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Condensation is a vital process integral to numerous industrial applications. Enhancing condensation efficiency through dropwise condensation on hydrophobic surfaces is well-documented. However, no surfaces have been able to repel liquids with extremely low surface tension, such as fluorinated solvents, during condensation, as they nucleate and completely wet even the most hydrophobic interfaces. Here, we introduce a surface functionalization methodology that enables dropwise condensation of fluorinated refrigerants. This approach, compatible with various substrates, combines low contact angle hysteresis Parylene-C with low surface energy silane (P-HFDS) using a highly scalable atmospheric vapor phase deposition technique. Our experimental results demonstrate that the omniphobic P-HFDS coating facilitates dropwise condensation of both natural refrigerants (water, ethanol, hexane, pentane) and synthetic low-global-warming-potential refrigerants (HCFO R1233zd(E) and HFO R1336mzz(Z)) with surface tension as low as 14.6 mN m−1 at 25°C. The P-HFDS coating improves condensation heat transfer coefficients by 274%, 347%, 636%, and 688% for ethanol, hexane, pentane, and R1233zd(E), respectively, compared to filmwise condensation on uncoated metal surfaces. Additionally, the coating demonstrates long-term durability, sustaining steady dropwise condensation for 170 days without apparent degradation. This work pioneers stable dropwise condensation of multiple refrigerants on a structure-less surface, offering a durable, substrate-independent, and scalable solution for low surface energy coatings. Achieving long-term sustainable dropwise condensation of low-surface-tension refrigerants has been a decades-long challenge. The authors introduce a coating that facilitates dropwise condensation of fluorinated refrigerants, significantly improving heat transfer and showcasing durability across various substrates. [ABSTRACT FROM AUTHOR]

Throughout the last centuries, European climate changed substantially, which affected the potential to plant and grow crops. These changes happened not just over time but also had a spatial dimension. Yet, despite large climatic fluctuations, quantitative historical studies typically rely on static measures for agricultural suitability due to the non-availability of time-varying indices. Relying on recent advances in paleoclimatology, we bridge this gap by constructing a spatio-temporal measure for agricultural suitability across Europe for a period of 500 years. Our gridded index has a 0.5° resolution and is available at a yearly level. It relies on a simple surface energy and water balance model, focusing only on so-called exogenous geographic and climatic features. Our index captures not just long-term trends, such as the Little Ice Age, but also short-term climatic shocks. It will empower researchers to explore the interplay between climatic fluctuations and Europe's agricultural landscape, analyze human responses at a local and regional scale, and foster a deeper understanding of the region's historical dynamics. [ABSTRACT FROM AUTHOR]

In response to the growing demands for cotton fabric across different applications, the development of multifunctional fabric has garnered significant attention. However, it is still a great challenge to simultaneously realize functions such as flame retardancy, washing durability and water repellency of fabric. In this work, an eco-friendly multifunctional cotton fabric (CF-PZF/PDMS) with durable flame retardancy and superhydrophobicity was successfully prepared through nanotechnology and surface modification methods, which included the impregnation with phytic acid (PA), in-situ growth of zeolitic imidazolate framework-8 (ZIF-8) and spraying of polydimethylsiloxane (PDMS). Due to the synergistic effect of nitrogen, phosphorus and silicon elements, as well as the catalytic charring effect of transition metal (Zn2+) in ZIF-8 nanoparticles, CF-PZF/PDMS fabric had excellent flame retardancy and washing durability, with a limiting oxygen index (LOI) of 34.5% and a char length of 38 mm. Even after 20 washing cycles, CF-PZF/PDMS fabric still maintained an LOI value of 29.6%, exhibiting great self-extinguishing. Furthermore, the rough structure with hierarchical micro/nano-scale protuberances constructed by ZIF-8 and low surface energy of PDMS endowed CF-PZF/PDMS fabric with excellent superhydrophobicity and self-cleaning properties, evidenced by a water contact angle (WCA) of 152.8°. Notably, this fabric possessed excellent selective oil absorption capacity, high efficiency (more than 97%) in separating various oil–water mixtures, as well as superior stability in repetitive use. This study presents a straightforward method for fabricating multifunctional cotton fabric, which has promising applications in the field of advanced functional textiles and oil–water separation. [ABSTRACT FROM AUTHOR]

The preparation of durable super-hydrophobic cotton fabrics (CFs) poses a significant challenge for oil–water separation, primarily due to nanoparticle loss and the utilization of toxic auxiliaries. This study proposes a sustainable method for creating superhydrophobic CFs. Initially, CFs are treated with a mixture of NaOH and urea at low temperatures to enhance surface roughness while preserving mechanical integrity. Subsequently, hexadecyl trimethoxysilane (HDTMS) and butane tetracarboxylic acid (BTCA) are applied to reduce fiber surface energy. This combined approach results in CFs with outstanding superhydrophobic properties, boasting a water contact angle of up to 155°, surpassing nanoparticle-based surfaces. Furthermore, these fabrics exhibit remarkable mechanical and chemical stability, along with enduring washing durability. Notably, they demonstrate effective self-cleaning abilities in the presence of liquid contaminants and excellent oil/water separation performance with a high separation efficiency. The developed CFs hold promise for diverse applications in both household and industrial settings. [ABSTRACT FROM AUTHOR]

Water repellency of superhydrophobic protective film is of great interest to anti-corrosion of metallic materials due to its reduced contact area with water containing aggressive ions and self-cleaning effect. In this study, a facile electrochemical method was presented for preparing superhydrophobic film with excellent anti-corrosion and self-cleaning properties on Al alloy. The superhydrophobic film comprised nickel–cobalt phosphate (NiCoPO) with a hierarchical micro-nano structure and stearic acid (STA) with low surface energy, while the NiCoPO provides an appropriate roughness and STA offers an inert chemical state. As expected, the superhydrophobic film of NiCoPO/STA on Al alloy demonstrates a champion water contact angle of 163º and corrosion protection efficiency of 97.38%. Moreover, the water flow impact-bounce and abrasion measurements on the NiCoPO/STA surface demonstrate that the superhydrophobic film possesses decent mechanical durability. This facile electrochemical deposition method paves a universal pathway to fabricate superhydrophobic protective film with remarkable anti-corrosion and self-cleaning performance on metallic substrates. [ABSTRACT FROM AUTHOR]

Ag thin films are used in a variety of electrical devices, but they easily condense owing to the low cohesive energy of Ag. In this study, Bi- and Sb-assisted growth techniques were utilized to improve the stability of Ag thin films. Thin films of Ag, Bi-doped Ag, and Sb-doped Ag were deposited on polyimide (PI) films at 160 and 320 °C by radio frequency magnetron sputtering. The thin-film orientation and strain were determined by analyzing the X-ray diffraction patterns. In addition, the adhesiveness between the thin films and PI substrates was evaluated by immersion tests. The [111] growth of the Ag thin films was assisted by Bi at 160 °C and by Sb at 320 °C, where the (111) orientation possesses the lowest surface energy for the face-centered cubic structure of the Ag thin films. The strain present in the PI film was not applied to the grown thin films. Doping with Bi or Sb decreased the thin-film strain and prevented the detachment of the Ag thin film from the PI film in pH 9 buffer, with the exception of the Sb-doped Ag thin film grown at 160 °C, which exhibited non-uniform growth. Thus, Bi or Sb doping can suppress the condensation of Ag thin films by enhancing their (111) orientation and adhesiveness to the substrate. The obtained results indicate that Bi- and Sb-assisted growth techniques can stabilize Ag thin films and improve the reliability of devices based on these films. [ABSTRACT FROM AUTHOR]

