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[Display omitted] • Blade coating and selective UV/O 3 surface treatment are used for the fabrication. • Salvinia-inspired surfaces show enhanced ability for air plastron preservation. • Hydrophilic top surface constrains the movement of the air plastron. • Hydrophilic top surface decreases the negative critical pressure for detachment. The preservation of air plastron on a submerged microtextured surface under negative pressure has always been a challenge. In this study, the Salvinia-inspired surfaces (SIs) are fabricated and studied to enhance the preservation of air plastrons. The blade coating method and the selective UV/O3 surface treatment facilitated by an adaptive mask are applied for facile fabrication of the SIs with hydrophilic top but hydrophobic side and bottom. The air plastrons of both the SIs and regular hydrophobic surfaces (HBs) with singular and patterned cavities are experimentally visualized and theoretically deduced. The two-stage morphological behaviors of plastron expansion, together with quantitative geometric parameters, are compared between SIs and HBs under various negative pressures. The hydrophilicity effect on SIs effectively preserves the air plastron by reducing the critical negative pressure required for detachment by 90% compared to HBs. The ability of plastron preservation is proved on SIs with patterned cavities by hindering the coalescence of air plastrons. Our study benefits the cost-effective fabrication of Salvinia-inspired surfaces and provides a theory model to predict air plastron morphology and reveal its mechanism of enhanced air plastron preservation capability under negative pressure, which expands their underwater applications, such as migrating cavitation erosion. In the future, the capacity to retain air under high pressure requires further investigation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fabrication of LIPSS on stainless steel enhances the hydrophilicity of the surface due to the formation of an oxide layer induced by the laser. • Hydrophilic to hydrophobic transition on LIPSS is achieved due to the adsorption of ethanolic triethoxyoctylsilane promoted by the oxide layer. • LIPSS wettability has a significant effect on cavitation dynamics, where hydrophobic surfaces accelerate the collapse time of the main bubble. • The enhancement of surface hydrophobicity increases cavitation erosion, which is directly related to the collapse time of the rebound bubble. The modification of surface wettability of stainless steel is essential for many biological applications and industrial implementations. Having a hydrophobic or hydrophilic surface is ideal depending on its application. In this study, the wettability tuning of stainless steel was carried out by producing LIPSS at different laser peak energies. Results showed non-significant changes in the periodicity of the ripples, however hydrophilicity increased with greater laser energies. Raman spectroscopy and SED analysis demonstrated the presence of iron oxide peaks and increased oxygen concentration, demonstrating a chemical surface modification governed by oxidation. Transitions from hydrophilic to hydrophobic surfaces were accomplished by ethanolic triethoxyoctylsilane coated LIPSS. Hydrophobicity enhancement was achieved by the adsorption of organic species promoted by the oxide layer at the ripples. The dynamics of cavitation bubbles close to the coated LIPPS were analyzed. A reduction of the main bubble lifetime with hydrophobicity, whereas a delay of collapse time and deformation of the rebound bubble were found. This led to an experiment for erosion testing producing multiple cavitation events. An increment of surface damage area with increased hydrophobicity was observed. This was attributed to longer collapse times of the rebound bubble which led to stronger shockwaves at the samples surface. This work demonstrates a simple method to tune the surface wettability of stainless steel by laser oxidation, which is a crucial factor for applications related to cavitation phenomena. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polymer structure manipulation is possible through solvent adjustment in topcoats. • Surface modification is possible through the manipulation of polymer structure. • Differences in de-icing properties exist depending on polymer chain conformation. • Optimal topcoat composition increased ice-delay effects by about 1.7 times. Icing on the topcoat layer of structures or mobility systems can be a factor leading to functional failures or accidents. Material engineering approach to prevent icing involves creating hydrophobic surfaces. In this study, it was confirmed that the method of controlling the structure of polymers using solvents to adjust surface hydrophobicity and ice prevention effects is effective. Polyurethane (PU) topcoats are primarily used on the exterior of mobility devices; therefore, structure of PU was manipulated using xylene. Through the adjustment of the ratio between PU and xylene, changes in the curing enthalpy and crystal structure were observed, which led to alterations in tensile strength. Additionally, changes in surface energy and contact angle occurred depends on xylene content, and de-icing property of PU topcoat was enhanced by 66 % on the surface of the 20 vol% xylene PU topcoat, compared to the pure PU topcoat. It was confirmed that the basic method of manipulating the polymer structure through solvent amount in topcoats could be utilized as a technique in hydrophobic surface research, such as ice prevention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stearic-acid zinc oxide coatings on biodegradable WE43 alloy. • Hydrophobic surfaces due to surface chemistry and topography. • Binding of hydroxyl groups with carbonyl groups rendering a chemically and mechanically stable surface. • Excellent degradation resistance with no Mg(OH)2 formation along with biocompatibility. Biodegradable Mg alloys are one of the most promising materials for implant applications, for which the widespread use is hampered by rapid degradation in physiological environment. The present study explores the development of a novel zinc-oxide (ZnO) loaded stearic acid (SA) coating on medical grade WE43 alloy using a facile, and environment-friendly technique for promising biomaterial surface applications. Morphology and chemical analyses reveal the development of a layered coating surface with uniformly dispersed ZnO nanoparticles in SA matrix. The developed coating exhibits hydrophobic performance (contact angle of 135°) along with the retainment of hydrophobicity under varying chemical (acidic pH of 1 and basic pH of 13) and mechanical (post scratch testing and peel-off studies) conditions. The observed surface water repellency facilitates self-cleaning performance pointing towards its efficacy against potential biofilm formation. The developed coating demonstrates superior resistance against surface degradation during immersion studies in phosphate buffer saline solution (pH = 7.4) and better cell viability with MG-63 (human osteosarcoma) cell line. The approach presented here sets a platform for the development of efficient coatings on biodegradable WE43 alloys surfaces for potential biomaterial technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Non-selective hydrophobic aggregation of particles worsened flotation index of ilmenite ore. • WG tended to adsorb onto titanaugite surfaces than ilmenite through physical adsorption. • Selective adsorption of WG only prevented the collector adsorption on titanaugite surfaces. • WG weakened non-selective aggregation of particles by diminishing hydrophobic attraction. • WG had the superior selective dispersion and inhibition in ilmenite flotation. Fine titanaugite readily adhered onto ilmenite surfaces in hydrophobic systems, resulting in a minor difference in floatability. This study utilized sodium silicate (WG) to address these issues. Flotation experiments showed that the serious non-selective hydrophobic aggregation of particles resulted in a low sorting index of a 44.81% TiO 2 grade and a 16.02% TiO 2 recovery when using conventional dispersants in flotation separation of actual ore. However, after utilizing WG, the index of flotation concentrate raised to a 46.50% TiO 2 grade and a 19.84% TiO 2 recovery. Turbidity analysis proved that WG had the strongest destructive impact on the non-selective hydrophobic aggregation between fine titanaugite and ilmenite particles compared to other dispersants. FTIR and XPS analyses verified that WG was inclined to adsorb onto titanaugite surfaces than ilmenite surfaces via physical adsorption. Zeta analysis proved that the selective adsorption of WG prevented the collector adsorption on titanaugite surfaces, while it had little effect on ilmenite surfaces. After adding WG, these changes in reagent adsorptions caused the increase of floatability difference of ilmenite and titanaugite and weakened the heterogeneous hydrophobic aggregation between particles by diminishing hydrophobic attraction. Taken together, WG has superior selective dispersion and inhibition in ilmenite flotation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface wetting behavior of ITO BRs was controlled using FOTS and UVO treatment. • Repeated FOTS and UVO treatments enabled reversible switching wetting and dewetting of liquid droplet. • Selective patterning of surface energy was achieved by masking the FOTS-treated regions from UV light. • Nanoscale wetting behavior was studied by depositing Ag NPs on ITO BRs. • Ag NPs on superhydrophobic ITO BRs exhibited strong LSPR, resulting in enhanced light absorption and scattering. Reversible control of hydrophobic and hydrophilic surfaces has gained attention due to their potential applications in microfluidic devices, membranes for electrochemical cells, and sensors. While external stimuli such as temperature and electric field can regulate surface properties, they cannot be selectively applied to specific regions, which limits the patterning of areas with different surface energies. Here, we present a simple and reversible method for converting hydrophobic and hydrophilic properties through surface treatments involving nonpolar (−CF x) or polar groups (–OH) on indium tin oxide branched nanowires (ITO BRs). The formation of nonpolar groups results in superhydrophobic surface. Subsequent ultraviolet ozone treatment, using a shadow mask, induces the exposed area to transition into a superhydrophilic state, while the unexposed area retains superhydrophobicity. This demonstrates the potential for selective-area surface energy patterning. Furthermore, we investigate the wetting behavior of nanoscale Ag nanoparticles (NPs) on surface-modified ITO BRs. It is observed that size and shape of Ag NPs depend on the surface energy of ITO BRs. Consequently, controlling the surface energy leads to the formation of unique geometric structure of Ag NPs, enhancing plasmonic light absorption and scattering at specific resonant wavelengths. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solvent choice changes the wettability of polybutadiene on ammonium perchlorate. • Carbonaceous deposits on ammonium perchlorate surfaces decrease hydrophilicity. • Amine-based bonding agents improve wettability of ammonium perchlorate. • Higher vapor pressure, non-polar solvents have minimal influence on surface wettability. Solid propellants are commonly used for propulsion systems due to their high volumetric thrust and reliability. Powder bed, binder jetting manufactured propellants will enable unique geometries to be made that are necessary for designers to achieve high thrust levels. However, changes to the particulate wettability from the solvent-based manufacturing technique must be understood such that propellants with adequate mechanical properties are achieved. In this work, the wettability of ammonium perchlorate (AP) crystal surfaces is quantified with solvent and air plasma treatments. Removal of adventitious carbon from AP surface decreases the polybutadiene contact angle from 34 ± 1° to 15 ± 4°. The presence of hydrocarbons from non-polar solvents used in this study with lower vapor pressure was observed to have a similar effect as the adventitious carbon whereas higher vapor pressure solvents have minimal influence on the final wettability of AP surfaces. Polar solvents were determined to alter the surface topology by creating a more hydrophobic surface when compared to the plasma treated samples. An increase in concentration of amine surface groups overcomes the decrease in wettability from carbonaceous residue and surface morphology. The extension and implications of these findings to powder bed, binder jetting manufacturing for propellants is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tailored hydrophobic SiO 2 /SiC membranes with simultaneous regulation of membrane surface wettability and pore structure. • The membrane maintains excellent pure water performance and thermal stability (≥400 °C). • A micron-sized monodisperse diesel emulsion can be obtained at emulsification flux of 1910 L·m−2·h−1. The combustion efficiency of diesel can be significantly improved in the form of emulsion, contributing to the reduced emission of nitrogen oxides. It is thus worthwhile to develop an energy-efficient way to prepare stable diesel emulsions with uniform droplet size. Ceramic membranes with hydrophobic surface are highly desirable for high-efficient membrane emulsification process. We proposed a novel and straightforward approach of immersing silicon carbide (SiC) membrane into hydrophobic silica solutions obtained by co-hydrolysis to tailoring hydrophobic SiO 2 /SiC membranes. The effects of methyltriethoxysilane addition and aging days on the hydrophobicity of these silica particles were systematically investigated. Then, the deposition of silica particles on the SiC substrates was further controlled by regulating the dipping duration and dipping times. The membranes (M2-SiO 2 /SiC) prepared with 240 s and dipping 4 times showed an increased contact angle (136°), mean pore size of 0.4 μm, open porosity of 30 %, and pure water permeance of ∼ 1500 L·m−2·h−1·bar−1. Moreover, the modified membranes were demonstrated to be mechanically stable. Furthermore, monodisperse diesel emulsions with an average droplet size of 2.1 μm and droplet size distribution of 0.61 can be generated by using the optimized M2-SiO 2 /SiC membranes at high emulsifying flux (1910 L·m−2·h−1). This work proposed an efficient strategy to simultaneously optimize the surface wettability and pore structure of ceramic membranes, satisfactorily for membrane emulsification applications with high efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanism of xanthate adsorption on hydrated ZnS is understood by QCM-D and DFTB+. • Adsorption of water is more favorable than EX/BX on unactivated ZnS. • Existence of water's lone pair electrons increases hydrophobicity of activated ZnS. • Interaction of EX/BX with hydrated, activated ZnS surface is chemisorption. • Higher reactivity of Cu+ d orbitals & orbital symmetry matching led to the results. The mechanism of surface hydration and xanthate adsorption in the flotation of unactivated/Cu-activated sphalerite is still controversial. Therefore, a study combining in-situ measurement and quantum simulation is employed to investigate the interaction mechanism of ethyl xanthate (EX) and butyl xanthate (BX) on the fully hydrated, unactivated/Cu-activated sphalerite surfaces at solid–liquid interfaces. Density functional based on tight-binding (DFTB+) and molecular dynamics (MD) results suggest that the Cu-activated surface is hydrophobic with the first layer of water being distributed more disorderly on it. This is due to the difficulty of the lone pair electrons of water to interact with Cu. On the unactivated surface, water adsorption is more favorable than xanthates, hence, water molecules are physically adsorbed on it. Whereas the interaction of EX/BX with the hydrated, activated surface is chemisorption. The higher reactivity of Cu+ d orbitals to form π-backbonds with xanthate and the orbital symmetry matching of the Cu d yz orbitals and xanthate p z orbitals contribute to these results. Microcalorimetric results also demonstrate that copper activation enhances the exothermic heat and reaction rate, facilitating the interaction of EX/BX with sphalerite. These are consistent with the flotation and quartz crystal microbalance with dissipation (QCM-D) results. [ABSTRACT FROM AUTHOR]

