Search Results (106)

This in vitro study evaluated the shear bond strength (SBS) of resin cement to diabetic and non-diabetic dentin following immediate dentin sealing (IDS) or conventional bonding without IDS, under two cementation protocols: immediate cementation (IC) and one-week delayed cementation (DC) after provisionalization. From a biomimetic perspective, IDS represents a tissue-preserving adhesive approach aimed at maintaining a stable resin–dentin interface; however, systemic conditions such as diabetes mellitus may alter the dentin substrate and affect adhesive performance. A total of 120 extracted human molars were divided into diabetic (n = 60) and non-diabetic (n = 60) groups, each further categorized by adhesive strategy (IDS or without IDS) and cementation protocol (IC or DC). IDS was performed using a three-step etch-and-rinse adhesive system, and cementation was completed with a dual-cure resin cement. Differences in SBS were observed between diabetic and non-diabetic dentin, adhesive strategies, and cementation protocols. Across all conditions, IDS-treated specimens exhibited higher bond strength than those without IDS, and DC resulted in lower SBS than IC in both adhesive strategies. In all subgroups, non-diabetic dentin showed greater SBS than diabetic dentin. The highest SBS was recorded in the non-diabetic IDS-IC group, whereas the lowest was observed in the diabetic without IDS–DC group. Under the tested laboratory conditions, IDS-treated groups showed higher SBS than the corresponding groups without IDS, while the immediate cementation protocol resulted in higher SBS than the delayed cementation protocol. Full article

Background/Objectives: Direct bonding of orthodontic brackets is standard in fixed-appliance therapy, but clinical success depends on achieving reliable bond strength without compromising enamel integrity during debonding. This in vitro study evaluated whether applying a metal primer to stainless-steel bracket bases affects shear bond strength (SBS) to enamel, and whether primer coverage and bracket-base design influence adhesive-remnant distribution and enamel integrity. Methods: A total of 132 extracted human maxillary premolars were randomly allocated to six groups (n = 22 each) defined by bracket base design (mesh or integral) and primer coverage (none, full, or partial central coverage). Brackets were bonded with Transbond XT, and Reliance Metal Primer was applied according to group allocation. After 2000 thermal cycles (5–55 °C), specimens were debonded in shear at 1 mm/min. SBS was calculated, adhesive remnants were quantified with ImageJ and scored using the adhesive remnant index (ARI), and enamel damage was assessed using an enamel damage index (EDI). Results: Mean SBS values were 15.68 MPa (MC), 18.38 MPa (MF), 20.89 MPa (MP), 13.04 MPa (IC), 17.11 MPa (IF), and 12.66 MPa (IP). Two-way ANOVA showed significant main effects of bracket base design (F(1, 126) = 16.06, p < 0.001, partial η² = 0.113) and primer coverage (F(2, 126) = 3.98, p = 0.021, partial η² = 0.059), together with a significant bracket-base-design × primer-coverage interaction (F(2, 126) = 4.46, p = 0.014, partial η² = 0.066). ARI distributions differed significantly across the six experimental groups (χ²(15) = 75.24, p < 0.001, Cramér’s V = 0.436), whereas EDI scores did not differ significantly among groups (p = 0.756). Conclusions: The effect of the metal primer on SBS depended on bracket base design and primer coverage. Partial coverage produced the highest SBS among mesh-base brackets and was significantly higher than the mesh control. Among integral-base brackets, full coverage yielded the highest numerical SBS, but within-design pairwise differences were not significant. ARI failure patterns also varied significantly across the six experimental groups, whereas no significant difference in stereomicroscopically detectable enamel damage was observed. Full article

In cold and humid regions, icing events often occur on wind turbines. The phenomenon changes the profile of the aerodynamic airfoil and reduces the power generation efficiency of wind turbines. In the present study, icing tests were conducted in an icing wind tunnel based on NACA0018 airfoils made of fiber reinforced plastics (FRP) and aluminum alloy to investigate the effects of material type and wind speed on the characteristics of icing, including the icing area, the thickness of ice and the adhesive strength of ice. The experimental results indicated that the types of ice on the FRP airfoil and aluminum alloy airfoil were mixed ice and rime ice, respectively. The icing area increased linearly with icing time. The aluminum-alloy airfoil exhibited greater ice accretion at 6 and 10 m/s, whereas the FRP airfoil showed greater ice accretion and a broader ice-covered region at 14 m/s. The FRP airfoil also had a higher adhesive strength. The research in the present study provided an experimental foundation for anti- and de-icing technology development of wind turbine blades. Full article