Significant restrictions have been found in the selection of piezoelectric materials and the direction of wave propagation in earlier studies on surface acoustic wave sensors. The primary goal of the current work is to investigate how wave propagation direction influences the performance of SAW macro- and nano-sensors in an effort to remove such barriers in the technological revolution of SAW sensors. A proposed model is established to study Shear Horizontal (SH) and anti-plane SH wave propagation in piezoelectric materials with surface effects. The theoretical forms are constructed and used to present the wavenumber of surface waves in any direction of the piezoelectric medium, based on the Extended Stroh formalism. In addition, we take into account surface elasticity theory in order to obtain the phase velocity equation based on the wavenumber expression. The model incorporates surface elasticity, piezoelectricity, and permittivity to account for nanoscale surface phenomena. Two configurations are examined: an orthotropic piezoelectric material layer over an elastic framework and a piezoelectric material half-space with a nano substrate. Analytical expressions for frequency equations are derived for both symmetric and anti-symmetric waves. Numerical results highlight the critical thickness of the piezoelectric layer, where surface energy significantly influences dispersion properties. The effects of surface elasticity and density on wave velocity are analyzed, revealing a spring force-like influence on boundaries. The research investigates SH wave transmission in anisotropic, transversely isotropic piezoelectric nanostructures. The findings could aid in designing SAW devices and piezoelectric sensors, as well as producing more effective surface acoustic wave sensors, based on recent theoretical work summaries. [ABSTRACT FROM AUTHOR]

Superhydrophobic cotton fabrics have received much attention in recent years. They have been constructed usually by lowering surface energy and increasing surface roughness. Because of the significant environmental harm caused by fluorine-containing reagents, difficult preparation techniques, and low wear resistance, finding a simple approach to prepare a fluorine-free, wear-resistant, strongly sticky superhydrophobic cotton fabric remains a challenge. In this study, we describe a fluorine-free superhydrophobic cotton fabric using the simple preparation approach of immersion, which creates nanoscale siloxane aggregates dispersible in organic solvents. The modified cotton fabrics are characterized by scanning electron microscopy, fourier-transform infrared, and energy dispersive spectroscopy. Excellent superhydrophobicity (ultrahigh water contact angle is 165.2° and sliding angle is 7.2° as well as excellent self-cleaning properties) has been easily applied to cotton fabrics. Superhydrophobic cotton fabrics also have good anti-fouling properties for many common types of liquids, such as milk, coffee, cola, etc. It has been established that these waterproof coatings exhibit outstanding mechanical endurance against water impact, abrasion, and laundering. Superhydrophobic fabrics have a wide range of possible uses due to their readily available coating materials, simple application technique, and strong mechanical endurance. [ABSTRACT FROM AUTHOR]

To improve the wound dressing characteristics of bacterial cellulose-based materials and address the issue of asymmetric wound dressing with one hydrophilic side and another hydrophobic side, this study developed a new concept for the fabrication of an asymmetric wettable and antibacterial wound dressing by selective drop coating of stearic acid-modified ZnO, chitosan, and AgNPs to form a dot pattern on both surfaces of a bacterial cellulose–alginate composite (BA-ZnS/Ch/Ag). The coated surface was hydrophobic, with a WCA of 150° due to the formation of a low surface energy zinc stearate (C17H35COO)2Zn) monolayer on the ZnO particles and a high degree of hierarchical roughness. The asymmetric wettable BA-ZnS/Ch/Ag wound dressing maintained good water absorptivity (swelling rate 417%) and natural breathability (water vapor transmission rate 792 g.m−2 day−1) of the superhydrophilic bacterial cellulose-alginate composite that consisted of dense outer surfaces and porous inner layers and simultaneously possessed the superhydrophobic property of the coating area that can reduce the risk of infection from external fluids and improve the blood repellency and anti-adhesion properties. The BA-ZnS/Ch/Ag wound dressing showed good antibacterial activity against S. aureus and E. coli and non-toxicity to human keratinocyte immortal cells (HaCaT), making it suitable for clinical applications. [ABSTRACT FROM AUTHOR]

We examined the structural, relaxation, and electronic properties of the bulk and (1 1 1) surfaces of cubic perovskite RbTaO3 using first-principles density functional theory (DFT). We used the DFT-VASP code for our calculations. The Rb and O atoms in the RbO3 (1 1 1) termination had a large atomic displacement (ΔZ) in the top and ninth layers, whereas the Ta atoms in the termination had a large ΔZ in the second and eighth layers. The Rb and O atoms in the Ta (1 1 1) termination had a large ΔZ in the second and eighth layers. The surface energy (Esurf) calculated for the RbO3 (1 1 1) termination was 7.96 eV, smaller than that for the Ta (1 1 1) termination, with Esurf of 7.11 eV. The cleavage energy required at the Ta or RbO3 (1 1 1) termination was 8.77 eV. The bulk system exhibited a semiconducting nature with a bandgap (Eg) of 2.25 eV. The RbO3 and Ta terminations exhibited half-metallic ferromagnetism (HMF) with a spin magnetic moment of 5.00 μβ. The Eg values of the RbO3 and Ta (1 1 1) surfaces were 2.45 eV and 2.55 eV, respectively. We also used the DFT-B3LYP CASTEP code to calculate Eg. The Eg of the RbTaO3 bulk was 2.40 eV. The Eg values of the RbTaO3 (1 1 1) surface were 2.65 and 2.50 eV for the Ta and RbO3 terminations, respectively. We also calculated the atomic populations (Q) and variations (ΔQ) of the Ta and RbO3 (1 1 1) terminations and compared them with those of the bulk system. [ABSTRACT FROM AUTHOR]

Quantum computers promise a qualitative speedup in solving a broad spectrum of practical optimization problems. The latter can be mapped onto the task of finding low-energy states of spin glasses, which is known to be exceedingly difficult. Using D-Wave's 5000-qubit quantum processor, we demonstrate that a recently proposed iterative cyclic quantum annealing algorithm can find deep low-energy states in record time. We also find intricate structures in a low-energy landscape of spin glasses, such as a power-law distribution of connected clusters with a small surface energy. These observations offer guidance for further improvement of the optimization algorithms. [ABSTRACT FROM AUTHOR]

The paper presents the results of a study on the development of polymer clay nanocomposite for flexible packaging. The studies have shown that the inclusion of nanocomposite layer in the composition of multilayer materials leads to a decrease in the rate of oxygen passage through the material. The use of nanocomposite layer in the composition of film laminates leads to an increase in their tensile strength and weld strength. The application of gas discharge pretreatment leads to an increase in the adhesion of polymer films to the polymer clay nanocomposite. The obtained results can be used to create multilayer flexible packaging materials with barrier properties, increased heat-welding ability and improved physical and mechanical characteristics. [ABSTRACT FROM AUTHOR]