[Display omitted] • High purity Co thin film was formed by area-selective ALD with ODTS SAM. • NS surface is hydrophobic while GS is hydrophilic during Co AS-ALD using ODTS SAM. • Selective deposition of PEALD Co AS-ALD was achieved at temperature as low as 300 °C. As the semiconductor industry advances, manufacturing technologies encounter challenges in achieving precise alignment and thickness control with smaller and more intricate 3D structures. Addressing this, Area-selective atomic layer deposition (AS-ALD) emerges as a promising "bottom-up" approach, offering an alternative to current nano-patterning techniques. To achieve AS-ALD, self-assembled monolayers (SAMs) are employed as inhibitor agents. In this study, we employed plasma-enhanced atomic layer deposition (PEALD) to promote self-limiting surface reactions and enable low-temperature processing, thereby facilitating the implementation of high purity cobalt (Co) film through AS-ALD using octadecyltrichlorosilane (ODTS) SAM as an inhibitor. The selective deposition is achieved by employing SAMs as an inhibitor, belonging to the deactivation process, a common method for realizing a bottom-up approach. SAMs can form a thin organic film on a solid surface, allowing for surface modifications to become hydrophobic or hydrophilic. Through the selective deposition of Co in the PEALD low-temperature process (300 °C), we successfully addressed the degradation issue of ODTS SAM and verified the successful achievement of a high-purity selectively deposited 13.4 nm Co film. Our findings highlight the potential of selective Co deposition for realizing complex 3D structures and narrow interconnection layers. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuAl 2 O 4 modified by various saturated fatty acids changes from hydrophilicity to hydrophobicity. • CuAl 2 O 4 hydrophobization favors formation of more defective spinels and smaller Cu nanoparticles. • Synergism of hydrophobic surface and Cu with smaller crystallite size suppresses CO 2 formation. The intricate structure and surface properties of metal oxide catalysts pose a challenge for implementing hydrophobic surface treatment. Herein, the surface of CuAl 2 O 4 catalysts is modified by means of grafting and bridging different saturated fatty acid molecules, including lauric acid, palmitic acid and stearic acid. Consequently, the modification leads to an enhancement in the hydrophobicity of the catalyst, as evidenced by an increase in the static water contact angle from 15.26° to 150.74°. The hydrophobization of CuAl 2 O 4 catalysts, in turn, influences the decomposition and reduction capacity of CuAl 2 O 4 , thus favoring the formation of a more stable defective spinel structure and improving the dispersion of Cu particles, thereby restraining aggregation. Notably, the activity results indicate that the hydrophobically modified CuAl 2 O 4 exhibits higher CO conversion and selectivity of dimethyl ether, while effectively suppressing the water–gas shift reaction and reducing CO 2 selectivity. This observation points to the significance of the catalyst surface hydrophobicity in enhancing catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-stable CsPbBr 3 NCs-acrylate films was synthesized via a triple passivation strategy. • Poly@SiPNCs film exhibited high hydrophobicity (141.5 ± 1.9°). • Poly@SiPNCs film exhibited improved stabilities to water and UV light. • This work will boost a large-scale preparation of stable NCs-based films as backlight display. To improve the stability of CsPbBr 3 nanocrystals (NCs), triple protection strategies were performed to obtain the ultra-stable films, including fluorinated hydrophobic film surface, polymer coating and silica encapsulation. CsPbBr 3 QDs@SiO 2 nanoparticles (SiPNCs) were prepared with well-dispersed NCs (8 nm) within acrylate-modified silica-shell. Polymer@SiPNCs (poly@SiPNCs) films were prepared by copolymerization of methyl methacrylate (MMA), 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate (DFHM) and SiPNCs under ultraviolet (UV) light. Compared to CsPbBr 3 NCs solution, SiPNCs solution had well maintained light absorption and emission wavelengths of ∼509 nm and ∼522 nm respectively. High SiPNCs content resulted in enhanced micro/nano structure and increased roughness on the surface of poly@SiPNCs film. With increasing SiPNCs content, water contact angles (WCAs) of poly@SiPNCs films reached 126 ± 2.4°, 137.3 ± 1.3° and 141.5 ± 1.9° respectively. This fabricated poly@SiPNCs film exhibited much improved stabilities to water and UV light, even after 90 days of water immersion and 120 h of UV irradiation. White light-emitting-diode (LED) device emitted bright pure white light. This work will boost a large-scale preparation of stable QDs films as backlight display. [ABSTRACT FROM AUTHOR]

