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This study introduces a novel meter-scale dielectric barrier discharge (m-DBD) reactor designed to generate large-scale, low-temperature nanosecond pulsed discharge plasma. By employing a modularized gas path, this reactor enables a comprehensive analysis of discharge patterns and uniformity using multi-dimensional discharge parameters. Simulation results reveal optimal gas distribution with ten gas holes in the variable plate and a 40 mm slit depth in the main reactor. Besides, a diagnosis method based on electro-acoustic-spectrum-image (E-A-S-I) parameters is developed to evaluate nanosecond pulsed m-DBD discharge states. It is found that the discharge states are closely related to the consistency of segmental discharge currents, the fluctuation of acoustic signals and the distribution of active particles. Machine learning methods are established to realize the diagnosis of m-DBD discharge pattern and uniformity by E-A-S-I parameters, where the optimized BPNN has a best recognition accuracy of 97.5%. Furthermore, leveraging nanosecond pulse power in Ar/m-DBD enables stable 1120 × 70 mm2 discharge, uniformly enhancing hydrophobicity of large-scale materials from a 67° to 122° water contact angle with maximal fluctuations below 7%. The modularized m-DBD reactor and its intelligent analysis based on multi-dimensional parameter provide a crucial foundation for advancing large-scale nanosecond pulsed plasma and their industrial applications. [ABSTRACT FROM AUTHOR]

Nanofluids have excellent lubrication and high thermal conductivity. However, the agglomeration and sedimentation produced by the large surface energy of nanoparticles in base liquid threaten the long-term dispersion stability and impact the wide application of nanofluid. In this work, based on the self-assemble behavior and continuous network structure formed by low molecular weight organic gelator, the uniform clusters were formed through regulating the kinetics behavior in the gelling process. The dragging effect was demonstrated by oleic acid - sodium dodecyl sulfate (OA-SDS) bicomponent gelator and graphene oxide (GO) nanosheets. The results showed that GO nanofluids dispersed by OA-SDS were stable for more than 12 months. The well-dispersed GO nanofluid exhibited better anti-friction and anti-wear properties under both immersion and electrostatic minimum quantity lubrication conditions. Moreover, the lower contact angle, surface tension and droplet size of nanofluids after charging improved the wettability on the frictional interface. The GO adsorption film formed on the friction interface protected the tribochemical reaction film of iron oxide and prevented the occurrence of sintering of base oil. [ABSTRACT FROM AUTHOR]

Electrohydrodynamic-jet printing (E-jet printing) is a direct-writing technology for manufacturing micro-nano devices. To further reduce the inner diameter of the nozzle to improve the printing resolution, a large-scale manufacturing method of SU-8 polymer micro/nanoscale nozzle by means of a process combining UV exposure and hot embossing was proposed. To improve the adhesive strength between the UV mask and SU-8, the influence of the oxygen plasma treatment parameters on the water contact angles of the UV mask was analyzed. The effect of hot embossing time and temperature on the replication precision was studied. The influence of UV exposure parameters and thermal bonding parameters on the micro and nanochannel pattern was investigated. The SU-8 polymer nozzles with 188 ± 3 nm wide and 104 ± 2 nm deep nanochannels were successfully fabricated, and the replication precision can reach to 98.5%. The proposed manufacturing method of SU-8 polymer nozzles in this study will significantly advance the research on the transport properties of nanoscale channels in E-jet nozzles and facilitate further advancements in E-jet based applications. [ABSTRACT FROM AUTHOR]

With the continuous development of society, the discharge of oily wastewater in daily life and industry has gradually increased, causing considerable damage to the environment, and how to effectively treat oily wastewater is an urgent problem. In this paper, a simple method is proposed to prepare superhydrophobic stainless steel mesh with pH response. The relationship between the ratio of mixed thiols and the surface wettability was explored, as well as the morphology, chemical composition, and pH-responsive mechanism of the stainless steel mesh surface were analyzed, and the separation efficiency, recycling ability, and backwashing ability of the mesh were explored by oil–water separation experiments. It was found that when the molar fraction of 11-mercaptoundecanoic acid and 1-decanethiol in the mixed mercaptan was 2:3, the water contact angle of the surface at this point was 156.5 ± 1°, with pH response characteristics and good oil–water separation efficiency, backwashing and recycling capabilities. [ABSTRACT FROM AUTHOR]

We report on the formation of bendable and edge-on poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CT) polymers thin layer used as a hole modification layer (HML) in the inverted perovskite solar cell. The aggregations of 2D layer-like P3CT polymers in dimethylformamide (DMF) solution can be formed via aromatic π – π stacking interactions and/or hydrogen-bonding interactions with the different concentration from 0.01 to 0.02 wt%, which highly influences the photovoltaic performance of the inverted perovskite solar cells. The atomic-force microscopic images and water droplet contact angle images show that the P3CT polymers modify the surface properties of the transparent conductive substrate and thereby dominating the formation of perovskite crystalline thin films, which play important roles in the highly efficient and stable perovskite solar cells. It is noted that the V OC (J SC) of the encapsulated solar cells values are maintained to be higher than 1.115 V (22 mA cm−2) after 104 d when an optimized π – π stacked and hydrogen-bonded P3CT polymer is used as the HML. On the other hand, the solar cell showed a high long-term stability by maintaining 85% of the initial power conversion efficiency in the ambient air for 103 d. [ABSTRACT FROM AUTHOR]

Electrically actuated linear motion of a water droplet over PDMS-coated single active electrode is analyzed from detailed experiments and modeling. In an experiment, continuous motion of the droplet is achieved when it is located over an active electrode with a horizontal ground wire placed just above in an open-electrowetting-on-dielectric configuration. Using a CCD camera, the instantaneous centroid position of the droplet is determined and its velocity is inferred by numerical differentiation. The edge-detected image is also used to determine the advancing and receding contact angles of the moving drop relative to the substrate. Motion of 2, 6, and 10 µ l water droplets for voltages in the range of 170–270 V DC is examined to investigate the effect of drop volume and voltage on drop deformation and velocity. The motion of the droplet is initiated by Young-Lippmann spreading at the three-phase contact line, followed by a nonuniform electric force field distributed between the active electrode and the ground wire localized at the droplet-air interface. Simulations carried out using COMSOL© Multiphysics with full coupling between the electric field and hydrodynamics are in conformity with experiments. A contact angle model with pinning and friction leads to close agreement between simulations and drop motion over a bare PDMS layer, particularly in terms of the relevant timescales. When contact line friction is neglected, the fully coupled numerical solution shows a good match with experimentally determined drop movement over a silicone oil-coated PDMS layer. Over both surfaces, continuous motion of the water droplet is seen to be achieved in three stages, namely, initial spreading, acceleration, and attainment of constant speed. [ABSTRACT FROM AUTHOR]