It is frequently observed in field experiments that the eddy-covariance heat fluxes are systematically underestimated compared to the available energy, a phenomenon known as the surface energy balance (SEB) closure problem. A large-eddy simulation (LES) study is presented that investigates the behavior of turbulent organized structures (TOS) and their impact on the SEB closure problem. LES experiments are conducted for the daytime atmospheric boundary layer heated over a flat surface with atmospheric stability parameters - z i / L ranging from 8 to 130. Local imbalance is defined as the deviation of the 'observed' heat flux at a grid point from the regionally 'representative' heat flux; systematic imbalance is defined as the horizontally averaged local imbalance. A thorough analysis of the correlation between local imbalance and various local variables is conducted. Local imbalance exhibited the most significant correlation with the variance of potential temperature, implying its potential usefulness in parameterizing local imbalance. In characterizing the vertical variation of systematic imbalance, the spatial variances of mean vertical velocity and potential temperature play key roles. Results reveal that TOS induced a correlation between the mean vertical velocity and potential temperature in a horizontal space, resulting in systematic imbalance. The local imbalance is further contributed by the inhomogeneous distribution of the observed heat flux. Our results advance the understanding of the SEB closure problem and pave a possible way for the development of parameterization schemes. [ABSTRACT FROM AUTHOR]

There are increasing concerns about regional ecosystem shifts in the Arctic due to climate change. Notably, warming-induced increases in Arctic vegetation cover can have important consequences for surface energy balance, habitat changes, permafrost, and more. Mammalian herbivory is an important potential force to counteract this effect. In this systematic literature review, we examine the role of terrestrial mammalian herbivory on warming-induced increases in Arctic vegetation. We analyse the effects of terrestrial mammalian herbivory on vegetation cover, abundance, growth, survival, and ecosystem productivity. Our results show that herbivory has an overall significant negative influence on Arctic vegetation, particularly on vegetation biomass, growth, and productivity, as indicated by the Normalised Difference Vegetation Index (NDVI). Importantly, we demonstrated a significant role of herbivores in controlling carbon dioxide exchange and carbon uptake, whilst acknowledging that the relationship between herbivory and ecosystem productivity is highly complex and site-dependent. Our results confirm the important role that herbivory can play in buffering observed and predicted warming-induced Arctic vegetation increases. We also find that this is strongly affected by plant palatability, trampling occurrence, and herbivore density. [ABSTRACT FROM AUTHOR]

This article analyses the stability of thin-shell wormholes constructed from non-asymptotically flat wormholes and the vacuum Schwarzschild solution. The construction of these spherically symmetric thin shells focuses on a specific class of wormholes characterized by a shape function that is linearly dependent on the radial coordinate. This introduces angular defects, which can be either deficits or excesses in the solid angle. To analyze the stability of these structures, we employ linear perturbations around a static solution, using a master equation to describe the behavior of stable equilibrium regions. The study is systematically divided to examine both positive and negative surface energy densities, and it delves into various gravitational redshift functions. Finally, it is concluded that the interaction of an external force on the thin shell significantly influences the behaviour of stable regions. It is demonstrated that, in certain cases, the matter supporting the thin shell may be non-exotic, fully satisfying all energy conditions. [ABSTRACT FROM AUTHOR]

Accurate diagnosis of regional atmospheric and surface energy budgets is critical for understanding the spatial distribution of heat uptake associated with the Earth's energy imbalance (EEI). This contribution discusses frameworks and methods for consistent evaluation of key quantities of those budgets using observationally constrained data sets. It thereby touches upon assumptions made in data products which have implications for these evaluations. We evaluate 2001–2020 average regional total (TE) and dry static energy (DSE) budgets using satellite-based and reanalysis data. For the first time, a consistent framework is applied to the ensemble of the 5th generation European Reanalysis (ERA5), version 2 of modern-era retrospective analysis for research and applications (MERRA-2), and the Japanese 55-year Reanalysis (JRA55). Uncertainties of the computed budgets are assessed through inter-product spread and evaluation of physical constraints. Furthermore, we use the TE budget to infer fields of net surface energy flux. Results indicate biases < 1 W/m2 on the global, < 5 W/m2 on the continental, and ~ 15 W/m2 on the regional scale. Inferred net surface energy fluxes exhibit reduced large-scale biases compared to surface flux data based on remote sensing and models. We use the DSE budget to infer atmospheric diabatic heating from condensational processes. Comparison to observation-based precipitation data indicates larger uncertainties (10–15 Wm−2 globally) in the DSE budget compared to the TE budget, which is reflected by increased spread in reanalysis-based fields. Continued validation efforts of atmospheric energy budgets are needed to document progress in new and upcoming observational products, and to understand their limitations when performing EEI research. [ABSTRACT FROM AUTHOR]

This study uses an oceanic energy budget to estimate the ocean heat transport convergence in the North Atlantic during 2005–2018. The horizontal convergence of the ocean heat transport is estimated using ocean heat content tendency primarily derived from satellite altimetry combined with space gravimetry. The net surface energy fluxes are inferred from mass-corrected divergence of atmospheric energy transport and tendency of the ECMWF ERA5 reanalysis combined with top-of-the-atmosphere radiative fluxes from the clouds and the Earth's radiant energy system project. The indirectly estimated horizontal convergence of the ocean heat transport is integrated between the rapid climate change-meridional overturning circulation and heatflux array (RAPID) section at 26.5°N (operating since 2004) and the overturning in the subpolar north atlantic program (OSNAP) section, situated at 53°–60°N (operating since 2014). This is to validate the ocean heat transport convergence estimate against an independent estimate derived from RAPID and OSNAP in-situ measurements. The mean ocean energy budget of the North Atlantic is closed to within ± 0.25 PW between RAPID and OSNAP sections. The mean oceanic heat transport convergence between these sections is 0.58 ± 0.25 PW, which agrees well with observed section transports. Interannual variability of the inferred oceanic heat transport convergence is also in reasonable agreement with the interannual variability observed at RAPID and OSNAP, with a correlation of 0.54 between annual time series. The correlation increases to 0.67 for biannual time series. Other estimates of the ocean energy budget based on ocean heat content tendency derived from various methods give similar results. Despite a large spread, the correlation is always significant meaning the results are robust against the method to estimate the ocean heat content tendency. [ABSTRACT FROM AUTHOR]

Most research currently is limited to isotropic or porous materials reinforced by graphene platelets (GPLs). However, functionally graded materials (FGMs) made of two different material constituents offer many advantages in terms of durability, strength, high-temperature resistance, and design flexibility. Therefore, a new FGM model reinforced by GPLs (GPL-reinforced FGM) is proposed to enhance the performance of nanoplate structures. This paper presents analytical solutions for buckling and static bending problems of the GPL-reinforced FGM nanoplates with surface stress effects placed on a Pasternak elastic foundation. Three variation laws of the FGM (i.e., P-FGM, E-FGM, and S-FGM) combined with four GPL patterns (i.e., UD, FG-O, FG-X, and FG-V) are studied. The governing equations of the nanoplate resting on the elastic foundation are derived based on the principle of minimum total potential energy, Reddy's third-order shear deformation theory (TSDT), nonlocal strain gradient (NSG) theory (NSGT), and Gurtin–Murdoch surface elasticity theory (SET). The Navier technique is then utilized to determine the critical buckling load, deflection, and stress components of the nanoplate. The influence of material parameters, NSG parameters, surface energy parameters, and elastic foundation parameters on the static buckling and bending behaviors of the GPL-reinforced FGM nanoplate is investigated. [ABSTRACT FROM AUTHOR]