[Display omitted] • Successful synthesis of hydrophobic CuCl/LaA modified by butyltrichlorosilane (BTS). • The modification with La and BTS improves the stability of Cu+ significantly. • CO uptake by CuCl/LaA-BTS was much higher than pristine zeolite 5A at high humidity. • The regeneration performance of CuCl/LaA-BTS is satisfactory. Cuprous ion modified molecular sieves have been considered as promising CO adsorbents in gas separation or purification industry. However, it persists as a significant challenge to overcome the unfavorable effect of water vapor in the work environment on gas adsorption and separation. Herein, we propose a synthetic strategy using rare earth element La as an additive to form La O La coordination bonds followed by surface silanization treatment to construct a hydrophobic Si O Si barrier to significantly improve the stability of Cu+ under humid atmosphere. By successively introducing La3+ and Cu+ into zeolite 5A, CuCl/LaA adsorbents were prepared via ion exchange and solid dispersion methods. And then by silanization modification using toluene as solvent and butyltrichlorosilane (BTS) as hydrophobic agent, hydrophobic CuCl/LaA-BTS adsorbents were prepared. Dynamic adsorption investigation demonstrated that the as-prepared CuCl/LaA-BTS adsorbents possessed hydrophobic surface and consequently the adsorption capacity of CO was enhanced significantly under humid atmosphere. The CO adsorption breakthrough capacity over CuCl/LaA-BTS attained 0.34 mg/g, which was 5.7 times higher than that of zeolite 5A at 40 °C, atmospheric pressure and a relative humidity of RH = 55 %. Moreover, the CO adsorption capacity of CuCl/LaA-BTS retained 0.31 mg/g after four cycle regenerations. This work provides an effective and novel route for synthesizing highly stable cuprous ion modified zeolite adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coating stearic acid on Cu/CeO 2 improves its hydrophobicity with unchanged structure. • Stearic acid molecules are stably adsorbed with catalysts by bridging bidentate mode. • Water inhibition is greatly weakened by hydrophobic surface to improve acetone yield. Hydrophobizing the surface of catalysts is essential in many catalytic reactions confined by water, but it can be quite challenging for metal oxide catalysts because of their intricate structure and surface properties. Herein, a series of hydrophobic copper doped ceria-based catalysts was synthesized by introducing stearic acid over the surface of catalysts for the ketonization of acetic acid co-feeding with different concentration of water. Detailed investigations reveal that the stearic acid functionalization process obviously improves the hydrophobicity of Cu/CeO 2 without greatly changing their structures. Due to the excellent hydrophobicity to inhibit water in the reaction system, ketonization activities of acetic acid were greatly improved over the hydrophobic Cu/CeO 2 catalysts co-feeding with 10–65 mol.% water. Specifically, the acetic acid conversion and acetone yield reached 94 % and 87 % co-feeding with 47 % mol.% water at 330 °C over Cu/CeO 2 -2, respectively, outperforming stearic acid-free catalyst under the same conditions. Besides, the hydrophobic Cu/CeO 2 catalyst was with good durability up to 10 h on stream. The promotion of catalytic activities gives more details to help future research into the design and development of catalysts for future industrial applications of ketonization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Contact time dependence of adhesion force is closely related to surface hydrophilicity and relative humidity (RH). • The dependent behavior is logarithmically increasing with dwell time. • On hydrophilic surfaces, the force is dependent only at some RHs. • On most partially hydrophobic surfaces, the dependent behaviors are observed under all levels of RH. • The force on hydrophobic surfaces is independent under all levels of RH. Contact time dependence of adhesion force remains insufficiently comprehended and demands further clarification. Adhesion forces between cantilevers and various substrates were measured with atomic force microscopy to study the dependence at low, moderate, and high relative humidities (RH). Results indicate a strong correlation between the dependence and surface hydrophilicity. In some situations, the adhesion force exhibits a dependence on contact time: it experiences a rapid increase, followed by a gradual rise and eventual saturation with a saturation time of 20 ∼ 200 s. On hydrophilic surfaces, the force is dependent only at some RHs. On most partially hydrophobic surfaces, the dependent behaviors are observed under all levels of RH. However, the force on hydrophobic surfaces is independent under all levels of RH. With the dominant capillary force, the dependent behavior was attributed to the slow flow of thin films caused by the high viscosity of interfacial water. The high viscosity at low and moderate RHs was due to its configuration and film thickness, while that at high RH was due to contaminants and the formation of silica sols and gels. The findings have the potential to enrich the comprehension of adhesion and provide remedies for stiction-related problems in miniature devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • The regular hierarchical micro-nano structures were constructed via one-step etching. • The prepared superhydrophobic surface possesses a CA of 173.3° and a SA below 1°. • The surface prepared within 1h boasts high chemical stability and water resistance. Nowadays, achieving highly effective superhydrophobic surfaces on chemically active magnesium alloys via a straightforward and efficient etching method remains a formidable task. In this study, we have successfully fabricated regular mulriple hierarchical micro-nano structures on AZ91D substrates through a one-step etching process. The resultant nano-chrysanthemums exhibit remarkable biomimicry wherein the extended nanostructures and the protrusions on them further enhance the air–liquid interface contact area. Subsequent to the modification, the contact and sliding angles of the samples achieved exceptional performance surpassing that of previous etching techniques. Furthermore, this low adhesion surface demonstrates commendable chemical stability even when exposed to air, chemically aggressive solutions (including strong acids and bases), and cyclic icing/melting treatments. Moreover, this versatile superhydrophobic surface exhibits exceptional resistance to various forms of contamination. The method employed to generate such advantageous superhydrophobic surfaces necessitates minimal equipment complexity and boasts substantial advantages in terms of affordability and efficiency. These characteristics not only confer promising prospects for widespread application but also render it suitable for large-scale industrial production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molecular dynamics and free energy simulations revealed the hindering role of mineral surface hydration structure; • Hydrophobic coating of both the nanoparticles and the iron oxide surfaces is essential for selective adhesion; • Tuning the degree of surface coverage by oleate can lead to better nanoparticle-surface interactions; • Magnetic separation experiments of iron ore ultrafines validated the molecular-level analyses meeting experiment–theory nexus. Magnetic nanoparticles have diverse scientific and technological applications, as their properties can be tuned accordingly. An example is the selective magnetic coating technique for the selective adsorption of these colloidal particles on the surface of iron minerals to improve recovery of fines by magnetic separation. Thus, fundamental physicochemical knowledge of such systems is of paramount importance. Herein, we investigate the adsorption of magnetite nanoparticles on mineral surfaces and the impact of hydrophobic coating on the adsorption process and magnetic separation. We present structural and thermodynamic characterizations from molecular dynamics and free energy simulations to rationalize the differences in association process in both native and coated particle conditions. We demonstrate that hydrophobic coating of both nanoparticle and target iron oxide surfaces is essential for selective adhesion, revealed by ΔG. Also, tuning the degree of surface coverage by oleate leads to better interactions then simply establishing a monolayer coating, because of interdigitation of adsorption layers allowing higher contact area, shorter interparticle distance and less oleate consumption. Magnetic separation experiments of ultrafine iron ore particles under different oleate and colloidal magnetite concentrations validated the molecular level analyses, thus achieving successful experiment–theory nexus based on a sound theoretical background explored beforehand by computational simulations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of substrate-independent coatings with controllable surface chemistry. • HMDSO plasma polymerization on PCL-PLGA nanofibers without fiber damage. • APTES silanization of HMDSO-based coatings makes primary amine containing surfaces. • Improvement in cell-material interactions by APTES silanized coatings on nanofibers. Surface modification of hydrophobic nanofibers (NFs) to introduce cell-interactive chemical functionalities remains a challenge in biomedical applications. This study presents a novel three-step plasma-based method for synthesizing coatings with improved chemical selectivity compared to conventional plasma polymers. The process involved hexamethyldisiloxane (HMDSO) plasma polymerization followed by helium plasma activation, both performed in a medium-pressure dielectric barrier discharge. Scanning electron microscopy analysis demonstrated that the plasma-based steps did not cause damage to the NFs. X-ray photoelectron spectroscopy (XPS) and water contact angle measurements revealed the formation of a hydrophilic silanol-rich layer after HMDSO plasma polymerization and helium plasma activation. In the third step, (3-aminopropyl)triethoxysilane (APTES) was grafted onto the plasma polymer to introduce primary amine groups onto the surface, as confirmed by XPS. Although the APTES-based layer exhibited partial removal when exposed to aqueous environments, a stable aminated layer remained on the NF surface, which significantly enhanced Schwann cell responses compared to untreated and HMDSO-based coated NFs. This enhancement was confirmed through fluorescent imaging using live-dead staining, immunostaining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. These coatings with a high selectivity in their chemical functionality (amines, or other functionalities via silanization agent selection), offer a promising surface functionalization approach for tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the synergistic effect of two corrosion control strategies: application of an inhibitor and enhancing the surface superhydrophobicity, for protection of electrodeposited nickel in saline solutions. For this purpose, 4-Mercaptopyridine (C 5 H 5 NS) was added to the synthetic sea water solution and its corrosion inhibition efficiency was evaluated on electrodeposited smooth bright nickel layer and nickel films with hierarchical micro/nano structure. Stearic acid was used to tune the wetting properties of nickel films, from hydrophilic to superhydrophobic. Contact angle measurement, scanning electron microscopy, and Fourier-transform infrared spectroscopy were utilized in the characterization of deposited nickel layers. Potentiodynamic polarization and electrochemical impedance spectroscopy were employed to assess the corrosion inhibition performance of inhibitor on different nickel films. Our results indicate that simultaneous increase in the surface hydrophobicity and adsorption of corrosion inhibitor strategies does not yield a better corrosion resistance and that the most effective corrosion inhibition can be obtained on the bright smooth sample after a prolonged immersion in the corrosive solution. Furthermore, we show that the contact angle alone cannot be used to indicate the corrosion inhibition capability of an inhibitor. Unlabelled Image • Nickel films were electrodeposited on copper substrate • Stearic acid was used to provide superhydrophobicity • Corrosion inhibitor (4-Mercaptopyridine) was applied on electrodeposited surface • Synergistic effect of corrosion inhibitor and nickel film structure was evaluated • No corrosion protection synergy was observed for inhibitor + superhydrophobicity [ABSTRACT FROM AUTHOR]