Natural water-repellent surfaces use hierarchical texture and low surface energy to minimize liquid adhesion, and this principle has inspired engineered superhydrophobic surfaces for passive anti-icing. However, whether such bioinspired water-repellent architectures remain beneficial during freezing and ice detachment depends on the stability of the wetting state and on the interaction between surface texture and coating chemistry. This study evaluates the anti-icing performance of smooth and laser-textured 1050A aluminum surfaces functionalized with different hydrophobic agents. Freezing delay measurements at −18 °C and ice adhesion strength measurements at −20 °C were conducted, together with wettability, surface free energy, roughness, and morphology analyses, to compare different coatings on identical morphologies and to isolate the effect of laser-generated texture for the same coating chemistry. On smooth surfaces, fluorinated alkyl phosphonic acid coating provided the largest reduction in ice adhesion strength, decreasing it by approximately 72% relative to the non-functionalized reference, while alkyl phosphonic acid coating reduced it by approximately 50%. In contrast, polydimethylsiloxane showed the longest freezing delay, with a mean value of 907 s, whereas the fatty acid-based coatings exhibited shorter freezing delays than the bare reference surface. On laser-textured surfaces, all coatings initially produced highly water-repellent wetting states. However, the differences in ice adhesion strength were markedly reduced and no longer followed the same ranking as on smooth surfaces. Polydimethylsiloxane again exhibited the most favorable freezing delay, while fluorinated alkyl phosphonic acid showed the poorest performance on the textured substrate. These results show that the bioinspired superhydrophobic state created by laser texturing does not by itself guarantee improved anti-icing performance, as under icing conditions, texture-mediated wetting, local liquid penetration, condensation or frost formation inside the texture, and mechanical interlocking can dominate over the nominal low-surface-energy chemistry. Full article

Thermally sprayed metallic coatings on carbon fiber-reinforced polymer (CFRP) substrates often contain pores and microstructural defects that can reduce adhesion, durability, and protective performance. In this study, a hybrid graphene nanoplatelet (GNP)-fullerene C60 reinforced epoxy coating was applied to HVOF-metallized CFRP, while a carbon nanotube (CNT)-based surface treatment was used to modify surface wettability. Micro-CT and SEM analyses indicated morphological changes consistent with partial coverage of accessible surface-connected defects and modification of the metallized layer surface. Pull-off adhesion strength increased from 320 psi to 650 psi, accompanied by a shift from adhesive to cohesive failure. The optimal nanofiller formulation improved tensile strength from approximately 25 MPa to 56 MPa (124%) and Young’s modulus by approximately 47% compared with neat epoxy. Abrasion testing showed more than 50% reduction in mass loss, and electrochemical impedance spectroscopy indicated improved barrier performance after 200 h of salt spray exposure. CNT surface modification transformed the coating from hydrophilic to superhydrophobic behavior, achieving water contact angles above 155°, delaying ice formation, and reducing ice accumulation. These results indicate that combining hybrid nanocomposite coatings with CNT functionalization can improve mechanical, protective, and surface-functional performance of HVOF-metallized CFRP systems under the laboratory conditions investigated. Full article

Slippery, lubricant-infused porous surfaces demonstrate excellent anti-icing performance in the laboratory. However, natural icing is a vital challenge for the slippery surface in the application of transmission conductors, and related field studies are limited. Herein, the anti-icing behavior of a 77 nm pore-sized slippery conductor was systematically investigated under natural icing environments, and a comprehensive comparison with laboratory-simulated icing conditions was further conducted. The prepared slippery conductor exhibits excellent anti-icing performance under natural conditions (contact angle 103°, ice adhesion strength 6.8 kPa). Compared to the original conductor, it reduces ice accretion by 75% in simulated laboratory tests and 56% under natural icing. It also effectively delays the freezing of condensed droplets in low-temperature and high-humidity natural atmospheres. Surprisingly, the anti-icing mechanism of the slippery conductor in the natural environment was found to differ substantially from that in laboratory tests. Under simulated conditions, transparent ice forms directly from freezing liquid water and continuously thickens. In contrast, during natural icing, slow condensate sliding and water vapor sublimation cause the surface to be initially covered by ice particles. These particles develop into a loose ice layer with weak adhesion to the substrate, which can readily shed under environmental factors. Full article