Morphology and wettability of dielectric layers are crucial properties that affect the electrowetting-on-dielectric (EWOD) performance of a working liquid. In this work, the use of a poly(vinyl chloride) (PVC) microfiber-modified PVC dielectric layer as an electrowetting-on-dielectric (EWOD) substrate is explored. Imaging with scanning electron and atomic force microscopy revealed intertwined microfibers on the original PVC film after PVC deposition via electrospinning. Hydrophobicity of the PVC layer was enhanced by the presence of microfibers, with the contact angle (CA) for a water droplet increasing from 84.9° to 123.9°. EWOD behavior of various liquids on the microfiber-modified PVC layer was investigated within a DC voltage range of 0 to 200 V DC. Gold nanofluid exhibited the largest change in CA of 57°, while smaller changes were observed for KOH (19.6°), KCl (21.2°), and water (21°). A mechanism explaining the observed reduction in contact angle for a gold nanofluid droplet is presented. Our results suggest the promising potential of PVC film-PVC microfiber as a hydrophobic dielectric material for EWOD applications involving diverse liquids, including gold nanofluids.

The adsorption dynamics of double-stranded DNA (dsDNA) molecules on a graphene oxide (GO) surface are important for applications of DNA/GO functional structures in biosensors, biomedicine and materials science. In this work, molecular dynamics simulations were used to examine the adsorption of different length dsDNA molecules (from 4 bp to 24 bp) on the GO surface. The dsDNA molecules could be adsorbed on the GO surface through the terminal bases and stand on the GO surface. For short dsDNA (4 bp) molecules, the double-helix structure was partially or totally broken and the adsorption dynamics was affected by the structural fluctuation of short dsDNA and the distribution of the oxidized groups on the GO surface. For long dsDNA molecules (from 8 bp to 24 bp) adsorption is stable. By nonlinear fitting of the contact angle between the axis of the dsDNA molecule and the GO surface, we found that a dsDNA molecule adsorbed on a GO surface has the chance of orienting parallel to the GO surface if the length of the dsDNA molecule is longer than 54 bp. We attributed this behavior to the flexibility of dsDNA molecules. With increasing length, the flexibility of dsDNA molecules also increases, and this increasing flexibility gives an adsorbed dsDNA molecule more chance of reaching the GO surface with the free terminal. This work provides a whole picture of adsorption of dsDNA molecules on the GO surface and should be of benefit for the design of DNA/GO based biosensors. [ABSTRACT FROM AUTHOR]

The interfacial adhesion energy between graphene and underlying substrates is considerably important for robust graphene biosensors because water molecules can intercalate underneath graphene when submerged, possibly detaching graphene from substrates. This study investigated the robustness of graphene field-effect transistor arrays fabricated on hydrophobic and hydrophilic SiO2 substrates. Although the graphene sheets delaminated from hydrophilic substrates within minutes of submersion in a buffer solution, they remained stable on hydrophobic substrates for several days. This result agreed with the estimated thermodynamic work of adhesion in water, which improved significantly from âˆ'17.3 to 17.7 mJ mâˆ'2 through the hydrophobization process of the substrates. [ABSTRACT FROM AUTHOR]

Silicon (Si) anodes are promising candidates for Li-ion batteries due to their high specific capacity and low operating potential. Implementation has been challenged by the significant Si volume changes during (de)lithiation and associated growth/regrowth of the solid electrolyte interphase (SEI). In this report, fluorinated local high concentration electrolytes (FLHCEs) were designed such that each component of the electrolyte (solvent, salt, diluent) is fluorinated to modify the chemistry and stabilize the SEI of high (30%) silicon content anodes. FLHCEs were formulated to probe the electrolyte salt concentration and ratio of the fluorinated carbonate solvents to a hydrofluoroether diluent. Higher salt concentrations led to higher viscosities, conductivities, and contact angles on polyethylene separators. Electrochemical cycling of Si-graphite/NMC622 pouch cells using the FLHCEs delivered up to 67% capacity retention after 100 cycles at a C/3 rate. Post-cycling X-ray photoelectron spectroscopy (XPS) analyses of the Sigraphite anodes indicated the FLHCEs formed a LiF rich solid electrolyte interphase (SEI). The findings show that the fluorinated local high concentration electrolytes contribute to stabilizing the Si-graphite electrode over extended cycling. [ABSTRACT FROM AUTHOR]

We consider the thin-film equation ∂ t h + ∂ y m (h) ∂ y 3 h = 0 in { h > 0} with partial-wetting boundary conditions and inhomogeneous mobility of the form m (h) = h 3 + λ 3âˆ' n h n , where h â©ľ 0 is the film height, λ > 0 is the slip length, y > 0 denotes the lateral variable, and n ∈ (0, 3) is the mobility exponent parameterizing the nonlinear slip condition. The partial-wetting regime implies the boundary condition ∂ y h = const. > 0 at the triple junction ∂{ h > 0} (nonzero microscopic contact angle). Existence and uniqueness of traveling-wave solutions to this problem under the constraint ∂ y 2 h â†' 0 as h â†' ∞ have been proved in previous work by Chiricotto and Giacomelli (2011 Commun. Appl. Ind. Math. 2 e-388, 16). We are interested in the asymptotics as h â†" 0 and h â†' ∞. By reformulating the problem as h â†" 0 as a dynamical system for the difference between the solution and the microscopic contact angle, values for n are found for which linear as well as nonlinear resonances occur. These resonances lead to a different asymptotic behavior of the solution as h â†" 0 depending on n. Together with the asymptotics as h â†' ∞ characterizing the Coxâ€"Voinov law for the velocity-dependent macroscopic contact angle as found by Giacomelli, the first author of this work, and Otto (2016 Nonlinearity 29 2497â€"536), the rigorous asymptotics of traveling-wave solutions to the thin-film equation in partial wetting can be characterized. Furthermore, our approach enables us to analyze the relation between the microscopic and macroscopic contact angle. It is found that the Coxâ€"Voinov law for the macroscopic contact angle depends continuously differentiably on the microscopic contact angle. [ABSTRACT FROM AUTHOR]