Modification of carbon based-nanomaterials has been proven to be efficient for improving the MFCs performance, since the anode material significantly impacts the biofilm formation and the electron transfer between the microorganism and the electron acceptor. Surface treatment or functionalization is frequently employed to enhance the chemical reactivity and modify the hydrophobic surface of carbon nanotubes (CNTs). This work aims to explore the modification of CNTs with nitrophenyl groups for the improvement of the performance of MFC through anode modifications. Two procedures, involving 4-nitroaniline or 4-nitrobenzenediazonium tetrafluoroborate, were used for the chemical modification of CNTs. The X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and cyclic voltammetry were used for the characterizations of nitrophenyl modified CNTs. The maximum power density was obtained when 4-nitrobenzenediazonium tetrafluoroborate was used for the modification of the surface of CNTs. The introducing of nitrogen functionality on the anode surface and the control of the nitrogen content provide considerable encouragements for enhancing the MFCs performance through anode modifications. • CNTs surface was modified with nitrophenyl group via diazonium chemistry. • Nitrophenyl modified CNTs was used for the improvement of MFC performances. • Increase of nitrophenyl functionality on surface increased the power output of MFC. • Modification with tetrafluoroborate gives better coverage of nitrophenyl on surface. [ABSTRACT FROM AUTHOR]

