The application of superhydrophobic (SH) coatings in road construction has attracted growing attention due to their potential to improve surface durability, reduce cracking, and enhance skid resistance. Among various materials, SiO₂ nanoparticles have emerged as key components in SH coatings by contributing essential surface roughness and hydrophobicity. This review paper analyzes the role of SiO₂ nanoparticles in enhancing the water-repellent properties of coatings applied to road surfaces, particularly concrete and asphalt. Emphasis is placed on their influence on road longevity, reduced maintenance, and overall performance under adverse weather conditions. Furthermore, this review compares functionalization techniques for SiO₂ using different hydrophobic modifiers, evaluating their efficiency, cost effectiveness, and scalability for large-scale infrastructure. In addition to highlighting recent advancements, this study discusses persistent challenges—including environmental compatibility, mechanical wear, and long-term durability—that must be addressed for practical implementation. By offering a critical assessment of current approaches and future prospects, this short review aims to guide the development of robust, high-performance SH coatings for sustainable road construction.

This study presents the synthesis, characterization, and evaluation of stearic-acid-coated sand (SACS) as a superhydrophobic material for agricultural water management applications. The fabrication process involves coating silica sand particles with stearic acid in an ethanol-based solution, followed by controlled drying to achieve a stable and uniform hydrophobic layer. Structural, chemical, and physical characterizations confirmed the successful functionalization of the sand surface. The coated sand exhibited a high water contact angle (WCA > 150°), indicating strong water repellency and potential for reducing water loss in soil systems. Experimental results demonstrated enhanced moisture retention in SACS-treated soil, prolonging water availability by up to four additional days compared to untreated samples. Despite its promising performance, potential degradation under acidic or organic solvent exposure remains a concern for long-term application. Overall, this work presents SACS as a low-cost, scalable solution to improve water conservation in dry agricultural areas, supporting sustainable farming practices.

Thin films of nickel oxide (NiO) were deposited on a 5° miscut magnesium oxide (MgO)(100) substrate using electron-beam evaporation to pursue morphology-directed resistive switching. The atomic force microscope (AFM) confirmed a stepped surface with a terrace width of ~85 nm and a step height of ~7 nm. After deposition, the film resistance decreased from 200 MΩ to 25 MΩ by annealing under ambient air at 400 °C, attributed to the increase in the p-type conductivity through nickel vacancy formation. Top electrodes of Ag (500 nm width, 180 nm gap) were patterned parallel or perpendicular to the substrate steps using UV and electron-beam lithography. Devices aligned parallel to the step showed reproducible unipolar switching with 100% yield between forming voltages 20–70 V and HRS/LRS~10² at ±5 V. In contrast, devices formed perpendicular to the steps (8/8) subsequently failed catastrophically during electroforming, with scanning electron microscopy (SEM) showing breakdown holes on the order of ~100 nm at the step crossings. The anisotropic electrodynamic response is due to step-guided electric field distribution and directional nickel vacancy migration, illustrating how substrate morphology can deterministically influence filament nucleation. These results highlighted stepped MgO as a template to engineer the anisotropic charge transport of NiO, exhibiting a reliable ReRAM as well as directional electrocatalysis for energy applications.

Room-temperature porous silicon ammonia sensor with 42% sensitivity, wireless IoT connectivity, and rapid 20s response for industrial safety monitoring.

This paper presents the growth and in situ optical characterization of silicon nanowires (Si NWs) on Al₂O₃(0001) substrates that are thermally faceted using the atomic low angle shadowing technique (ATLAS) method. Annealing Al₂O₃ substrates in air before surface faceting was used for the first time, as identified by atomic force microscopy (AFM). Planar Si NW arrays were subsequently deposited and characterized in real-time by reflectance anisotropy spectroscopy (RAS). RAS measurements detected irreversible spectral changes during growth, e.g., red-shift in peak energy for marking amorphous Si NW formation. Blue-shifts in RAS spectra following annealing post-growth at varied temperatures were found to be associated with structural nanowire development. AFM analysis following annealing detected dramatic changes in morphology, e.g., quantifiable differences in NW height and thickness and complete disappearance of nanowire structures at high temperatures. These results confirm the validity of in situ RAS as a monitoring tool for nanowire growth and illustrate Si NW morphology’s sensitivity to thermal processing.

Magnetite (Fe3O4) thin films were epitaxially grown on stepped MgO(100) substrates to investigate resistive switching (RS) behavior in the presence of surface steps. The films exhibited hysteresis in current–voltage (I–V) measurements below the Verwey transition temperature (TV ≈ 120 K), revealing anisotropic RS behavior depending on the direction of the applied electric field. When the electric field was applied parallel to the surface steps, stable switching was observed with over 16 000 cycles at 95 K, without degradation. In contrast, when the field was applied perpendicular to the steps, switching was observed down to 85 K. However, at 80 K, the device showed complete failure due to the interaction of the electric field with antiphase boundary defects along the steps. These findings highlight the role of surface morphology in modulating RS behavior and provide insights into the mechanisms governing RS in Fe3O4, consistent with theoretical predictions of charge gap closure under an applied electric field. The results emphasize the significance of substrate steps in controlling the RS characteristics of magnetite thin films.