Attachment of biorecognition molecules prior to microfluidic packaging is advantageous for many silicon biosensor-based lab-on-a-chip (LOC) devices. This necessitates biocompatible bonding of the microfluidic cartridge, which, due to thermal or chemical incompatibility, excludes standard microfabrication bonding techniques. Here, we demonstrate a novel processing approach for a commercially available, two-step curable polymer to obtain biocompatible ultraviolet initiated (UVA)-bonding of polymer microfluidics to silicon biosensors. Biocompatibility is assessed by UVA-bonding to antibody-functionalized ring resonator sensors and performing antigen capture assays while optically monitoring the sensor response. The assessments indicate normal biological function of the antibodies after UVA-bonding with selective binding to the target antigen. The bonding strength between polymer and silicon chips (non-biofunctionalized and biofunctionalized) is determined in terms of static liquid pressure. Polymer microfluidic cartridges are stored for more than 18 weeks between cartridge molding and cartridge-to-silicon bonding. All bonded devices withstand more than 2500 mbar pressure, far exceeding the typical requirements for LOC applications, while they may also be de-bonded after use. We suggest that these characteristics arise from bonding mainly through intermolecular forces, with a large extent of hydrogen bonds. Dimensional fidelity assessed by microscopy imaging shows less than 2% shrinkage through the molding process and the water contact angle is approximately 80°. As there is generally little absorption of UVA light (365 nm) in proteins and nucleic acids, this UVA-bonding procedure should be applicable for packaging a wide variety of biosensors into LOC systems. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) is widely used to elaborate biomaterials and medical devices in particular for long-term implant applications but tuning their surface properties remains challenging. We investigate surface functionalization by grafting poly(sodium 4-styrene sulfonate, PNaSS) with the aim of enhancing protein adhesion and cellular activity. Elucidating the topography and molecular level organization of the modified surfaces is important for understanding and predicting biological activity. In this work, we explore several grafting methods including thermal grafting, thermal grafting in the presence of Mohr’s salt, and UV activation. We characterize the different surfaces obtained using atomic force microscopy (AFM), contact angle (CA), and x-ray photoelectron spectroscopy (XPS). We observe an increase in the percentage of sulfur atoms (XPS) that correlates with changes in (CA), and we identify by AFM characteristic features, which we interpret as patches of polymers on the PET surfaces. This work demonstrates tuning of biomaterials surface by functionalization and illustrates the capability of AFM to provide insights into the spatial organization of the grafted polymer. [ABSTRACT FROM AUTHOR]

Quantum dot (QD) features many exceptional optical performances but is also vulnerable to moisture which results in structural damage and luminescent decrease. This work provided and fabricated a novel superior hydrophobic methylated core/shell silica-coated QD (MSQ) for high water stability. QD was coated with a silica shell and then surface-methylated by trimethyl silane. Mercaptopropyl trimethoxy silane, tetraethyl orthosilicate, and ethoxy trimethyl silane were utilized as the ligand exchanger, the raw material of silica, and the surface modification, respectively. Characterization results illustrated the core/shell structure of MSQ. In addition, its water contact angle was up to 159.6°. QD-, silica-coated QD(SQ)-, and MSQ-silicone were made and displayed similar absorption, emission, and excitation spectra but different water stabilities. The photoluminescence intensity and photoluminescence quantum yield of MSQ-silicone hardly changed during 15 d of water immersion, in contrast to the dramatical decrease of other two kinds of composite silicone. Specifically, the photoluminescence quantum yield decreases of MSQ-, SQ-, and QD-silicone were 1%, 40%, and 43%, respectively. Therefore, MSQ had a much better water stability. The superior hydrophobic methylated silica-coated QD has a great potential to realize the long-term working stability in a humid environment and the wider application in diverse fields. [ABSTRACT FROM AUTHOR]

Bright white plasma electrolytic oxidation (PEO) films with uniform maze-like structures were obtained by anodizing Al in an ammonium tetraborate solution. High-purity Al plates were galvanostatically anodized in 0.3–2.4 M ammonium tetraborate solutions at 303–343 K and 10–100 Am−2 . A PEO film consisting of an outer porous layer consisting of amorphous alumina and crystalline alumina with α-and γ-phases and an inner amorphous barrier alumina layer was obtained on the Al surface. An extremely uneven PEO film with various pore sizes and many cracks was formed in a 0.3 M ammonium tetraborate solution, whereas a relatively uniform porous PEO film with similar pore sizes was obtained in 0.9–2.4 M solutions. This difference in the PEO film morphology was due to the plasma generation behavior while anodizing. The lightness of the PEO film increased with increasing anodizing time and PEO film thickness; thus, a bright white PEO film measuring 87.5 in lightness (L*) was formed on the Al surface. The water wettability of the PEO film exhibited weak hydrophilicity. Moreover, a superhydrophobic PEO film with a contact angle of 154° was easily fabricated by self-assembled monolayer modification. Similar bright white PEO coatings were successfully fabricated on various industrial alloys. [ABSTRACT FROM AUTHOR]

Hydrophobic interactions have been studied before in detail based on hydrophobic polymers, such as polystyrene (PS). Because fluorinated materials have relatively low surface energy, they often show both oleophobicity and hydrophobicity at the macroscopic level. However, it remains unknown how fluorination of hydrophobic polymer influences hydrophobicity at the microscopic level. We synthesized PS and fluorine-substituted PS (FPS) by employing the reversible addition-fragmentation chain transfer polymerization method. Contact angle measurements confirmed that FPS is more hydrophobic than PS at the macroscopic level due to the introduction of fluorine. However, single molecule force spectroscopy experiments showed that the forces required to unfold the PS and FPS nanoparticles in water are indistinguishable, indicating that the strength of the hydrophobic effect that drives the self-assembly of PS and FPS nanoparticles is the same at the microscopic level. The divergence of hydrophobic effect at the macroscopic and microscopic level may hint different underlying mechanisms: the hydrophobicity is dominated by the solvent hydration at the microscopic level and the surface-associated interaction at the macroscopic level. [ABSTRACT FROM AUTHOR]

A Zn-Al layered double hydroxide (LDH) conversion coating was investigated as a surface treatment for galvanized steel. Zn-Al LDH crystals were grown in situ on the galvanized steel surface in room temperature at different periods. Grazing Incidence Xray Diffraction verified the formation of Zn-Al LDH flakes on the surface. Scanning Electron Microscopy showed that Zn-Al LDH flakes were evenly distributed as a continuous coating on the surface of galvanized steel. Roughness and surface free energy of the coatings were evaluated by Atomic Force Microscopy and contact angle measurements. Corrosion propensity of the LDH coatings was analyzed utilizing Electrochemical Impedance Spectroscopy (EIS) and polarization. A 6 times increase in impedance at 0.01 Hz and 10 times decrease in corrosion current density was achieved for galvanized steel by LDH conversion coating in best practice. To assess the role of the LDH conversion coatings on adhesion strength and corrosion resistance of overlying organic coatings, epoxy coating was applied on LDH conversion coated surfaces and tested by pull-off, salt spray and EIS. Results signified 23 times increase in impedance at 0.01 Hz and 80% decrease in adhesion loss for organically coated galvanized steel after LDH treatment at optimal condition. [ABSTRACT FROM AUTHOR]