In order to unravel the oxidation mechanism(s) of chalcopyrite (CuFeS 2) surfaces, the surface anisotropy of CuFeS 2 was investigated under both dry and aqueous atmospheres through a fundamental density functional theory (DFT) study. Results showed that the CuFeS 2 (112) surface was the preferred cleavage surface, rather than the commonly-assumed (001) surface. Iron oxides were formed when contacting with either molecular O 2 or dissociated O atoms, but sulfoxy species were only formed in the presence of dissociated O atoms, exposing Cu atoms on the S-terminated (001) and (112) surfaces. This indicates that strong oxidation conditions are beneficial to CuFeS 2 oxidation and the release of metals into solution. In addition, CuFeS 2 was preferentially oxidized by O 2 prior to the adsorption of H 2 O under an aqueous condition with both H 2 O and O 2. The H 2 O adsorbed on the O-oxidized surface further promoted CuFeS 2 oxidation, resulting in the formation of a hydrophilic surface, rather than the naturally hydrophobic surface. This study has unveiled, for the first time, the mechanisms of the oxidation of the most stable and reactive CuFeS 2 (112) and (001) surfaces under both dry and aqueous environments at an atomic level, with potential applications in CuFeS 2 flotation and leaching processes. Unlabelled Image • CuFeS 2 (112) surface was the preferential cleavage surface, rather than (001) surface. • S 2 2- and S n 2- species were formed on CuFeS 2 surfaces during relaxation process. • O 2 was adsorbed on CuFeS 2 surfaces prior to the adsorption of H 2 O. • M-terminated CuFeS 2 surfaces, rather than the S-terminated, can be easily oxidized by molecular O 2. • H 2 O was necessary to form dissociated O atoms on chalcopyrite surface. [ABSTRACT FROM AUTHOR]

Antiglare and antireflection materials take considerable research attention due to its important role in transparent optical materials for various purposes. In this study, we employed layer-by-layer coating materials consist of SiO 2 and TiZrO 2 deposited on etched-surface glass substrate using dual electron beam evaporator system. The surface morphology investigated by using scanning electron microscopy (SEM) exhibited the microstructure patterns of glass surface. The cross-sectional image of transmission electron microscopy (TEM) showed uniformly layer-by-layer coating materials with the thickness of ~20–80 nm. The Auger electron spectroscopy (AES) revealed the depth profiles of elemental composition of surface layer-by-layer coating, confirming the presence of elements of SiO 2 and TiZrO 2 layers. In addition, the layer-by-layer coated glass surface performed the hydrophobic properties with contact angle of 69°. The microstructure surface treatment and layer-by-layer coating have successfully decreased the reflectance (~3%) and increased the transmittance of the treated glass (~91%), opening the possibility for the applications of any optical devices. • Layer-by-layer deposition of SiO 2 and TiZrO 2 as antiglare and antireflection • Multilayer thin film coating with increased transmittance • Microstructure patterns through surface etching with hydrophobic capability • Homogeneous coating materials through dual electron beam evaporator • Potential applications for PV panel, laser, optical lenses and display devices [ABSTRACT FROM AUTHOR]