Artificial ice specimens with controllable particle characteristics and reliable mechanical properties are essential for ice mechanics research, polar engineering, and low-temperature technologies such as ice particle jet applications. Conventional crushed-ice and sieving methods are generally time-consuming and may cause particle melting, adhesion, and poor size uniformity. In this study, an efficient ice particle preparation process based on droplet atomization and rapid phase transition was proposed and validated. Nearly spherical ice particles with a size range of 100–300 μm and an average diameter of 166 μm were produced, and artificial ice specimens with densities of 903–912 kg·m⁻³ were fabricated. The preparation efficiency reached 2.16 kg·min⁻¹. Mechanical tests showed that, as temperature decreased from −5 °C to −45 °C, the uniaxial compressive strength increased from 2.18 MPa to 6.49 MPa, while the flexural strength increased from 0.955 MPa to 3.925 MPa. Within the investigated low-loading-rate range, no clear monotonic relationship was observed between loading rate and strength. Creep tests indicated that lower temperatures inhibited time-dependent deformation, whereas higher stresses accelerated creep development. Overall, the proposed process provides an efficient and reproducible method for preparing artificial ice specimens for ice mechanics and cryogenic engineering studies. Full article

Under low-temperature and high-humidity conditions, stable ice layers readily form on asphalt pavements in cold regions, and the enhanced ice–asphalt interfacial adhesion significantly increases deicing difficulty and traffic safety risks. To clarify the factors governing ice–asphalt interfacial adhesion strength, this study combines macroscopic pull-off tests and molecular dynamics simulations to systematically investigate the effects of interfacial contact area, temperature, pull-off rate, and molecular characteristics of representative asphalt components. The pull-off results show that adhesion strength increases markedly with decreasing temperature, rising from approximately 163 kPa at −2 °C to 242 kPa at −10 °C. In contrast, the nominal adhesion strength decreases with increasing ice specimen size, suggesting that size-related interfacial heterogeneity and nonuniform stress transfer may contribute to the pull-off response. The adhesion strength also generally decreases as the pull-off rate increases. Molecular dynamics simulations show that smaller asphalt–ice interfacial models exhibit higher molecular-scale nominal adhesion responses, while temperature-dependent simulations provide short-range asphalt–ice interaction descriptors for interpreting the experimental temperature trend. The calculated short-range asphalt–ice interaction energy becomes less negative from −531.4 to −352.5 kJ mol⁻¹ with increasing temperature, supporting the experimentally observed strengthening of adhesion at lower temperatures. Single-molecule pull-off simulations of 12 representative asphalt molecules reveal pronounced molecular differences, with molecular-scale nominal adhesion strengths ranging from 303.7 to 734.6 MPa. Asphaltene and polar aromatic molecules generally show stronger adhesion, which is associated with larger projected contact area, flatter molecular configurations, and heteroatom-induced polar sites. The molecular polarity index shows a moderate positive association with molecular-scale nominal adhesion strength. These results establish a scale-aware mechanistic correspondence between macroscopic pull-off behavior and molecular interaction descriptors at the ice–asphalt interface, providing insights for interfacial adhesion regulation and anti-icing design of asphalt pavement materials in cold regions. Full article

