Integrating environmental robustness, energy-efficient recoatability and multi-scenario applicability into a single durable coating that can resist the accumulation of liquid, solid, and mold contaminants is critical for the sustainable development of the coatings industry, yet remains a significant challenge. Here, this issue is addressed by developing a novel hydrophilic-hydrophobic conversion strategy to engineer an environmentally robust organic/inorganic hybrid superhydrophobic coating with remarkable anti-soiling properties and pH-induced recoatability. This conversion, achieved through surface chemistry regulation incorporating hydrophobic hydrocarbon chains and aminopropyl functional groups, yields a coating with a high water contact angle (WCA) of 155.4 degrees and a low sliding angle (SA) of 1.3 degrees. Notably, the WCA can reversibly transition to 0 degrees within 15 s under pH adjustment. The wide range of the surface energy variations enables effective recoatability and restores surface wettability in damaged coatings, with an adhesion strength up to 5.34 MPa, allowing for the in-situ reuse of old coatings. The uniform distribution of modified silica nanoparticles within semi-cured epoxy matrix imparts satisfactory environmental durability, allowing the composite coating to retain its superhydrophobicity after enduring various harsh conditions, including 100 cycles of sandpaper abrasion, 70 cycles of tape-peeling, 120 h of water immersion, and 168 h of heat and humidity exposure. Additionally, the coating demonstrates enhanced anti-mold performance, achieving a grade 1 rating. This work introduces a novel design and fabrication method for multifunctional pH-triggered recoatable superhydrophobic coatings with enhanced environmental robustness that significantly extends their lifespan and adaptability.

Plastic-coated paper straws are insufficient to solve the plastic pollution problem because microplastics are formed during their degradation. In this study, upgraded paper straws were prepared by coating with biodegradable sodium alginate/cellulose nanofiber/stearic acid (SA/CNF/STA) on the surface of paper without additional adhesives. The tensile strength of the paper was enhanced synergistically by the coated SA and CNF after cross-linking with Ca2+ ions, reaching a maximum (26.46 MPa) when the mass ratio of SA to CNF was 4:1. The straws were prepared by spirally winding coated paper into tubes. Subsequent STA modification with different concentration (1-40%) improved the water stability of the paper straws. The paper straws exhibited excellent mechanical properties (including 13.45 MPa of flexural strength, 13.30 MPa of compressive strength) and hydrophobicity (103.67 degrees of maximum water contact angle). After 130 days of soil burial, the paper straws were completely degraded. The comprehensive performance of prepared straws exceeds that of commercially available products in the same category, and they are safe and biodegradable. Paper straw in the work is in line with the concept of green and low-carbon development.

The 2021 Navalacruz wildfire occurred in a mountainous area in the Sistema Central (Spain). Despite having an average low severity index (dNBR), the loss of vegetation cover associated with the fire was responsible for a high rate of sedimentation in the rivers and streams. Additionally, the burned area affected up to 60 cultural heritage sites, including archaeological and ethnological sites, and damage ranged from burnt pieces of wood to the burial of archaeological sites. In the present work, we document and analyze the post-fire evolution in several rivers and streams. This is based on a field survey of infiltration rates, hydrodynamic modeling, and the study of channel morphological changes. Our analysis revealed how the first post-fire rains caused the mobilization and transport of ashes. This created hydrophobicity in the soils, resulting in large amounts of materials being transported to rivers and streams by subsequent medium- and low-magnitude storms. A hydrological and hydraulic model of the study catchments under pre- and post-fire conditions suggests that these trends are a consequence of a post-fire increase in flow rates for similar rainfall scenarios. In this respect, our estimates point at a significant increase in sediment transport capacities associated with this post-fire increase in flow rates. The combination of locally steep slopes with high-severity fire patches, and a considerable regolith (derived from pre-fire weathering), resulted in a series of cascading responses, such as an exacerbated supply of sand to the drainage network and the triggering of debris flows, followed by erosion and entrenchment.