In this study, water droplet behavior on hydrophobic and superhydrophobic surfaces with different morphologies and geometries has been investigated using molecular dynamics method. The contact angle and potential energy of water droplet on nanostructured surfaces has been evaluated as criteria of hydrophobicity. Results show that surface morphology, distance between columns, void fraction and the growth angle are the main parameters that significantly influence surface hydrophobicity. Wetting transition from Cassie-Baxter state to Wenzel state of simulated structures show that contact the angle decreases with increasing the distance between the columns. Superhydrophobic thin films with different shapes and dimensions, namely tetragonal helical sculptured, gecko feet and lotus leaves were designed and simulated. A contact angle of 155.7° for tetragonal helical sculptured structure is achieved. Interestingly, gecko feet and lotus leaves structures show oscillatory behavior of potential energy curves. It implies that these surfaces are more hydrophobic than other simulated films. Unlabelled Image • Hydrophobicity of conical, lotus leaves, gecko feet and tetragonal helical morphologies was investigated using MD simulation. • Contact angle and potential energy of water droplet were evaluated as criteria of hydrophobicity or super- hydrophobicity • In conical and columnar morphologies hydrophobicity is increased with height of both conical and columnar structures. • In agreement with experimental results, hydrophobicity of tilted nano-cones is increased by increasing deposition angle. • The 155.7° contact angle of the simulated helical tetragonal structure is in good agreement with experimental reports. • Oscillatory behavior in potential energy curves of lotus leaves and gecko feet structures reveal these are super-hydrophobic. [ABSTRACT FROM AUTHOR]

Condensation of water vapor on a surface plays an important role in thermal based water purification methods. Appropriate texturing of such surfaces facilitates dropwise condensation with better heat transfer coefficient and water collection. In this context, we explore texturing patterns via laser ablation to achieve lower aspect ratio (10 μm depth to 100 μm width) and via wire electric discharge machining process for higher aspect ratio (300 μm depth to 100 μm width). The transition from Cassie-Baxter to Wenzel is seen experimentally as well as through the simulations for lower aspect ratio, whereas the transition does not occur for higher aspect ratio. Simulations are also carried out for the sessile as well as pendant drop, which is more relevant to thermal based water purification. However, in the experiments the drop is always in the pendant mode. The condensing surface inclination plays a very significant role in the water collection. In order to have more water production underneath the copper plate, the optimum angle of inclination found is 35°. Unlabelled Image • Hydrophobic surface using physical texturing by laser and EDM micromachining • Simulations for transition from Cassie Baxter to Wenzel state • Water production using physically textured and plain surface in desalination system • Time required for first drop to slide off on textured and plain surface • Effect of inclination angle on drop sliding on textured and plain surface [ABSTRACT FROM AUTHOR]

In this study, we propose new polymeric coatings for metallic implants that impart biocompatibility and antibacterial features to such surfaces. The starting material, poly(cyclic carbonate)-polydimethylsiloxane, was prepared from carbon dioxide fixation and then sequentially reacted by aminolysis with an organoaminosilane, affording the formation of an urethanic polydimethylsiloxane-based material. Finally, a hybrid coating was obtained by performing a sol-gel process on the metallic surfaces, catalyzed by phosphotungstic acid. We provide evidence that due to the polydimethylsiloxane segments governing the surface termination, the hybrid coatings show a hydrophobic character. Furthermore, due the presence of phosphotungstic acid in the upper surface, the adhesion of Gram-positive and Gram-negative bacteria is suppressed in 4 h of contact with aqueous bacterial cultures. In addition, the coatings presented a >70% cytocompatibility besides a low cytotoxicity, making them interesting candidates as biocompatible materials and an alternative to avoiding the biofilm associated with bacterial infections. Unlabelled Image • Hybrid polyurethane coatings were fabricated in a sustainable way by carbon dioxide fixation • The hybrid coatings presented osteoblast and fibroblast cell compatibility and, bacteriostatic behaviour • Bacteriostatic behaviour were evidenced in the presence of hybrid polyurethane PDMS-based coatings • Phosphotungstic acid catalyses the sol-gel reaction and cooperates with the suppression of bacterial adhesion • PDMS segments provide hydrophobic surfaces by coating substrates with hybrid polyurethane PDMS-based [ABSTRACT FROM AUTHOR]

Controllable protein adsorption on solids is of great importance in many modern technological applications. The role of the water phase in mediating the protein-surface interactions, however, still remains poorly understood. Herein, we employ free energy calculations to systematically explore the mechanisms of the surface adsorption/bioresistance correlating with the interfacial water layers. The studied peptide shows strong binding affinity with the hydrophobic surface, as illustrated by a monotonic decrease in the free energy profile with no energy barriers. However, the surface bioresistance could be triggered in two distinct ways, by not only an enhancement of the surface-water interactions, but also increased interactions between the water and adsorbates. The enhanced surface-water interactions decrease the tendency of the surface dehydration and the subsequent adsorbate penetration into the surface-bound water layers, thus leading to the surface bioresistance. On the other hand, the enhanced water-adsorbate interactions could promote water stabilization of the adsorbate in the bulk solution, effectively preventing the peptide adsorption. Our results further elucidate that the increase in the peptide size favors its adsorption on the hydrophobic surface, but go against the adsorption on the hydrophilic surface. The mechanisms revealed here may facilitate the design of novel proteins/peptides, materials, and solvents for a controllable adsorption at a solid-water interface. • The effect of the interfacial features on peptide adsorption is reported. • The water phase act as the origin of the surface resistance to peptide adsorption. • Two distinct roles of the water phase in the surface bioresistance are identified. • As the molecule size increases, the effect of water phase becomes more pronounced. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces are composed of low surface energy materials and micro/nano structures; however, in real applications, it is challenging to achieve surfaces that simultaneously have strong mechanical, chemical, and adhesive properties. We have made an acetone solution of benzoxazine, epoxy and mesoporous SiO 2 to form a superhydrophobic surface using spray coating. These superhydrophobic surfaces maintained their superhydrophobicity after a more than 2.9 m abrasion test under 1.6 kPa, can endure the acid and alkali corrosion for more than 12 h, and can reach first level adhesion to a tin plate. The reason of the simultaneously improvement in mechanical strength, chemical robustness, and adhesive properties is the self-similar, organic-inorganic interpenetrating structure and rational choice of components of formulation. With multifaceted robustness and scalability, these coatings should find potential use in harsh chemical engineering as well as in infrastructure and communication equipment. Unlabelled Image • Mechanical robustness superhydrophobic surface with excellent adhesive property was made. • Benzoxazine/epoxy/mesoporous SiO 2 is first reported to be used in superhydrophobic surface making. • Inorganic-organic interpenetrating structure is benefited for making a robustness superhydrophobic surface. [ABSTRACT FROM AUTHOR]