Durable superhydrophobic fabrics with electromagnetic wave absorption were highly valuable in practical applications. In this work, durable superhydrophobic cotton fabrics with electromagnetic wave absorption were successfully prepared by modifying the cotton fabrics with polydopamine (PDA) and then depositing MoS2/RGO (MR) composites and polydimethylsiloxane (PDMS). The surface morphology, crystal structure, and thermal degradation properties of the obtained products were evaluated. The PDA modification enhanced the affinity and adsorption saturation between the fabrics and the MR composites. Here, the MR composites provided the fabrics with wave-absorbing components and rough micro/nanostructure, and the PDMS offered lower surface energy for the treated fabrics. Ultimately, the water contact angle (WCA) of the obtained cotton fabrics could reach 157.2 ± 0.4 ° and the minimum reflection loss (RLmin) was −45.3 dB at 11.1 GHz, which showed excellent superhydrophobicity and microwave absorption properties. In addition, the obtained cotton fabrics displayed excellent robustness against rubbing, bending, and laundrying and satisfactory chemical stability. This research showed promising prospects for the development of wearable materials with durable electromagnetic wave absorption. [ABSTRACT FROM AUTHOR]

New methods for producing surfaces with suitable biocompatible properties are desirable due to increasing demands for biomedical devices. Stainless steel 316 L and cp- titanium specimens were coated with thin films of alumina and hafnia deposited using the atomic layer deposition method at two temperatures, 180 and 260 °C. The morphology of the films was analysed using scanning electron microscopy, and their surface energies were determined based on drop contact angle measurements. Biocompatibility assays performed using mesenchymal stem cells were evaluated by incubating the specimens and then exposing their extracts to the cells or directly seeding cells on the specimen surfaces. No detrimental effect was noticed for any of the specimens. Antibacterial properties were tested by directly incubating the specimens with the bacteria Staphylococcus aureus. Overall, our data show that all prepared films were biocompatible. Alumina films deposited on cp-titanium at 260 °C outperform the other prepared and tested surfaces regarding antiadhesive properties, which could be related to their low surface energy. [ABSTRACT FROM AUTHOR]

A highly sensitive, portable, rapid, and accurate colorimetric sensing method is presented. It is based upon exfoliated g-C3N4 nanosheets (E–g-C3N4 NSs), having peroxidase nanozyme-like properties. The as-prepared catalyst (E–g-C3N4 NSs) tends to oxidize the colorless tetramethyl-benzidine (TMB) into oxidized-TMB in the presence of hydrogen peroxide (H2O2) generating a dark blue color and corresponding ultraviolet visible-spectral changes following a Michaelis–Menten kinetic. The prepared colorimetric sensor exhibited response within the range 0.001–0.450 μM having R2 value of 0.999 and a detective limit (LOD) of 0.15 ± 0.04 nM. Furthermore, the sensor also displayed outstanding selectivity, ample stability (10 weeks), and excellent practicability in real sample applications. All these outstanding properties were highly attributed to the large surface area with exposed actives sites, high surface energy, and large conductive structure of E–g-C3N4 NSs. For comparison of the catalytic study, we have also explored the sensing mechanism of B-g-C3N4, using the same optimized experimental conditions. Resultantly, we concluded that the proposed sensor (E–g-C3N4 NSs) will gain considerable attention for on-site environmental and health monitoring in future endeavor. [ABSTRACT FROM AUTHOR]

The work describes one of the stages of development of flexible polymer gas sensors based on organic field-effect transistors (OFETs) and is devoted to revealing the dependencies of the electrical and sensory properties of these devices on the characteristics of the polymer dielectric layer of the OFETs. The influence of the material of the dielectric layer, as well as the conditions of its application to the polymer substrate were investigated. It was shown that the surface morphology and the properties of the semiconductor layer, which was formed on top of the polymer dielectric by thermal evaporation in vacuo, strongly depend on the value of the surface energy of the dielectric used, while the roughness of its layer has no considerable effect on the morphology. The highest electrical characteristics were demonstrated by the OFETs based on the dielectric with the highest value of surface energy, that is, polymethyl methacrylate. At the same time, regardless of the dielectric used, all the sensor devices demonstrate a high sensitivity towards nitrogen dioxide, which has values that are comparable to those characterizing the sensitivity of similar devices fabricated on silicon substrates using the studied dielectrics as interface layers, as well as an ability towards recovery of the starting properties in pure air that is higher compared to that of silicon samples, which is very promising for the commercial application of the developed polymer gas sensors. [ABSTRACT FROM AUTHOR]

This study establishes a finite element model based on the Iwan model to accurately characterize the force–displacement relationship and energy dissipation in bolted joints under small-amplitude tangential displacement. The force–displacement behavior of the Iwan model is transformed into a stress–strain relationship using a hybrid hardened intrinsic model. A subroutine developed with UMAT and UHARD is used to simulate the elastic–plastic behavior of the Iwan model during surface contact in the finite element model. Three-dimensional modeling and joint simulation are conducted using ABAQUS software. Experimental data verify the model's validity, and the effects of multiple factors on the bolted bonding surface are analyzed. The influence of friction coefficient, cyclic displacement amplitude, and preload on the force–displacement relationship of the bolted bonding surface is explored. Polynomial interpolation of the loading and unloading curves is applied to investigate the energy dissipation phenomenon. Results show that the finite element method can effectively reflect the hysteresis and energy dissipation behavior of the bonding surface. Increased friction coefficient and preload improve residual stiffness and energy dissipation capacity, while larger cyclic displacement amplitudes increase energy dissipation but have a minimal effect on residual stiffness. [ABSTRACT FROM AUTHOR]

The exceptional oil–water selectivity and low oil adhesion of hydrogel materials have garnered considerable attention within the realm of oil–water separation. In this paper, semi-interpenetrating polymer networks (semi-IPN) were introduced into polyvinyl alcohol (PVA)/polyacrylamide (PAM) hydrogels, which improved the mechanical properties of the hydrogels due to the presence of physical and chemical crosslinking. The incorporation of SiO2 nanoparticles into the hydrogel improved the surface energy and roughness, which resulted in superhydrophilic and underwater superoleophobic properties of PVA/PAM/SiO2 semi-IPN hydrogel-coated stainless-steel mesh (SSM). The SSM coated with hydrogel demonstrated excellent resistance to underwater oil, as evidenced by a contact angle of 156°. The oil–water separation flux was as great as 1.2 × 104 L m−2 h−1, and the separation efficiency exceeded 98%. Furthermore, PVA/PAM/SiO2 semi-IPN hydrogel-coated SSM is one of the best materials for solving oil–water separation issues due to its recyclability, self-cleaning properties, and stability under acidic and alkaline conditions. [ABSTRACT FROM AUTHOR]