By altering some synthesis variables, the morphology and structural properties of anodic TiO2 nanotube arrays (TiO2NTs) can be tailored to a specific application. This study aims to investigate the effect of electrolyte-containing ions from human plasma and annealing temperature on structural, morphological, and mechanical parameters of TiO2NTs films, targeting its potential biomedical applications. Bio-inspired TiO2NTs were grown from Ticp and its Ti6Al4V alloy by potentiostatic anodization in the recently developed SBF-based electrolyte, maintained at 10 °C and 40 °C. The thermal investigation was performed by TGA/DSC and used to define the phase transition temperatures used for annealing (450 °C and 650 °C). Morphological and structural parameters were evaluated by FE-SEM, XRD, contact angle measurements, and nanoindentation. Results show that self-organized as-formed TiO2NTs were grown under all synthesis conditions with different wettability profiles for each substrate group. At 450 °C annealing temperature, the beginning of nanostructures collapse starts, becoming evident at 650 °C. The nanoindentation characterization reveals that both electrolyte and thermal annealing exhibited low effects on the hardness and Young’s modulus. The tailoring of specific properties by different synthesis conditions could allow the individualization of treatments and better performance in vivo. [ABSTRACT FROM AUTHOR]

Wurtzite GaP nanowires are interesting for the direct bandgap engineering and can be used as templates for further growth of hexagonal Si shells. Most wurtzite GaP nanowires have previously been obtained with Au catalysts. Here, we show that long (∼500 nm) wurtzite sections are formed in the top parts of self-catalyzed GaP nanowires grown by molecular beam epitaxy on Si(111) substrates in the droplet consumption stage, which is achieved by abruptly increasing the atomic V/III flux ratio from 2 to 3. We investigate the temperature dependence of the length of wurtzite sections and show that the longest sections are obtained at 610 °C. A supporting model explains the observed trends using a phase diagram of GaP nanowires, where the wurtzite phase is formed within a certain range of the droplet contact angles. The optimal growth temperature for growing wurtzite nanowires corresponds to the largest diffusion length of Ga adatoms, which helps to maintain the required contact angle for the longest time. [ABSTRACT FROM AUTHOR]

This work reported a facile route for fabricating super-hydrophobic concrete via sizing sand grains. It was found that mixing the sands with a size ranging from 150–180 μ m into cement enabled the formation of a lotus-like surface with a papillary structure at micro-scale. SEM showed that the size of bumper was about 3 μ m. When spraying a fluorocarbon solution onto this surface, the porous nature of the cement matrix showed the advantage of taking the fluorocarbon into the internal structure of the concrete via capillary force. As a result, the sub surface up to a depth of ∼1.5 mm were transformed into a thick superhydrophobic layer directly. The contact angle (CA) of water droplets could reach 157° on this surface, and which could remain more than 150° after abrasion 100 cycles under a weight of 300 g at 360 grit sandpaper. This thick hydrophobic layer significantly reduced the corrosion rate of the steel the concrete at the Cl ^- environment by 620 times. The measurement of British pendulum number and compression strength revealed that this superhydrophobic layer was beneficial for maintaining the friction coefficient of the concrete surface in wet condition without altering the mechanical integrity of the concrete.

This work presents the effect of drying temperature on the formation of poly(vinyl chloride) (PVC) honeycomb microstructures formed by the breath figure technique. Results revealed the self-assembly of honeycomb patterns with small cell diameter and thick cell walls dried at room temperature. An increase in cell diameter and a decrease in wall thickness were observed as drying temperature was increased up to 70 °C while no formation of patterns was noted at temperatures greater than or equal to 80 °C. The presence of honeycomb patterns consequently enhanced the static water contact angle of the PVC layer. Electrowetting experiments revealed more pronounced reduction in the water contact angle on honeycomb-structured PVC compared to a flat PVC layer at any given applied voltage. A proof-of-concept on the feasibility of the honeycomb structures to trap microparticles by electrically-driven droplet actuation was further demonstrated. Corresponding SEM images confirmed the entrapment of microparticles in the honeycomb cells and walls after the electrowetting experiment. These results offer new and facile strategies for tuning the morphological properties of polymeric honeycomb microstructures and its possible application in microparticle trapping and sensing.

To explore the wetting behavior of nanofluid under high voltage, a contact angle measurement system under electric field is designed and set up. The effects of mass concentration, the type of nanoparticles and the temperature of dielectric layer are considered. The experimental results manifest that the contact angle reduction rate of SiO2-water nanofluid is gradually increased with the increase of nanofluid concentrations from 0 to 0.05 wt%. While, it is decreased when the concentration is varied from 0.05 to 0.25 wt%. On the other hand, the contact angle reduction rate of Al2O3-water nanofluid is generally greater than SiO2-water nanofluid with the same volume concentration. In addition, the reduction rate of the contact angle of the SiO2-water nanofluid would be gradually increased with the increase of the surface temperature of the dielectric layer. Moreover, the experimental values are greatly deviated from the results calculated by Young–Lippmann equation and its modified form of nanofluid. Hence, the present study proposes a dimensionless surface tension correct factor to obtain the modified equation which is based on the Young–Lippmann equation. The influence of electric charge, electric field force, drag force and Brownian force on nanoparticles under high voltage are considered in the modified equation. The results show that the modified equation can predict the trend of the nanofluid contact angle under higher voltage. [ABSTRACT FROM AUTHOR]

Cobalt-silicon based carbon composites (Coâ€"Si/C) have established a noteworthy consideration in recent years as a replacement for conventional materials in the automotive and aerospace industries. To achieve the composite, a reactive melt infiltration process (RMI) is used, in which a melt impregnates a porous preform by capillary force. This method promises a high-volume fraction of reinforcement and can be steered in such a way to get the good “near-net” shaped components. A mathematical model is developed using reaction-formed Coâ€"Si alloy/C composite as a prototype system for this process. The wetting behavior and contact angle are discussed; surface tension and viscosity are calculated by Wang’s and Egry’s equations, respectively. Pore radii of 5 ÎĽm and 10 ÎĽm are set as a reference on highly oriented pyrolytic graphite. The graphs are plotted using the model, to study some aspects of the infiltration dynamics. This highlights the possible connections among the various processes. In this attempt, the Coâ€"Si (62.5 at.% silicon) alloy’s maximum infiltration at 5 ÎĽm and 10 ÎĽm radii are found as 0.05668 m at 125 s and 0.22674 m at 250 s, respectively. [ABSTRACT FROM AUTHOR]