A change in surface wettability due to autogenous chemical and structural transition of electropolymerized polyaniline film is presented. A gradual increase in water contact angle of >150 ° on electropolymerized PANI surface was observed over the period indicated superhydrophobic surface. While an increase in the content of quinoneimine structure was observed, the surface morphology showed the formation of a dendritic structure on the aged PANI surface. Water contact angle measurement using different liquids showed the surface energy of PANI has decreased >70% after 30 days of exposure in the ambient environment. The findings are explained based on the mechanism of self-assembled micro-nano-cluster formation over PANI surface during continuous exposure. Unlabelled Image • Autonomous self-organization of hydrophobic asperities on PANI surface • Physical (hierarchical) and chemical structural transition • Surface transformation from superhydrophilicity to superhydrophobicity [ABSTRACT FROM AUTHOR]

Abstract Methacryloyl-terminated poly[methyl(3,3,3-trifluoropropyl)siloxane] (PMTFPS-MA) macro-monomers with controlled segment length were designed and synthesized by anionic ring-opening polymerization of 1,3,5-trimethyl-1,3,5-tri(3′,3′,3′-trifluoropropyl)cyclotrisiloxane (F 3). Then, a series of novel amphiphilic fluorosiloxane-containing graft copolymers were prepared using PMTFPS-MA, poly(ethylene glycol) methyl ether methacrylate (PEG-MA) and methyl methacrylate (MMA) as the co-monomers, and their surface properties and protein-resistant performance were investigated. It was found that the composition of amphiphilic graft copolymers would play an important role in the protein-resistant properties. When the copolymers contain 65.5 wt% PEO segments and 6.4 wt% PMTFPS segments, the coating surface exhibits strong protein-resistant property and shows almost no protein adsorption on it. Based on the surface analysis of amphiphilic graft copolymer films both in dry and wet conditions, the protein-resistant property of amphiphilic copolymers can be owing to the transition from a hydrophobic surface to hydrophilic surface with highly efficient water-driven PEO surface migration. The PEO segments are utilized to prevent protein adsorption whereas the low surface energy PMTFPS segments are utilized to drive away the adsorbed proteins. Graphical abstract Unlabelled Image Highlights • Novel amphiphilic fluorosiloxane-containing graft copolymers were prepared. • Copolymer composition plays an important role in protein-resistant properties. • The copolymer coating can exhibit strongly protein-resistant property. • The protein-resistant property of coating was owing to the wettability transition. [ABSTRACT FROM AUTHOR]

Abstract The excellent electronic properties of single-layer graphene provide the fundamental basis for its use in advanced electronics applications. Graphene-based biosensors, however, are one of the exceptions among the applications that take advantage of the unique properties of this material, because high hydrophobicity of graphene hinders the controlled immobilization of biomolecular probes, particularly of antibodies for immunoassays. In contrast to methods that rely on aggressive chemical oxidation of graphene, we overcome this challenge by implementing an effective strategy that modifies single-layer graphene to render it hydrophilic and biocompatible without compromising the electronic structure. Graphene produced in-house by chemical vapor deposition (CVD) was modified with a heterobifunctional linker that attached to the surface via a pyrene group and presented a standard N-hydroxysuccinimide (NHS) ester ligand for covalent immobilization of biomolecules. The suitability of thus modified surface for biofunctionalization was then confirmed via real-time monitoring of the immobilization of an antibody by quartz crystal microbalance (QCM) measurements followed by the chemical characterization by x-ray photoelectron spectroscopy (XPS). Finally, as a proof-of-concept for biofunctionalization of graphene without compromising its electronic structure, a graphene immuno-field-effect transistor (immuno-FET) was fabricated, biofunctionalized, and tested for detection of Matrix Metalloproteinase 9 (MMP-9), a biomarker related to clinical diagnostics of ischemic stroke. Graphical abstract Unlabelled Image Highlights • Biofunctionalize graphene to exploit unique electronic properties in biosensing • Systematically characterize each functionalization step by complementary techniques • Heterobifunctional linker between hydrophobic graphene surface and antibodies • Blocking strategy to minimize nonspecific adsorption after biofunctionalization • Biofunctionalized graphene EGFET for proof-of-principle biorecognition measurements [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was to elucidate how ice adhesion to solid substrates is related to surface wettability, which, in turn, results from surface chemical composition and nanotopography. The study was carried out using microscopically smooth surfaces of epoxy and SU-8, a negative epoxy-based photoresist. Epoxy resins are known for their outstanding physicochemical properties. They are often used as surface coatings for outdoor devices and can face harsh environmental conditions, such as icing. SU-8 is extensively used in microfabrication of surface topographical structures. Some of these structures are designed to be superhydrophobic and, in some cases, icephobic. In the present study, we focused on the role of surface physicochemical modifications of these materials in controlling their wetting and icing properties. A homologous series of fluoroalkyl silanes (FAS), which contained 3, 8, 10, and 12 carbon atoms in a molecule, was used to make epoxy and SU-8 surfaces hydrophobic. The FAS deposition process was carried out from vapor phase at atmospheric pressure (AP-VPD). The modified substrates exhibited a significantly increased surface nanoroughness, as a result of etching in oxygen radio frequency (RF) plasma and subsequent silanization. The coatings obtained by the AP-VPD contribute to surface roughness because the FAS vapors and atmospheric water are abundant during deposition processes. Such conditions favor vertical polymerization and formation of clustered deposits. The resulting nanoroughness was shown to affect wettability of modified surfaces. The influence of FAS backbone chain length on resulting surface nanotopography and how it affects surface wettability was investigated. Finally, the relationship between wettability and ice adhesion was examined. The strength of adhesion between frozen sessile droplets and modified substrates was investigated in tensile mode. A linear correlation between the ice-substrate adhesion strength and the macroscopic work of water-substrate adhesion was found. Graphical abstract Unlabelled Image Highlights • Epoxy and SU-8 were modified with a series of fluoroalkylsilanes from vapor phase. • Roughness volume parameters were employed for analysis of surface wettability • Surface nanotopography and chemistry was linked with triple phase line mobility and Cassie wetting. • Linear relationships between the work of adhesion and the ice adhesion strength were found. [ABSTRACT FROM AUTHOR]