Hydrophobic and superhydrophobic surfaces have emerged as key solutions for fluid transport, biofouling prevention, and energy efficiency, with market forecasts projecting a compound annual growth rate (CAGR) of over 15% through 2030 due to their broad range of applications. This review critically examines the principles of natural hydrophobicity, as exemplified by lotus leaves and shark skin, and their translation into engineered surfaces via micro/nanofabrication techniques, such as laser patterning, etching, and self-assembly. Recent advances in hybrid nanomaterials have demonstrated WCAs in the range of 140–160°, along with enhanced mechanical strength and chemical stability, enabling applications in self-cleaning, anti-corrosion, and oil–water separation technologies. Superhydrophobic coatings are particularly important for reducing ice adhesion by more than 80%, while drag reduction in pipelines can reach up to 30%, contributing to energy savings. Despite these advances, challenges remain in achieving long-term stability under harsh environmental conditions, minimizing environmental impact, and developing cost-effective, scalable fabrication techniques. Future directions focus on environmentally friendly, multifunctional nanocomposites with switchable wettability, including pH- and light-responsive coatings capable of reversibly transitioning between superhydrophilic (<5°) and superhydrophobic (>150°) states, paving the way for sustainable and adaptable surface technologies. Full article

Icing phenomena on wind turbine blades and components are a major problem, causing downtimes that increase maintenance costs, reducing the blade’s lifespan, or in severe cases, even leading to component damage. A nanofiber-based bi-layer liquid-infused surface (BLIS) coating was prepared and characterized, combining good adhesion to wind turbine blades with low ice adhesion. The BLIS coating was produced by a new method combining electrospinning and a heat treatment step, containing a poly ethyl-2-cyanoacrylate (PECA)-based adhesive layer, a slippery layer of poly vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) copolymer, and an infiltrated perfluoropolyether lubricant. Thermogravimetric analysis (TGA) was used to ensure the thermal stability of the polymers in the nanofiber coating layers and to optimize the heat treatment process of the layers. Microstructural changes were studied by scanning electron microscopy (SEM) and surface roughness measurements. Contact angle measurements and sliding velocity tests on wind turbine blade segments at icing conditions of 0 °C and +5 °C indicate that the water sliding properties of the BLIS coating were improved compared to uncoated blades. In addition, coated blade segments showed a 50% lower ice adhesion strength than uncoated blades. Full article

This work describes the preparation of PTFE (polytetrafluoroethylene)/SiO₂ (silicon dioxide)–ER (epoxy resin)/FR (fluorosilicone resin) superhydrophobic coatings using the spray method to improve the anti-icing and de-icing performance of transmission line insulators. The coatings exhibit a consistent fluorine distribution (32.86 wt%), which enhances their low surface energy, alongside SiO₂ nanoparticles that occupy the interstices between PTFE particles, resulting in a dense micro- and nanoscale hierarchical structure. Consequently, the coatings have good superhydrophobicity, featuring a contact angle of 173.9° and roll angle of 1.2°. Following 66 days of UV irradiation, the contact angle remains above 150°, and the roll angle is approximately 15°, accompanied by a slight increase in ice adhesion strength. Following 26 freeze–thaw cycles, the contact angle stabilizes at around 157°, showing good environmental durability. Natural icing studies validate the coatings’ good anti-icing and de-icing efficacy: in comparison to common insulators, the coated insulators demonstrate a 14.2% reduction in ice accretion weight and a 67.7% reduction in maximum ice ridge length. Full article

Permeable pavements are increasingly adopted to reduce urban runoff and support sustainable stormwater management; however, their long-term performance in cold regions is often limited by the need to maintain both hydraulic conductivity and durability under freeze–thaw cycles and de-icing salt exposure. This study investigates polyurethane (PU)-bound permeable composites based on granite aggregates for paver joint filling, permeable paver production, and monolithic permeable paving. This study provides a combined evaluation of aggregate gradation and PU binder content in relation to hydraulic performance, mechanical resistance, adhesion/cohesion, water absorption, and salt-freeze scaling resistance. Four mixtures were prepared using different combinations of 0/1 and 2/5 mm granite fractions and PU binder contents. The results showed that all mixtures exceeded the target permeability requirement of 2 × 10⁻⁵ m/s, while the coarse-only mixture with 3.0% PU binder provided the most balanced performance. This mixture achieved the highest permeability, the highest compressive and splitting tensile strength among the tested mixtures, the lowest water absorption, and the lowest surface scaling after 28 freeze–thaw cycles in 3% NaCl solution. The findings indicate that a coarse aggregate skeleton effectively bonded by the PU can support both rapid drainage and improved resistance to salt-freeze deterioration. However, further field validation under traffic loading, clogging, and long-term environmental exposure would be needed before full-scale application. Full article