A novel Ti/Sn-SbOx/PbO2-ODP electrode was constructed using a β-PbO2 layer modified with octadecyl phosphonic acid (ODP) through a co-electrodeposition method. Scanning electron microscopy with an energy dispersive spectrometer, X-ray diffraction and contact angle goniometry confirmed that ODP was successfully embedded into the β-PbO2 layer of Ti/Sn-SbOx/PbO2-ODP, increasing the water contact angle at the electrode surface from 75.9° to 133.9°. The Ti/Sn-SbOx/PbO2-ODP electrode exhibited excellent electrocatalytic oxidation of ciprofloxacin (CIP). The pseudo first-order rate constant for CIP removal was 3.92 h-1 at an electrolytic potential of 10 V, 2.6 times greater than that when using the unmodified electrode. Moreover, electrode stability was greatly improved after ODP modification. The Ti/Sn-SbOx/PbO2-ODP electrode had longer accelerated life (324 h) than the Ti/Sn-SbOx/PbO2 electrode (91 h). The enhanced electrocatalytic performance of Ti/Sn-SbOx/PbO2-ODP was attributed to improved utilization of hydroxyl radicals (•OH) resulting from higher oxygen evolution potential. Furthermore, the hydrophobic surface of Ti/Sn-SbOx/PbO2-ODP was beneficial for stronger adsorption of CIP, as evidenced by the initial surface concentration test. [ABSTRACT FROM AUTHOR]

In this paper, hydrophobic/superhydrophobic silicone rubber surfaces with disordered structures were prepared with a nanosecond laser. The fractal characteristic of the surfaces was also investigated. The results show that the fractal structures on the processed silicone rubber surface can roughly reflect the increasing trend of its hydrophobicity. More specifically, the air content in the liquid–solid contact area was found to be related to the surface superhydrophobicity. The solid fraction of superhydrophobic surfaces at close to 0.22 produced with different laser pulse widths can be used to identify whether such surfaces are in the superhydrophobic state after the laser treatment. In addition, the fractal parameters and gas/solid fraction could be used to predict the contact angles of surfaces in Wenzel and Cassie–Baxter states based on the fractal wetting equations. However, it is noted that with the increase of the laser fluence, the silicone rubber surfaces enter into a mixed state where the Wenzel and Cassie–Baxter states coexist. This paper provides a new method to characterize the wettability of the surfaces with the disordered microstructures. [ABSTRACT FROM AUTHOR]

Graphene-based materials play an essential role in a wide range of modern technologies due to their surface properties such as adsorption capacity and controllable wettability, which depend on the production methods. For practical applications, it is crucial to control the surface properties to achieve the desired wetting characteristics, which can be described with the contact angle (CA). Here, we experimentally investigate the wettability properties of the carbon nanowalls and show how to manage a wetting transition from superhydrophobic to superhydrophilic states. A CA of 170° was reached with direct plasma synthesis, while an angle smaller than 20° was achieved during the atmosphere plasma modification. Combining the formation of the surface groups due to the plasma treatment results and the macroscale wetting behavior in terms of the Cassie–Baxter model, we qualitatively explain how the observed wetting enhancement is induced by both controlled chemical and geometrical surface-heterogeneity. [ABSTRACT FROM AUTHOR]

Widespread concern has been attached to the frequent occurrence of pollution by oil slicks and water-soluble pollutants in recent years. The semiconductor photocatalysis is applied to sewage treatment owing to the advantages of energy-conserving and environmental protection. However, its application is limited by the defects of not solving oil slicks and the hard recyclability. In this paper, the high specific surface area and rod-shaped CdS were prepared using template and alkali-treated methods. Next, the alkylated SiO2 and alkali-treated CdS were deposited on pure fabric by physical deposition to prepare the multifunctional superhydrophobic fabric. The specific surface area and morphology of alkali-treated CdS were tested by BET specific surface area test and field emission scanning electron microscope. Besides, oil/water separation, water contact angle, and stability test experiments were performed to determine the superhydrophobic performance. Photocatalysis degradation efficiency and cycle degradation stability of multifunctional fabric were characterized by photocatalysis degradation Rh B experiment. Consequently, the alkali-treated CdS displays a high specific surface up to 343 m2 g−1. The multifunctional fabric presents excellent superhydrophobic performance with the water contact angle up to 155°. Meanwhile, the water contact angle of multifunctional fabric is always over 150° under various circumstances (acid-base corrosion, soaking time at 100 °C and frictional numbers), indicating that the multifunctional fabric has excellent superhydrophobic stability. Moreover, the fabric also exhibits outstanding photocatalysis performance (the degradation efficiency is 94% after 3 cycles). Our work provides a feasible method for addressing oil slicks on water surface and degrading water-soluble pollutants with extensive application prospects in water resource remediation. [ABSTRACT FROM AUTHOR]

Nanostructures are used for various chemical, biological, and even volatile organic compound (VOC) sensor applications, in which the inkjet printer provides an easy and convenient fabrication method. In particular, nanoparticles in injected droplets form various self-assembled nanostructures after evaporation such as flat films, rings, and domes, whose patterns are largely influenced by the flow fields within those droplets, temperature, humidity, and substrate wettability. In addition, the temperature at the liquid–gas interface of the droplets governs the local surface tension and evaporation flux, thereby determining the convection fluid flow and particle movement. In this study, we investigate four particle deposition patterns via numerical simulations. First, we reveal the formation of monolayered flat-films on a superhydrophilic substrate in the constant contact angle (CCA) mode during evaporation. Second, we confirm that particles in evaporated droplets usually form coffee-ring patterns on a hydrophilic substrate, which are mainly governed by capillary flows. Interestingly, we find that the coffee rings with low aspect ratios appear to be well-ordered in the constant contact radius mode, while those with high aspect ratios appear to be non-uniformly self-assembled in the CCA mode in an amorphous structure. Third, we prove that the Marangoni flow generated on a hydrophobic substrate accumulates particles at the center of the droplet, forming well-ordered dome-shaped patterns. Furthermore, we experimentally demonstrate four different particle deposition patterns to validate our simulation results and confirm that both sets of results are in reasonable agreement with each other. Hence, we believe that these theoretical model and simulation results can help to develop various nanostructure-based sensor applications by enhancing their performance. [ABSTRACT FROM AUTHOR]

Superhydrophobic surface on anodized AA5083 sample was obtained by an electrochemical process. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy analyses revealed the hierarchical structure of the coating and the presence of manganese stearate. These features were crucial for the coating superhydrophobicity, demonstrated by a measured contact angle of ~163° and its self-cleaning ability. Electrochemical characterization in an aqueous solution mimicking seawater proved an enhanced corrosion resistance due to the superhydrophobic coating with respect to anodized AA5083 sample that also lasted after 20 immersion days in Cl- containing electrolyte. [ABSTRACT FROM AUTHOR]