Gluing polyolefins [e.g., polyethylene (PE) and polypropylene (PP)] results in a very challenging task. The main reason relies on their low surface energy, which reduces the affinity between the polyolefin surface and the chosen adhesive. To tackle this problem, the most commonly used solutions are physical surface treatments, such as plasma, corona, and flame, which introduce hydrophilic moieties on the plastics surface, thus increasing their surface energy. These approaches require special setups, are unspecific, and can induce material degradation. Furthermore, they provide a transient solution, making the storage of pretreated substrates not recommended. In this work, we developed an easy-to-apply primer for durable bonding of adhesives on PE and PP, as robust alternative to physical treatments. Our primer contains a surface-anchoring moiety and an adhesive-binding group to covalently react with the polyolefin substrate and with the glue. As a surface-anchoring moiety, we chose the perfluorophenylazide (PFPA), which is known to undergo a C–H insertion reaction upon UV activation, while as adhesive-binding groups, we selected OH functions, which can covalently react with the most common commercially available glues. When these two features (i.e., PFPA and OH) are combined in a single molecule, the reaction with the substrate does not occur and the molecule is only physisorbed, inducing no adhesion improvement. Chemisorption only occurs with bicomponent formulations, comprising a hydrophobic trifunctional PFPA and a polymer bearing OH and PFPA groups. Those induced improved adhesion on PP compared to the golden standard plasma with polyurethane-based and two-component epoxy adhesives. Storing the coated substrates at room temperature for up to two months did not alter the adhesion performance, thus further ascribing the developed primers as a promising alternative to plasma treatment. [ABSTRACT FROM AUTHOR]

In wide-bandgap semiconductor power device packaging, die bonding refers to attaching the die to substrate. Thereby, the process temperature of Ag sintering for the die bonding should be low to prevent damage to fragile dies. Herein, an organic-free strategy using Ag nanostructures derived from the thermal decomposition of metal–organic decomposition (MOD) was proposed to achieve low-temperature bonding. Significant effects on bonding performance were determined by the thermal decomposition temperature, which in turn determined the organic content and sintering degree of Ag nanostructures. At a low thermal decomposition temperature of 160 °C, incomplete decomposition resulted in high organic content in the Ag nanostructures, causing large pores inside the Ag joints owing to the generation of gaseous products. Owing to the Ag particles with naked surfaces and wide size distribution, the Ag nanostructure obtained at 180 °C showed an excellent bonding performance, resulting in a high shear strength of 31.1 MPa at a low bonding temperature of 160 °C. As the thermal decomposition temperature was 200 °C, sintering among Ag particles increased the particle size, resulting in a reduction of surface energy and driving force for sintering. We think that uncovering this underlying mechanism responsible for the bonding performance will promote the application of Ag MOD in the die bonding of WBG power devices. [ABSTRACT FROM AUTHOR]

To improve anti-icing traits of outdoor coatings, a synergy between photothermal and hydrophobic anti-icings was utilized to fabricate copolymer/Ti3C2Tx MXene composite coatings with good transparency and adhesion. MXene contributes to photothermal trait from local surface plasmon resonance effect. Copolymer enables hydrophobicity from perfluoroalkyls-induced low surface energy and high surface roughness. An increase in MXene dose results in an increased surface roughness. With 140.0 ± 2.2° of water contact angle and 70% of light transmittance, the optimal film bears 2 wt% of MXene. High MXene dose results in large temperature-increase of film under sunlight. After 15 min of sunlight exposure, the temperature of optimal film surface in icing simulation increases from − 18 ℃ to 7.2 ℃. After 48 h of acid immersion, the temperature-increase of optimal film surface based on 300 s of sunlight irradiation reaches 28.7 ± 1.2 ℃. After 48 h of ultraviolet irradiation, the temperature-increase of optimal film surface is 30.7 ± 0.8 ℃. This surface has a water contact angle of 132.7 ± 1.1° after 48 h of acid immersion. This study gives impetus to a preparation of various composite coatings for outdoor anti-icing/deicing. [ABSTRACT FROM AUTHOR]

The abnormal grain growth of high-purity cobalt during high-temperature annealing was analyzed in this work. The microstructure and orientation evolutions were characterized using the in situ electron backscatter diffraction technique. It was found that the HCP ↔ FCC phase transformation follows the orientation relationships of {0001}HCP//{111}FCC, < 11–20 > HCP// < 1–10 > FCC during both the heating and cooling process. At around 500 °C, the {100} oriented FCC grains exhibited abnormal growth, with the size exceeding 300 μm. The origin of this phenomenon was analyzed from the perspectives of grain orientation distribution and surface energy. The growth of {111} oriented grains is inhibited by the {111} texture, leading to the abnormal growth of {100} oriented grains, which have the second lowest surface energy. Additionally, the transformation microstructure of the abnormally large grains after cooling is analyzed. This work provides insights into the microstructure stability of high-purity cobalt sputtering targets during their service. [ABSTRACT FROM AUTHOR]

Robust, accurate, and direct measurements of evaporation and related energy fluxes on the Laurentian Great Lakes are necessary to understand the large historical range in water levels, regional climatology, lake hydrodynamics, and lake-effect snowfall, all of which inform water management. Despite the societal and scientific importance of this information, few long-term, full-year, in situ measurements exist due to logistical, financial, and safety-related challenges. We present 15 years (2008–2022) of eddy covariance data from Stannard Rock, a historic lighthouse on Lake Superior located 38 km southeast of Manitou Island and 72 km north of Marquette, Michigan. We provide information about the site and instrumentation, as well as data availability and processing. Analysis of this unique long-term dataset, available through the AmeriFlux network (US-GL1), will improve our ability to understand the drivers and patterns of large-lake surface energy fluxes and will advance predictions of evaporative regimes over Lake Superior. [ABSTRACT FROM AUTHOR]

The surface laser treatment of TiNi alloy by a Nd:YAG laser operating at a wavelength of 266 nm with different parameters (laser fluence 0.05–0.1 J/cm2, number of laser pulses 600-6000) is presented. Different analyses, including the study of surface morphology, free energy, roughness changes, phase composition, and surface chemistry are evaluated in relation to the wettability control of TiNi alloy. The results reveal a remarkable enhancement in hydrophilicity, evidenced by a sharp decrease in the water contact angle from 75.0 ± 5.1° to 11.4 ± 5.1°. This wettability improvement is positively correlated with the increased laser fluence and the number of laser pulses. The main contribution to the wettability alterations after laser treatment belongs to the surface saturation with oxygen and a subsequent formation of an oxide layer. This oxide layer significantly increases the polar component of the surface energy, thereby enhancing the hydrophilic properties of the TiNi alloy. [ABSTRACT FROM AUTHOR]

The surfaces of solids (gold, silver, and polymers) have been modified with adsorption layers of various compounds. Optimal modification conditions have been determined using the methods of contact angle measuring and quartz crystal microbalance. The degree of surface coverage with the adsorption layer has been calculated and the data obtained have been compared with the results of the direct measurements of adsorption. The surface energy of the modifying layers has been determined and the potential application fields of the modified solids as functional materials have been demonstrated. [ABSTRACT FROM AUTHOR]

Two mechanisms of the effect of the transition state of building particles (activated complexes, according to Arrhenius) on the crystal growth rate in the framework of the fluctuation model of dislocation growth are discussed. The transition state clusters adsorbed on the surface of a growing face act as an impurity lowering the crystal surface energy at instants between free energy fluctuations. Thus, the transition state of the crystallizing material, according to the first mechanism, affects the relaxation rate of the secondary adsorption of impurities and shortens the attachment time of building particles to the crystal face. Other clusters formed in solution reduce the number of free particles and, at low concentrations of the building material, may decrease the crystallization rate. Nevertheless, in a natural multicomponent crystallization environment, under the conditions of low building material concentration, essential thermal crystallization effect, and small deviations from equilibrium, the role of the transition state in the crystal growth is on the whole insignificant. [ABSTRACT FROM AUTHOR]

