Atomic-scale defects are ubiquitous in nanomaterials, yet their role in modulating fluid flow is inadequately understood. Hexagonal boron nitride (hBN) is an important two-dimensional material with applications in desalination and osmotic power. Although pristine hBN offers higher friction to the flow of water than graphene, we show here that certain defects can enhance water slippage on hBN. Using classical molecular dynamics simulations assisted by quantum-mechanical density functional theory, we compute the friction coefficient of water on hBN containing various vacancies (B, N, BN, BN, and BN) and the Stone-Wales defect. By investigating two defect concentrations, we obtain friction coefficients ranging from 0.4 to 2.6 times that of pristine hBN, leading to a maximum water slip length of 18.1 nm on hBN with a N vacancy or a Stone-Wales defect. Our work informs the use of defects to tune water flow and reveals defective hBN as an alternative high-slip surface to graphene.
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http://dx.doi.org/10.1021/acs.nanolett.1c02208 | DOI Listing |
J Anim Ecol
January 2025
Environmental Defense Fund, Seattle, Washington, USA.
For similar species to co-occur in places where resources are limited, they need to adopt strategies that partition resources to reduce competition. Our understanding of the mechanisms behind resource partitioning among sympatric marine predators is evolving, but we lack a clear understanding of how environmental change is impacting these dynamics. We investigated spatial and trophic resource partitioning among three sympatric seabirds with contrasting biological characteristics: greater crested terns Thalasseus bergii (efficient flyer, limited diver, and preference for high quality forage fish), little penguins Eudyptula minor (flightless, efficient diver, and preference for high quality forage fish) and silver gulls Chroicocephalus novaehollandiae (efficient flyer, limited diver and generalist diet).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, P.R. China.
Silicone rubber (SR) holds significant potential for everyday wearable devices due to its inherent sweat resistance and flexibility. However, its broader applicability is constrained by poor oil resistance and a suboptimal slip performance. In this study, we developed an SR with durable oil resistance and enhanced slip properties by forming a covalently bonded barrier layer on its surface through a one-step in situ fluorination reaction using F/N.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Engineering, University of Liverpool, Liverpool, L69 3GH, United Kingdom.
Hypothesis: We hypothesise that superhydrophobic surfaces can achieve effective interfacial slip and drag reduction even under non-Newtonian, shear-thinning fluid flows. Unlike Newtonian fluids, where slip is primarily influenced by viscosity and surface tension, we anticipate that the shear-thinning nature of these fluids may enhance slip length and drag reduction.
Experiments And Numerical Analysis: The superhydrophobic surfaces used in this study, featuring a dual-scale random topography, were fabricated via a spray coating process, and low-concentration xanthan gum solutions (50-250 ppm) were used as model shear-thinning fluids of low elasticity.
Langmuir
January 2025
Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112, United States.
Slip flow, a fluid flow enhanced in comparison to that calculated using continuum equations, has been reported for many nanopores, mostly those with hydrophobic surfaces. We investigated the flow of water, hexane, and methanol through hydrophilic nanopores in silica colloidal crystals. Three silica sphere sizes were used to prepare the crystals: 150 ± 30, 500 ± 40, and 1500 ± 100 nm.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Polytechnic School of Engineering, Campus de Viesques, University of Oviedo, 33203 Gijón, Spain.
In some occasions, outdoor steel structures like wind towers, bridges, winter sports facilities, and so on are subjected to extreme environmental conditions with the presence of ice and/or with below-zero temperatures. Sometimes in these situations, surface protection of the steel structure is usually designed using hot-dip galvanizing to improve its durability. In these special circumstances, the structure's connections are also exposed to adverse climatic agents.
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