The fine nanopillars on the natural cicada wing, which exhibits outstanding superhydrophobicity and anti-reflectivity, are carefully observed and analyzed. Here, a promising strategy by combining anodic aluminum oxide template and hot embossing is proposed for rapidly and efficiently mimicking the orderly and densely arranged nanopillars on the cicada wing surface to polypropylene (PP) surfaces. By adjusting the compression pressure, the nanostructures on the PP replica surface gradually evolve from nanoprotrusion-like features to nanopillar-like features so that a gradient wetting behavior from hydrophilicity to hydrophobicity and further to superhydrophobicity appears on the PP replica surfaces. Specifically, the biomimetic PP replica surface exhibits a contact angle of 159 ± 3° and a rolling angle of 8 ± 3° at a compression pressure of 15 MPa. Moreover, the biomimetic PP replica surface can stabilize its superhydrophobic state under a 1.96 kPa external pressure during the dynamic droplet impact. Besides robust dynamic superhydrophobicity, the biomimetic PP replica surface also demonstrated excellent anti-reflectivity because of the gradually changed effective refractive index. Therefore, the biomimetic PP replica inherits both the superhydrophobicity and anti-reflectivity of the natural cicada wing, which makes the products can effectively reduce the external damage when applied to agricultural films, dustproof films, and packaging materials. [ABSTRACT FROM AUTHOR]

The novelty of present work is surveying deformation, split up and remained volume of Newtonian droplet impact with diameter d = 1.6, 2 and 2.4 mm and the droplet velocity in v = 1 and 2 m s−1 around the solid cylinders without flap, with simple and angle flap. Three-dimensional simulation was based on the volume of fluid method with dynamic contact angle of droplet and validated with the experimental results of a droplet impact and spread over the edge surface. Comparison split up volume of droplet between cylinder without flap, with simple and angle flap, the least percentage of split up volume of droplet (16%) was on solid cylinder with angle flap for droplet d = 1.6 mm and v = 1 m s−1. Also, the maximum remained volume of droplet (5.1781 × 10−9 m3) was on the solid cylinder with angle flap for droplet d = 2.4 mm and v = 1 m s−1. [ABSTRACT FROM AUTHOR]

The development of durable and high-performance absorbents for in situ oil–water separation is of critical importance for addressing severe water pollution in daily life as well as for solving accidental large-scale oil spillages. Herein, we demonstrate a simple and scalable approach to fabricate magnetic-responsive superhydrophobic melamine sponges by in situ deposition of PDA coatings and Fe3O4 nanoparticles, followed by surface silanization with low surface energy 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PTOS) layer. The prepared melamine sponge composite (PTOS-Fe3O4@PDA/MF) not only exhibits a very high water contact angle of 165 ± 1.5° and an excellent ability to uptake a variety of oils and organic solvents (e.g. up to 141.1 g/g for chloroform), but also shows robust durability and superior recyclability. The PTOS-Fe3O4@PDA/MF sponge can also efficiently separate oils (or organic solvents) and water, as demonstrated by different model systems including immiscible oil–water solution mixture and miscible water–oil (W/O) emulsion (stabilized by surfactants). Furthermore, the PTOS-Fe3O4@PDA/MF sponge is able to in situ recover organics from water using a peristaltic pump, which gives it significant advantages over other traditional batch processes for oil–water separation. We believe that the PTOS-Fe3O4@PDA/MF sponge provides a very promising material solution to address oil–water separation, especially for the large-scale problems that have been long-time challenges with conventional sorption methods. [ABSTRACT FROM AUTHOR]

Many factors are known to affect the vibration characteristics of sessile micro-droplets, such as surface tension, liquid densities, and contact angles. In this study, the vibration signals of the sessile micro-droplets under the conditions of different contact angles and viscosities were obtained using experimental processes. A theoretical model was designed based on the experimental phenomena in which the contact angles and contact lines were fixed. Then, similar to the vibrations of solid elastic film, it was assumed that the vibration waves of the sessile droplets existed within a certain thickness of the droplet surfaces, which provided a theoretical basis for the periodic correction coefficients. It was found that although the model was simple, it was in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Achieving a balanced strength-toughness in polymer composites is a challenge largely because of poor interfacial interaction between the fillers and matrix. Here, we report that terpolymer grafted multi-wall carbon nanotubes (Ter-CNT) imparted good dispersion of CNT in matrix and strong CNT-matrix interaction. With the addition of 2 vol% filler into polymethyl methacrylate (PMMA) matrix, the composite exhibited simultaneously a balanced strength-toughness property with flexural strength of 72.3 MPa, toughness of 10.1 MJ m−3, which increased by 40.1% and 578% compared with those of pure PMMA. In addition, the composite also shows a high static contact angle (110.3°), and thermal conductivity (0.50 Wm K−1), which endow the composite with good self-cleaning and thermal management capabilities. Thus, this preparation process shows guidance for the design of polymer composite with integrated high strength-toughness, thermal conductivity and good self-cleaning. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces demonstrate significant characteristics which make them suitable for a wide variety of applications. In this study, we propose a facile, one-step, and cost-effective anodizing scheme using aluminum nitrate/stearic acid mixture solution to create a superhydrophobic surface on an aluminum mesh. The surface outperforms the surface anodized by the widely used oxalic acid solution in terms of superhydrophobicity and water-surface friction behavior. The proposed surface reduced the friction by 11% on average respective to the surface prepared by oxalic acid. The durability of the introduced superhydrophobic surface has also been investigated. The proposed surface retained its high water contact angle and showed higher hydrophobicity relative to the surface anodized by oxalic acid after ten abrasion cycles. This method and surface may be used for numerous applications due to its ease of fabrication, low cost, and excellent performance in energy-loss reduction. [ABSTRACT FROM AUTHOR]

Droplet motion has been a long-standing interest in microfluidics as it is often limited by the high operating voltages, which hampers the development of consumer applications. Forces generated by liquid dielectrophoresis (L-DEP) can enhance surface wetting, without requiring chemical modification or surface texturing. This work presents a droplet actuating platform to control the wetting behaviour of water droplets using L-DEP. The exploitation of high electric fields at the droplet solid–liquid interface reduced the operating voltages. The operating voltage can be further reduced, to as low as 30 V, by introducing a lubricant layer to minimise the droplet contact angle hysteresis, thus requiring a smaller L-DEP bulk force. The outcomes of this study will provide a new pathway for developing energy-efficient and reliable droplet actuating platforms to clean a variety of surfaces. A particular interest will be the application of this system in the automobile sector, for instance, to clean headlamps, sensors, cameras, door mirrors, front side glass, and rear screen. [ABSTRACT FROM AUTHOR]

This paper aims at studying the influence mechanism of gas temperatures (300 K, 400 K, 500 K, and 600 K) on gas atomization by simulating the integral atomization process of the close-coupled nozzle in vacuum induction gas atomization (VIGA). The primary atomization is simulated by the volume of fluid (VOF) approach, and the second atomization is studied by the discrete phase model (DPM) combined with the instability breakage model. The results show that, at an increased gas temperature, the influences of gas–liquid contact angle and gas temperature in the recirculation zone on the primary atomization are virtually negligible. However, increasing the gas temperature will increase the gas–liquid relative velocity near the recirculation zone and decrease the melt film thickness, which are the main reasons for the reduced mass median diameter (MMD, d50) of primary atomized droplets. During the secondary atomization, increasing the gas temperature from 300 K to 600 K results in an increase in the droplet dispersion angle, which is beneficial to the formation of spherical metal powder. In addition, increasing the gas temperature, the positive effect of gas–liquid relative velocity increase on droplets refinement overweighs the negative influence of the GMR decrease, resulting in the reduced MMD and diameter distribution interval. From the analysis of the atomization mechanism, the increase in atomization efficiency caused by increasing the temperature of the atomizing gas, including primary atomization and secondary atomization, is mainly due to the increase in the gas drag force difference between the inner and outer sides of the annular liquid film. [ABSTRACT FROM AUTHOR]