In this paper the size- and shape dependences of 8 different integral and partial molar thermodynamic quantities are derived for solid and liquid nano-phases, starting from the fundamental equation of Gibbs: i) The integral molar Gibbs energies of nano-phases and the partial molar Gibbs energies of components in those nano-phases, ii) The integral molar enthalpies of nano-phases and the partial molar enthalpies of components in those nano-phases, iii) The integral molar entropies of nano-phases and the partial molar entropies of components in those nano-phases, and iv). The integral molar inner energies of nano-phases and the partial molar inner energies of components in those nano-phases. All these 8 functions are found proportional to the specific surface area of the phase, defined as the ratio of its surface area to its volume. The equations for specific surface areas of phases of different shapes are different, but all of them are inversely proportional to the characteristic size of the phase, such as the diameter of a nano-sphere, the side-length of a nano-cube or the thickness of a thin film. Therefore, the deviations of all properties discussed here from their macroscopic values are inversely proportional to their characteristic sizes. The 8 equations derived in this paper follow strict derivations from the fundamental equation of Gibbs. Only the temperature dependent surface energy of solids and surface tension of liquids will be considered as model equations to simplify the final resulting equations. The theoretical equations are validated for the molar Gibbs energy against the experimental values of liquidus temperatures of pure lead. The theoretical equations for the molar enthalpy are validated i). Against the experimental values of dissolution enthalpy differences between nano- and macro cobalt particles in the same liquid alloy and ii). Against the size dependent melting enthalpy of nano-indium particles. In this way, also the theoretical equations for the molar entropy and molar inner energy are validated as they are closely related to the validated equations for the molar Gibbs energy and molar enthalpy. [ABSTRACT FROM AUTHOR]

Owing to its superior bulk mechanical properties, poly (ether ether ketone) (PEEK) has gained popularity over the past 15 years as a metal substitute in biomedical implants. Low surface energy is a fundamental issue with PEEK implants. This low surface energy caused by a moderately hydrophobic surface may be able to inhibit cellular adherence and result in the development of an inflammatory response, which may result in cell necrosis and apoptosis. In this work, plasma and ozone treatments have been utilized to surface activate PEEK and graft ionic bioactive polymer polyNaSS (poly (sodium styrene sulfonate)) successfully on the surface to promote cellular attachment and biomineralization. The main goal of our research has been to find a stable green process for surface modification of PEEK by plasma/ozone approaches to increase PolyNaSS grafting efficiency and biomineralization. To further the field of bioactive orthopedic and dental implant technology, this research attempts to address a significant constraint of PEEK implants while preserving their favorable mechanical properties. [ABSTRACT FROM AUTHOR]

Recent works have shown that in contrast to classical linear elastic fracture mechanics, endowing crack fronts in a brittle Green-elastic solid with Steigmann-Ogden surface elasticity yields a model that predicts bounded stresses and strains at the crack tips for plane-strain problems. However, singularities persist for anti-plane shear (mode-III fracture) under far-field loading, even when Steigmann-Ogden surface elasticity is incorporated. This work is motivated by obtaining a model of brittle fracture capable of predicting bounded stresses and strains for all modes of loading. We formulate an exact general theory of a three-dimensional solid containing a boundary surface with strain-gradient surface elasticity. For planar reference surfaces parameterized by flat coordinates, the form of surface elasticity reduces to that introduced by Hilgers and Pipkin, and when the surface energy is independent of the surface covariant derivative of the stretching, the theory reduces to that of Steigmann and Ogden. We discuss material symmetry using Murdoch and Cohen's extension of Noll's theory. We present a model small-strain surface energy that incorporates resistance to geodesic distortion, satisfies strong ellipticity, and requires the same material constants found in the Steigmann-Ogden theory. Finally, we derive and apply the linearized theory to mode-III fracture in an infinite plate under far-field loading. We prove that there always exists a unique classical solution to the governing integro-differential equation, and in contrast to using Steigmann-Ogden surface elasticity, our model is consistent with the linearization assumption in predicting finite stresses and strains at the crack tips. [ABSTRACT FROM AUTHOR]

Monitoring the defects generated during metal additive manufacturing is crucial for maintaining high manufacturing quality and extending the applications of this technology to various industries. In this study, balling defect generation was studied through the experimental investigation of directed energy deposition (DED) of Inconel 718 alloy on stainless steel. The relationships of deposition size and balling defects with audible sound were analyzed. Microelectromechanical systems microphones were installed around the Inconel 718 deposition spot to collect audible sound signals. Moreover, a high-speed optical camera and a thermal camera were used to collect real-time optical and thermal images, respectively, during deposition. The results of this study indicate that the surface energy of the liquid metal in DED has a crucial effect on the geometry of the melt pool. The accumulation of melt material because of the surface energy causes a shift in the deposition position away from the front edge of previously deposited material and is the primary factor causing balling defects. Sound signal analysis confirmed strong correlations between the features of audible sound and the melt volume in single-point deposition experiments. The relationships between the features of audible sound and balling defects were also determined. The time and frequency features of collected audible sound signals can be used to identify the generation of balling defects in the DED of Inconel 718. [ABSTRACT FROM AUTHOR]

We propose an efficient method with energy constraints for constructing a Catmull–Clark surface that interpolates a given mesh. We approximate the surface energy of Catmull–Clark surfaces near extraordinary points by summing their finite subpatches and then represent the energy of the subpatches as linear combinations of the vertices of control mesh. By minimizing the surface energy as a constraint, we generate a new control mesh whose limit surfaces interpolate a given mesh. Numerous examples and comparisons demonstrate that our method has the following characteristics: (1) The limit surfaces are fairer, reducing unnecessary undulations and having minimal surface energy, and (2) the approximation process is simple and intuitive, requiring only a small number of computational steps and avoiding complex parameterization processes. [ABSTRACT FROM AUTHOR]

To study the interfacial properties of Ag/In2O3, the interfacial binding energy, interfacial adhesion work, and interfacial electronic properties of Ag/In2O3 were calculated based on the first principles of density functional theory. The results show that the surface energy of 50 layers of In2O3 (110)-O and 48 layers of In2O3 (111)-O is small and the surface is stable. Ag(111) surface thickness of 10 layers is the most stable, based on which the Ag/In2O3 interface is established. In the established Ag/In2O3 interface, the Ag(111)/In2O3(110)-O interface has good stability, high interface bonding strength, and metallic characteristics. When the interface spacing is 3.0 Å, the interface stability is good. The charge redistribution at the interface results in the change of the density of the local atomic states, in which the change of Ag and O atoms is more obvious. In addition, the Ag/In2O3 interface is mainly bound by ionic bonds, and the interface part is well bound. [ABSTRACT FROM AUTHOR]