Ice accumulation on critical infrastructure surfaces threatens operational safety in aviation, power transmission, and transportation systems. Conventional anti-icing and deicing strategies, such as chemical deicers and energy-intensive active heating, have inherent drawbacks. These include environmental pollution, high energy consumption, and low efficiency. In recent years, photothermal-responsive extremely water-repellent surfaces have attracted widespread attention. They can harvest renewable solar energy and achieve efficient anti-icing and deicing through tailored interfacial wetting properties. This review summarizes photothermal extremely water-repellent surfaces based on the “water as a lubricating layer” strategy. This strategy reduces ice adhesion strength and enables low-energy deicing. It works by forming a continuous lubricating film via photothermally induced interfacial meltwater. We discuss photothermal conversion mechanisms and strategies to enhance performance for stable lubricating film formation. We also analyze the stagewise physics of anti-icing and deicing, focusing on the interfacial tribological behavior of the water film. Key engineering challenges are addressed, including mechanical durability and all-weather applicability. Finally, we clarify future research directions for industrial translation. This review aims to provide theoretical insights and technical pathways for developing next-generation anti-icing and deicing surfaces that are efficient, eco-friendly, and sustainable. Full article

Superhydrophobic coatings are regarded as a promising passive anti-icing strategy; however, their practical engineering application, particularly in electrical insulation, is severely hindered by the performance deterioration caused by mechanical damage and a lack of theoretical understanding of microscopic ice adhesion mechanisms. In this study, a layered polymer composite coating was designed to resolve the trade-off between abrasion resistance and low ice adhesion. The chemistry of the coating relies on a synergistic “primer–topcoat” design: the primer consists of an epoxy resin matrix chemically modified by amino silicone oil to lower its surface energy and improve toughness, while the topcoat features hierarchical SiO₂ clusters functionalized with hexamethyldisilazane (HMDS) and silane coupling agents. This architecture was fabricated via a controllable layer-by-layer spraying method. Systematic investigations revealed that the hierarchical micro/nanostructure, composed of microscale protrusions and nanoscale SiO₂ clusters, provides excellent superhydrophobicity (contact angle of 155.2°, sliding angle of 2°). Crucially, the crosslinked polymer network and stable siloxane (Si-O-Si) covalent bonding ensure that the coating maintains its functionality after a cumulative sand impact of 3 kg, demonstrating superior mechanical durability. Furthermore, differentiated theoretical models for ice adhesion in Cassie–Baxter and Wenzel states were established based on intermolecular interactions, identifying that maintaining a stable Cassie–Baxter state is key to reducing adhesion. This study offers a robust approach to balancing functionality and durability in polymer composites through synergistic structural design, providing both a scalable fabrication strategy and a quantitative theoretical framework for understanding interfacial ice adhesion. Full article

In response to the significant challenges posed by ice accumulation and contamination from various fluids in complex operating conditions for metallic materials, this study utilises picosecond laser precision machining to develop a ‘slippery surface’ featuring a micro-channel network structure. The core innovation of this study lies in the use of laser-machined micrometre-scale array textures to overcome the limitations of traditional isolated pores. These globally interconnected micro-channels serve as highly efficient reservoirs and dynamic transport channels for lubricants, significantly enhancing the interfacial capillary locking force of the lubricant. Experimental results demonstrate that this unique network geometry endows the surface with exceptional fluid replenishment and self-healing properties, enabling it to exhibit outstanding broad-spectrum hydrophobicity towards various fluids—including water, crude oil and ethanol (surface tension range: 17.9–72.0 mN m⁻¹)—with sliding angles consistently below 12°, whilst effectively slowing the dehydration and solidification processes of biological fluids. At a low temperature of −15 °C, the surface achieved an ice formation delay of up to 286 s, with an ice adhesion strength of only 33.9 kPa, ensuring that accumulated ice could be spontaneously detached under minimal external force. Furthermore, the micro-channel network structure serves as a key protective mechanism against mechanical wear, maintaining robust slippery properties even after three hours of high-pressure water jet scouring (Weber number of 300). This reliable interface, achieved through structural management, provides an efficient and scalable platform for addressing the all-weather anti-icing and antifouling requirements of outdoor infrastructure. Full article