A recoverable self-cleaning surface is studied by coating the nanostructured core–shell microcapsules like a chestnut bur. The microcapsules encapsulate the hydrophobic agent so that when they are broken by mechanical damage, it is released and functions to recover the loss of the self-cleaning performance. The core–shell droplets encapsulating the hydrophobic agent are generated continuously by introducing immiscible fluids into a multi-coaxial microfluidic channel platform and cured by UV irradiation to be polymerized. The control of the size and shell thickness of the microcapsules, and the volume of the hydrophobic agent are examined. Also, the nanostructures on the surface of the microcapsules are obtained by the polyaniline process for additional increase in roughness. The critical breakage forces of the microcapsules are measured for increasing the shell thickness. Finally, the nanostructured microcapsule surface is fabricated on a glass substrate and the water contact angle is measured to determine the self-cleaning performance. Also, its recovery of the self-cleaning performance surface from the mechanical damage is demonstrated. The formation of the recoverable self-cleaning surface by coating enables to apply for a large scale and arbitrary curved surface. [ABSTRACT FROM AUTHOR]

Understanding the mechanism of coalescence-induced self-propelled jumping behavior provides distinct insights in designing and optimizing functional coatings with self-cleaning and anti-icing properties. However, to date self-propelled jumping phenomenon has only been observed and studied on superhydrophobic surfaces, other than those hydrophobic surfaces with weaker but fairish water-repellency, for instance, vulcanized silicon rubber (RTV) coatings. In this work, from the perspective of thermodynamic-based energy balance aspect, the reason that self-propelled jumping phenomenon does not happen on RTV coatings is studied. The apparent contact angles of droplets on RTV coatings can be less than the theoretical critical values therefore cannot promise energy surplus for the coalesced droplets onside. Besides, on RTV and superhydrophobic surfaces, the droplet-size dependent variation characteristics of the energy leftover from the coalescence process are opposite. For the droplets coalescing on RTV coatings, the magnitudes of energy dissipations are more sensitive to the increase in droplet size, compared to that of released surface energy. While for superhydrophobic coatings, the energy generated during the coalescence process can be more sensitive than the dissipations to the change in droplet size. [ABSTRACT FROM AUTHOR]

This work describes the effects of catalyst layers (CLs) consisting of hydrophobic PTFE on the performance and water management of PEM fuel cells. Catalyst inks with various PTFE contents were coated on Nafion membranes and characterized using contact angle measurements, SEX-EDX, and mercury porosimetry. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were conducted under varying operating conditions for the prepared materials. At dry conditions, CLs with 5 wt.% PTFE were advantageous for cell performance due to improved membrane hydration, whereas under humid conditions and high air flow rates CLs with 10 wt.% PTFE improved the performance in high current density region. Higher PTFE contents (≥20 wt.%) increased the mass transport resistance due to reduced porosity of the CLs structure. Operando neutron radiography was utilized to study the effects of hydrophobicity gradients within CLs and cathode microporous layer (MPLC) on liquid water distribution. More hydrophobic CLs increased the water content in adjacent layers and improved performance, especially at dry conditions. MPLC with higher PTFE contents increased the overall liquid water within the CLs and GDLs and escalated the water transfer to the anode side. Furthermore, the role of back-diffusion transport mechanism on water distribution was identified for the investigated cells. [ABSTRACT FROM AUTHOR]

The diffusion layer is a crucial part of most fuel cells and electrolyzers. We analytically solve a simplified set of visco-capillary equations for the gas and liquid saturation profiles inside such layers. Contrary to existing numerical simulations, this approach allows us to obtain general scaling relations. We derive simple explicit equations for the limiting current density associated with reactant starvation, flooding, and membrane dehydration, including the effect of fluid properties, contact angle, tortuosity, and the pore size distribution. This is the first explicit, extensive and thorough analytical modeling framework for the two-phase transport in an electrochemical cell that provides useful insights into the performance characteristics of the diffusion layer. A more even pore size distribution generally allows higher currents. Explicit expressions for the minimum pore size and maximum layer thickness show that modern diffusion layers are typically well-designed [ABSTRACT FROM AUTHOR]

Given that the ballscrew raceway profile directly affects the service characteristics and precision retention of ball screws, this paper proposes an optimized continuous measuring method for the ballscrew raceway profile, without the need to adjust the sensor for the measurement of each raceway. Based on a comparison with existing measuring methods and principles, an optical measuring system is constructed, in which installation errors in the LED sensor and the linear calibration system, together with the straightness of the mobile platform, are obtained and analyzed. More importantly, in this work, we propose a transformation algorithm for the helix angle as well as an arc-selecting principle. Compared to the measurment results and time consumption of the profilometer, the maximum error for the measured radius and contact angle of the system proposed in this paper is 1.5 μm and 35′, and the measuring efficiency is increased by 15.8%, 58.6%, and 67.5% for 1, 5, and 20 continuous raceways, respectively, indicating effective performance in terms of accuracy, repeatability, and efficiency. Moreover, the system is also capable of measuring the pitch diameter and lead error of the ballscrew, which is significant in regard to classifying the accuracy of the ballscrew raceway profile, and improving machining precision. [ABSTRACT FROM AUTHOR]

The capability of hexagonal boron nitride (h-BN) to adsorb gas atoms may stimulate various promising applications in environment remediation and energy storage, while the interactivity with gas molecules yet remains challenging due to its inherent chemical inertness. In this article, we report a feasible and effective route for the scalable synthesis of vertically aligned h-BN nanowalls assisted by reduced graphene oxide (rGO) without metallic catalysts. The average thickness of the fine h-BN nanowalls is few-atomic layers about 3.7 nm, that grow on the large substrate-like flakes transformed from the pristine rGO. The hierarchical h-BN nanowalls exhibit an enhanced gas adsorption performance, not only through physisorption owing to the synergistic combination of different porous geometries, but also through chemisorption via the open edge groups. Moreover, it demonstrates a significantly enhanced adsorption of CO2 over CH4 as compared to the h-BN nanosheets with similar sizes. Density functional theory calculations reveal that the –OH edge groups can effectively increase the adsorption capability towards CO2, accompanied by a shortened adsorption distance when the gas molecule is energetically stabilized. The wetting characteristics of h-BN nanowalls was further examined by contact angle goniometry. [ABSTRACT FROM AUTHOR]