In order to improve the infiltration and adhesion of epoxy resin to CFs and enhance the interfacial properties of CFs/EP composites, the water-soluble epoxy resin prepared by in-situ blending phosphorylation modification was compounded into a high-temperature-resistant carbon fiber sizing agent, and the CFs/EP composites were prepared by vacuum-assisted resin transfer forming method. The results showed that the prepared sizing agent contained epoxy resin, aliphatic ester, polyoxyethylene and other active oxygen-containing groups. It had good water solubility, small particle size, good stability, and could be dissolvable with water at room temperature in any proportion. The average particle size of 1% sizing agent emulsion was 17.7 nm, and it was stable at 4000 rpm for 30 min. The initial decomposition temperature of the sizing agent is 313 ℃, the mass residue rate is 65.60% at 400 ℃, and the mass residue is 20% at 600 ℃, which has excellent high-temperature resistance. The sizing agent can also significantly improve the surface energy of CFs, and increase its surface interface bonding and mechanical properties. When the content of sizing agent on the surface of CFs is 7.88 mg/g, the surface energy is 47.38 mN/m, and the breaking strength is 777.91 MPa, which is 24.42 and 29.29% higher than that of desizing CFs. The bend strength and shearing strength of the prepared CFs/EP composites are 107.38 MPa and 9.83 MPa, which are increased by 81.91 and 20.17% compared with the desizing products. [ABSTRACT FROM AUTHOR]

The impact and adhesion mechanics of two-phase block copolymers during high-velocity impacts are studied experimentally and computationally to understand the effect of the rubbery phase on bonding behavior in cold spray additive manufacturing. Micron-scale (10-20 μm) spherical particles of polystyrene-block-polydimethylsiloxane with varying rubbery phases are impacted on a silicon substrate by using a laser-induced projectile impact test setup with impact velocities in the range of 50-600 m/s. Experiments indicate that the minimum impact velocity for polymer particles adhering to the substrate decreases with increasing rubbery phase content. A strain rate- and temperature-dependent constitutive model and cohesive zone model are calibrated for each material by comparing the deformed and computed deformed particle shapes and coefficient of restitution values of the rebounding particles. Computational results show that increasing the rubbery phase content in block copolymers increases plastic energy dissipation from 89 to 96% and the critical strain energy release rate from 1.87 to 9.3 J/m2 at 140 m/s, and thus contributes to the observed decrease in the minimum impact velocity required for block copolymers to adhere to substrates. The discovered direct relationship between soft phase content and critical strain energy release rate implies that increased soft-rubbery PDMS content in block copolymers enhances adhesion through improved chain mobility, better surface asperities coverage, and enhanced wetting, due to its lower surface energy and greater adiabatic heating. [ABSTRACT FROM AUTHOR]

Rubber tire mold fouling is a severe problem leading to mold surface corrosion, tire defects, and extra energy consumption. Traditional mechanical and chemical cleaning is inefficient and induces mold surface damage. Low surface energy organic coating displays antiadhesive behavior but is susceptible to wear. Here, we develop a bioinspired Co-CeO2/MoS2 coating with effective mechanical robustness, corrosion resistance, and antifouling behavior by leveraging a slippery liquid-infused surface (SLIPS) strategy. The micro-nanostructure of the coating serves as mechanical stability and anticorrosion skeleton with the infused lubricant acting as a slippery antifouling surface. The variation of microstructure, mechanical strength, corrosion resistance, and antifouling behavior of the coating with individual and synergistic addition of CeO2 and MoS2 is systematically characterized. The slippery Co-CeO2/MoS2 coating shows excellent mechanical stiffness, corrosion resistance, and antifouling performances in rubber vulcanization conditions. [ABSTRACT FROM AUTHOR]

Owing to its high production volume and wide range of applications, polyethylene has gained a great deal of attention, but its low surface energy and non-polar nature have limited its application in some important fields. In this study, ethylene/11-iodo-1-undecene copolymers were prepared and used as the intermediates to afford a series of imidazolium-based ionomers bearing methanesulfonate (CH3SO3−), trifluoromethanesulfonate (CF3SO3−), or bis(trifluoromethane)sulfonimide (Tf2N−) counteranions. The tensile test results showed that the stress-at-break (7.8–25.6 MPa) and the elongation-at-break (445%–847%) of the ionomers could be adjusted by changing the counterion species and the ionic group contents. Most importantly, the ionomers exhibited marvelous antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The ionomers bearing Tf2N− exhibited antibacterial activities >99% against both S. aureus and E. coli when ionic content reached 9.1%. The imidazolium-based ionomers prepared in this work demonstrated excellent comprehensive properties, especially high-efficient and broad-spectrum antibacterial ability, exhibiting the potential for the application as the antibacterial materials in packaging, medical, and other fields. [ABSTRACT FROM AUTHOR]

The impact of film thickness and annealing temperature on the structural, electrical, magnetic, and mechanical properties of cobalt–iron–dysprosium (Co40Fe40Dy20) thin films deposited on Si(100) substrates have been investigated. X-ray diffraction (XRD) analysis confirmed the film's crystalline microstructure, featuring dysprosium oxide, Dy2O3(440), and cobalt oxide, Co2O3(422) and Co2O3(511), crystallographic phases. Surface energy measurements indicated a noticeable reduction in surface energy following annealing treatments, which could be ascribed to the alleviation of residual stress and enhanced atomic arrangement, resulting in a more stable film structure with reduced surface energy. The film exhibited a decreasing trend in hardness with increasing thickness, and film resistivity was significantly responsive to alterations in thickness and annealing temperature. Notably, the Co40Fe40Dy20 film demonstrated exceptional characteristics, featuring a high saturation magnetization (Ms) of 675 emu/cm3 and a low coercivity (Hc) of 9.5 Oe. Further analysis of magnetic domains and hysteresis loops revealed that larger and brighter domains were associated with higher Hc. To sum up, the surface roughness of CoFeDy films under various annealing temperatures played a pivotal role in shaping their magnetic, electrical, adhesive, and optical characteristics. An improved low-frequency alternating current magnetic susceptibility (χac) value was achieved by minimizing the pinning effect on domain walls through surface smoothing. Moreover, smoother surfaces displayed heightened carrier conductivity, resulting in a decrease in electrical resistance. On the whole, Co40Fe40Dy20 films exhibited outstanding soft magnetic properties, encompassing high saturation magnetization, low coercivity, exceptional mechanical attributes, and decreased surface energy. [ABSTRACT FROM AUTHOR]

Surface-modified bacterial cellulose, namely, BC-g-PMMA fiber, was synthesized by graft polymerization. The BC-g-PMMA fiber was employed as a surface modifying agent for a porous polylactic acid (PLA) scaffold, which was prepared through phase inversion. In this study, BC-g-PMMA 1:1 (BC: MMA mole ratio of 1:1), BC-g-PMMA 1:3 (BC: MMA mole ratio of 1:3), and BC-g-PMMA 1:6 (BC: MMA mole ratio of 1:6) were prepared using methyl methacrylate (MMA) as a grafting monomer under sonication-assisted reactions. Various characterization methods, including FTIR, DSC, and TGA, were employed to confirm that BC-g-PMMA exhibited an amphiphilic structure. Next, the PLA/BC-g-PMMA composite scaffold was successfully prepared using a solvent-induced phase inversion technique involving a solvent exchange step (dioxane diffused out while water diffused in); due to this process, the honeycomb structure of the PLA/BC-g-PMMA composite contained amphiphilic surfaces, and the wettability and cell adhesion behavior of the porous material were manipulated. In the absence of BC-g-PMMA, porous PLA exhibited a hydrophobic surface and no wicking properties. In contrast, the PLA/BC-g-PMMA composites showed an ability to wick, which was related to the grafted PMMA moiety; the higher the grafted PMMA ratio was, the slower the wicking ability due to the decrease in the surface energy of the composites. Due to their tailored surface chemistry, these materials played a role in the adherence of the composites to proteins and human gingival fibroblasts. Therefore, amphiphilic spongy PLA/BC-g-PMMA composites are promising materials for tissue engineering and spheroid (3D cell structure) scaffolds. [ABSTRACT FROM AUTHOR]

