nanomaterials

High-flexibility copper foils are critical for reliable flexible interconnects and displays. In this work, commercial-purity copper belts were processed by triple-layer stacked cold rolling to ultrathin foils, producing distinct surface- and layer-dependent deformation structures in the bright, matte, and central-interface layers; subsequent annealing at 600 °C then promoted orientation-selective recrystallization. Under the present conditions, the center-interface layer of the triple-rolled foil achieved the highest flexural-fatigue life (≈8.0 × 10⁴ cycles) within a window of cube ≈ 30–45% and grain size ≈ 40–60 μm. In this regime, grain-size control stabilizes intergranular slip compatibility, reduces elastic–plastic mismatch, and mitigates strain localization during cyclic bending. Even without aggressive cube enrichment, high flexural fatigue resistance can likewise be achieved through deliberate control of grain size. These findings establish a clear processing–microstructure–property linkage and indicate that layer-dependent control of texture and grain size can enhance flexural-fatigue performance in triple-layer stacked-rolled copper foils for flexible electronics.

In this study, nanocrystalline dysprosium oxide (Dy₂O₃) thin films were deposited on sapphire and quartz glass substrates by an electron beam evaporation technique to comparatively evaluate the influence of substrate type on their structural and optical properties. X-ray diffraction (XRD) confirms that all films exhibit a polycrystalline nature and possess a cubic-type structure. The Debye–Scherrer equation was used to determine the average crystallite size and it was found that the film deposited on quartz glass substrate is slightly larger than the film deposited on the sapphire substrate. Scanning electron microscopy (SEM) revealed a granular morphology for the sapphire film and a more compact, pore-free surface for the quartz film. Spectroscopic ellipsometry (SE) and UV-Vis spectrophotometry were employed to extract the optical constants and reflectance behavior, respectively. The film on sapphire exhibited a lower refractive index, higher extinction coefficient, and reduced reflectance, confirming its enhanced anti-reflective performance. The study provides new insights into how the substrate affects the optical properties of Dy₂O₃ thin films. This study demonstrates that sapphire is a more suitable substrate for enhanced anti-reflective and optoelectronic applications.

Developing sustainable, high-performance biomass composites is crucial for replacing non-renewable structural materials. In this study, a “bamboo steel” composite was fabricated using a multilevel modification strategy involving alkali pretreatment, toughened resin impregnation, and surface functionalization. Bamboo fibers were treated to remove hemicellulose and lignin, enhancing porosity and interfacial bonding. The bamboo scaffold was subsequently impregnated with a thermo-plastic polyurethane-modified epoxy resin to create a robust, interpenetrating network. The optimized composite (treated at 80 °C) exhibited a flexural strength of 443.97 MPa and a tensile strength of 324.14 MPa, demonstrating exceptional stiffness and toughness. Furthermore, a superhydrophobic coating incorporating silica nanoparticles was applied, achieving a water contact angle exceeding 150° and excellent self-cleaning properties. This work presents a scalable strategy for producing bio-based structural materials that balance mechanical strength with environmental durability.