In this work, a Lattice-Boltzmann-Method (LBM) model for simulating hysteresis in a proton exchange membrane fuel cell (PEMFC) electrode is presented. One of the main challenges hindering study of the cathode catalyst layer (CCL) in PEMFCs is the lack of understanding of two-phase transport and how it affects electrochemical performance. Previously, the microstructure details needed to build an accurate mesoscale model to examine such phenomena have eluded researchers; however, with advances in tomography and focused-ion-beam scanning-electron-microscopy (FIB-SEM), reconstruction of the complex porous media has become possible. Using LBM with these representations, the difficult problem of catalyst layer capillary hysteresis can be examined. In two-phase capillary hysteresis, both the equilibrium saturation position as well as its absolute value depends on the wetting history. Based on the models, it is ascertained that at lower capillary numbers, the liquid begins to undergo capillary fingering--only above a capillary pressure of 5 MPa, a regime change into stable displacement is observed. As capillary fingering does not lead to uniform removal of liquid, the prediction is that because high capillary pressures are needed to change to the regime of stable displacement, wicking is not as effective as the primary means of water removal. [ABSTRACT FROM AUTHOR]

In this study, a facile method was prepared to fabricate highly flexible, conductive and superhydrophobic polymer fabrics. Copper nanoparticles (CuNPs) were decorated on polypropylene fabrics using a simple spraying method and superhydrophobicity was obtained after vacuum drying for 4 h without any surface modifier. Accumulation of CuNPs constituted coral-like rough micro-nano structures, forming a stable Cassie model and endowing the surface with dense charge transport pathways, thus resulting in excellent superhydrophobicity (water contact angle ∼159°, sliding angle ∼2.3°) and conductivity (sheet resistance ∼0.92 Ω sq−1). The fabrics displayed superior waterproof and self-cleaning properties, as well as great sustainability in the water. Additionally, the superhydrophobicity and conductivity can be almost maintained after heat treatment, wear testing, water droplet impinging, weak alkali/acid treatment and repeated bending-kneading tests. These superhydrophobic and conductive fabrics that are free from moisture and pollution can be a reliable candidate to solve the water-penetration issue in the rapid development of flexible electronics. [ABSTRACT FROM AUTHOR]

Recently, SnO2 is considered to be one of the most promising materials as electron transport layer in perovskite solar cells (PSCs). Low-temperature processed SnO2 films are crucial for SnO2-based PSCs and flexible devices. However, it is difficult to prepare stoichiometric SnO2 films by e-beam evaporation at low-temperature. Herein, SnO2 films are fabricated by oxygen plasma activated e-beam evaporation technique at room-temperature. Oxygen plasma shows strong oxidation activity, which is essential to adjust the stoichiometry of SnOx in the evaporation process. The SnO2 films exhibit uniformity (Rq = 3.05 nm), high transmittance (T > 90%), high hall mobility (μe = 10.8 cm2 V−1 s−1) and good hydrophilic (water contact angle =19°). This work will promote the application of SnO2 films in PSCs and flexible devices. [ABSTRACT FROM AUTHOR]

Using molecular dynamics simulations, we have revealed a novel wetting phenomenon with a droplet on composite structures formed by embedded water into (111) surface of β-cristobalite hydroxylated silica. This can be attributed to the formation of a composite structure composed of embedded water molecules and the surface hydroxyl (–OH) groups, which reduces the number of hydrogen bonds between the composite structure and the water droplet above the composite structure. Interestingly, a small uniform strain (±3%) applied to the crystal lattice of the hydroxylated silica surface can result in a notable change of the contact angles (>40°) on the surface. The finding provides new insights into the correlation between the molecular-scale interfacial water structures and the macroscopic wettability of the hydroxylated silica surface. [ABSTRACT FROM AUTHOR]

A graphene oxide (GO) membrane can be easily made by filtering a GO solution onto a supporting layer, and such a membrane is effective at adsorbing ions. But low flux and a high work pressure become an obstacle for its application in wastewater treatment. In this study, a positively charged mixture of carbon nanotubes and chitosan (CNTS) served as an interlayer to improve the GO membrane's flux. The three-layer membrane is known as MCG, while one without an interlayer is known as MG. For MCG and MG with the same GO load, the water flux of MCG reaches 2–8 times larger than that of MG. A better water permeability is consistently detected for MCG, with a contact angle descent speed of 3.3°/s, which is significantly faster than that of MG (0.5°/s). The ion rejections of MCG and MG are mostly attributed to GO adsorption, which stay at the same level. The flux varies with GO load, CNTS load and membrane dryness, while the ion rejection is correlated with the GO load. Optimized membrane fabrication conditions are suggested as being a CNTS load of 0.72 g m−2 and a GO load of 0.4 g m−2. A 'gap' mechanism is suggested to explain the interlayer effects. The rougher interlayer surface produces gaps between the GO and CNTS layers, which results in the faster water permeation and higher flux of MCG. These results demonstrate that it is possible to fabricate high flux GO membranes by adding a controlled-roughness interlayer. [ABSTRACT FROM AUTHOR]

Anti-reflection technology is a core technology in the field of optoelectronic devices that is used to increase efficiency by reducing reflectance. In particular, the bio-mimetic moth-eye pattern has the advantage of being independent of wavelength, polarization, and angle of incidence. In this study, we fabricated a 1.1 m wide meter-scale moth-eye film using roll-to-roll printing. A uniform moth-eye pattern with a height of 170 nm was formed, which reduced the average reflectance value by 3.2% and increased the average transmittance value by 3.1%, in a wide wavelength range of 400–700 nm. Additionally, the moth-eye film coated with a self-assembled monolayer (SAM) exhibited a contact angle of 140.3°, almost equal to the superhydrophobic angle of 150°. Furthermore, the contact angle, transmittance, and reflectance of the SAM-coated moth-eye film were maintained after an environmental test, which was conducted for 168 h at 60 °C and 80% humidity. [ABSTRACT FROM AUTHOR]

In this paper, we describe a novel fabrication method of a microfluidic integrated surface plasmon resonance (SPR) gold chip based on a (3-mercaptopropyl) trimethoxy silane (MPTMS) self-assembled monolayer. This monolayer was formed at the surface of a microfluidic chip made of polydimethylsiloxane (PDMS). Its presence was confirmed by contact angle and Fourier transform infrared spectroscopy measurements on the modified PDMS surface. A basic, but nevertheless appropriate, 4-channel microfluidic system was made on PDMS and reported on a gold SPR sensor. Sealing tests were carried-out by injecting continuous flows of solutions under gradient pressure up to 1.8 bar. Bonding strength of chemical and corona binding were measured and compared. The test of the integrated microfluidic SPR sensor on an SPR bench validated its functionality and proved as well that no leakage is observed between the different microfluidic channels. [ABSTRACT FROM AUTHOR]