The Hamaker constants are calculated for the PTFE/PTFE, PTFE/tetradecane, and PTFE/water (PTFE is polytetrafluoroethylene) systems using various dielectric models. Selection of the dielectric model significantly affects the absolute values of the Hamaker constants while it has virtually no effect on their relative changes depending on the density and dielectric increment of PTFE. The total calculated changes in the work of adhesion due to van der Waals interactions, taking into account changes in density and dielectric increment in gamma-irradiated PTFE, do not exceed 11% for all dielectric models used. It is concluded that changes in surface energy upon the irradiation of PTFE cannot be explained solely by an increase in the contribution of the van der Waals interaction due to polar radiolysis products. It is necessary to consider the electrostatic interaction of stabilized charges with the dipoles of a polar liquid. [ABSTRACT FROM AUTHOR]

We consider a sharp interface formulation for the multi-phase Mullins–Sekerka flow. The flow is characterized by a network of curves evolving such that the total surface energy of the curves is reduced, while the areas of the enclosed phases are conserved. Making use of a variational formulation, we introduce a fully discrete finite element method. Our discretization features a parametric approximation of the moving interfaces that is independent of the discretization used for the equations in the bulk. The scheme can be shown to be unconditionally stable and to satisfy an exact volume conservation property. Moreover, an inherent tangential velocity for the vertices on the discrete curves leads to asymptotically equidistributed vertices, meaning no remeshing is necessary in practice. Several numerical examples, including a convergence experiment for the three-phase Mullins–Sekerka flow, demonstrate the capabilities of the introduced method. [ABSTRACT FROM AUTHOR]

Laponite® (Lap) is a synthetic layered nanoclay that is considered a potential candidate for improving the physicochemical properties of gelatin films. However, there is limited information in the literature about the interaction between Lap platelets and gelatin chains and its impact on the physicochemical film properties. Therefore, the current research aimed to systematically study the mechanism of interaction and the effect of Lap on the physicochemical properties of gelatin films (moisture content, optical properties, water contact angle, surface energy, water adsorption, water solubility, water vapor permeability, and mechanical properties). Furthermore, gelatin films with Lap were applied as UV-barrier materials in grape juice. Gelatin films were produced by casting method containing 0, 3, 5, 10, and 15% of Lap (based on the weight of the biopolymer). The incorporation of Lap reduced the formation of the gelatin triple helix structure and consequently film crystallinity. Hydrogen bonds and electrostatic interactions could be the principal interactions between gelatin/glycerol/Lap. The incorporation of Lap increased the thickness and moisture content. Lap platelets were completely exfoliated and did not modify the color and opacity of the gelatin films. The UV-barrier capacity of the gelatin films was improved with the incorporation of Lap. Gelatin films with 15% Lap exhibited a transmittance decreases of 86% and 5% in ultraviolet (280 nm) and visible (470 nm) light, respectively. Furthermore, a reduction of 29% in film water solubility was observed with 15% Lap. Other properties such as water contact angle, surface free energy, water vapor permeability, and mechanical properties were not modified by the incorporation of Lap. Gelatin films containing Lap (15%) reduced the degradation of anthocyanins (50%) in grape juice exposed to UV light when compared with samples covered with gelatin films without Lap. [ABSTRACT FROM AUTHOR]

A geometrically symmetric gear with asymmetric surface wettability exhibits one-way spin on a vibrating water bed. On the side face of the gear, a parafilm was coated to create asymmetry in the surface energy. The gear shows fluctuations in both directions within a shorter timescale; however, for a longer timescale, the gear exhibits a one-way spin. This unique motion is generated by a stochastic process with a biased driving force produced by the interaction between the vibrating water surface and the side face of the gear. This new model resembles an active Brownian ratchet. Until now, most ratchet motors, which obtain regular motion from nonthermal fluctuations, utilize a geometrical ratchet structure. However, in this study, the surface energy forms a ratchet that rectifies the noisy motion. [ABSTRACT FROM AUTHOR]

This work presented a novel method for fabricating corrosion-resistant and fluorine-free superhydrophobic Al2O3/nickel hydroxide (NiOxHy)/stearic acid (STA) composite coating on the Al alloys. The Al2O3/NiOxHy composite film with an ideal micro-nanostructure was assembled on Al alloys by a one-step anodizing method. This facile and low-cost technique for fabricating superhydrophobic coating includes high-temperature anodizing in oxalic acid aqueous solution with Ni2+ and subsequent spin coating of the STA layer. The superhydrophobicity of as-fabricated film results from the hierarchical micro-nanostructure of Al2O3/NiOxHy and the coverage of STA with low surface energy, while the micro-nanostructure is beneficial to providing the appropriate roughness and maintaining more STA in its interstices and surface. The Al alloys with an optimal superhydrophobic coating displayed a static water contact angle of 164°, excellent self-cleaning ability, and superb corrosion-resistant efficiency of 99.6%. This facile method offers an effective strategy to fabricate corrosion-resistant protective coating on metallic substrates, which can significantly prolong the working lifetime of metallic materials in harsh environments. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study is to evaluate the bond strength of different computer-aided design / computer-aided manufacturing (CAD/CAM) hybrid ceramic materials following different pretreatments. Methods: A total of 306 CAD/CAM hybrid material specimens were manufactured, n = 102 for each material (VarseoSmile Crownplus [VSCP] by 3D-printing; Vita Enamic [VE] and Grandio Blocs [GB] by milling). Each material was randomly divided into six groups regarding different pretreatment strategies: control, silane, sandblasting (50 μm aluminum oxide particles), sandblasting + silane, etching (9% hydrofluorics acid), etching + silane. Subsequently, surface roughness (Ra) values, surface free energy (SFE) were measured. Each specimen was bonded with a dual-cured adhesive composite. Half of the specimens were subjected to thermocycling (5000 cycles, 5–55 °C). The shear bond strength (SBS) test was performed. Data were analyzed by using a two-way analysis of variance, independent t-test, and Mann-Whitney-U-test (α = 0.05). Results: Material type (p = 0.001), pretreatment strategy (p < 0.001), and the interaction (p < 0.001) all had significant effects on Ra value. However, only etching on VSCP and VE surface increased SFE value significantly. Regarding SBS value, no significant difference was found among the three materials (p = 0.937), while the pretreatment strategy significantly influenced SBS (p < 0.05). Etching on VSCP specimens showed the lowest mean value among all groups, while sandblasting and silane result in higher SBS for all test materials. Conclusions: The bond strength of CAD/CAM hybrid ceramic materials for milling and 3D-printing was comparable. Sandblasting and silane coupling were suitable for both millable and printable materials, while hydrofluoric etching should not be recommended for CAD/CAM hybrid ceramic materials. Clinical relevance: Since comparable evidence between 3D-printable and millable CAD/CAM dental hybrid materials is scarce, the present study gives clear guidance for pretreatment planning on different materials. [ABSTRACT FROM AUTHOR]