Abstract It was found that, among these chitosan@TiO 2 (Cs@TiO 2) composites calcined at different temperatures (200, 300, 400, 500 and 600 °C), the composite calcined at 300 °C (Cs@TiO 2 -300) showed the best adsorption and photocatalytic activity. To eliminate the limitation of recycling catalyst nanoparticles, the PDMS-SiO 2 -Cs@TiO 2 composites with hydrophobic surfaces were prepared for dye degradation by embedding Cs@TiO 2 -300 nanoparticles into a PDMS-SiO 2 sol-gel system. More concretely, with pumice stone as the support of composites, the experiment was carried out in a reaction bed. When pumice stones were used as supports for PDMS-SiO 2 -Cs@TiO 2 composites, compared with its initial concentration, the concentration of dye solution decreased by 36% after 30 h of simulated sunlight irradiation. Additionally, the degradation efficiency of dyes hardly decreased after five cycles. The optical property and surface structure of PDMS-SiO 2 -Cs@TiO 2 were characterized by UV–Vis DRS and XPS, respectively. It is noteworthy that the UV–Vis DRS results indicated that the light absorption range of both Cs@TiO 2 -300 composites and PDMS-SiO 2 -Cs@TiO 2 composites had been broadened to the visible light region. Moreover, the XPS results indicated the existence of nitrogen (N) doped titanium on the surface of PDMS-SiO 2 -Cs@TiO 2 composites. Highlights • Immobilized PDMS-SiO 2 -chitosan@TiO 2 composites on pumice (pumice-PSCT) was prepared. • Degradation of methylene blue by pumice-PSCT was conducted in a reaction bed. • Stability of pumice-PSCT was ensured in recycle tests under simulated sunlight. • Visible light absorption of PDMS-SiO 2 -chitosan@TiO 2 was confirmed. [ABSTRACT FROM AUTHOR]

Abstract In this work, hydrophobic and corrosion behavior of multi-walled carbon nanotube (MWCNT) reinforced Ni-5 g/l MoSe 2 composite coatings on Ni substrate, synthesized by versatile single pot electro-codeposition process from a solution containing 0.1, 0.5 and 1 g/l of CNT, were compared with pure Ni coating as well as Ni-5 g/l MoSe 2 coating without CNT. All the composite coatings showed excellent hydrophobicity as compared to the pure Ni coating due to the rough surface along with codeposition of low surface energy materials, such as MoSe 2 and MWCNT, in the coating matrix. All the coatings showed improved anti-corrosion behavior as compared to the Ni substrate, and the coating with MoSe 2 and MWCNT further improved the corrosion resistance. Maximum corrosion resistance of the 0.1 g/l MWCNT reinforced Ni-5 g/l MoSe 2 coating among all the coatings could be attributed to the preferred atomically dense (111) plane, lowest lattice strain value, super-hydrophobic surface and higher amount of MWCNT codeposition. Graphical abstract Unlabelled Image Highlights • Codeposition of MoSe 2 and MWCNT facilitates compactness of the coating. • Excellent hydrophobicity for the Ni-MoSe 2 -MWCNTcoatings is observed. • Electrochemical activity influenced by crystal planes, strain, and hydrophobicity. • 0.1 g/l MWCNT added Ni-5 g/l MoSe 2 coating shows best corrosion efficiency. [ABSTRACT FROM AUTHOR]

Abstract The paper reports an investigation on the mechanical durability of textured thermoplastic surfaces together with their respective wetting properties. A range of laser-induced topographies with different aspect ratios from micro to nanoscale were fabricated on tool steel inserts using an ultrashort pulsed near infrared laser. Then, through micro-injection moulding the topographies were replicated onto polypropylene surfaces and their durability was studied systematically. In particular, the evolution of topographies on textured thermoplastic surfaces together with their wetting properties were investigated after undergoing a controlled mechanical abrasion, i.e. reciprocating dry and wet cleaning cycles. The obtained empirical data was used both to study the effects of cleaning cycles and also to identify cleaning procedures with a minimal impact on textured thermoplastic surfaces and their respective wetting properties. In addition, the use of 3D areal parameters that are standardised and could be obtained readily with any state-of-the-art surface characterisation system are discussed for monitoring the surfaces' functional response. Graphical abstract Unlabelled Image Highlights • The mechanical durability of textured surfaces is studied. • Laser-induced topographies were replicated onto polypropylene surfaces. • The surface energy and the Wenzel/Cassie-Baxter state of the textured surfaces were quantified. • The hydrophobicity decreased with the progressive abrasion of the topographies. • Standardised 3D areal parameters were correlated with surface wettability. [ABSTRACT FROM AUTHOR]

Highlights • Fluorine modification is successfully conducted on titanium dioxide particles. • Fluoro-organic chains contribute to a very hydrophobic surface. • Improved anti-icing property is obtained through a very hydrophobic surface. Abstract In this study, fluorine modification was successfully conducted on titanium dioxide (TiO 2) to enhance the anti-icing property through fabricating a very hydrophobic surface. TiO 2 was firstly modified with 3-methacryloxypropyl-trimethoxysilane (MPS) to introduce C C bonds. Then, dodecafluoroheptyl methacrylate (DFHMA) monomers were successfully grafted on the TiO 2 particles via C C bonds introduced by MPS. Herein, azobisisobutyronitrile (AIBN) was used as initiator to initiate the reaction. The chemical components of the TiO 2 particles were investigated by X-ray photoelectron spectroscopy (XPS). XPS analysis of fluorine-modified TiO 2 revealed that the fluorine content reached a peak value of 7.3%, while the water contact angle enhanced to a maximum value of 146°. This water contact angle value of 146° was dramatically increased by 131° in comparison with unmodified TiO 2 , indicating a very hydrophobic surface. The crystallization temperature of a water droplet on the corresponding fluorine-modified TiO 2 decreased to −19.4 °C (10.3 °C decrease in comparison with that of a water droplet on unmodified TiO 2). Also, the freezing delay time on the fluorine-modified TiO 2 is more than 25 min under the testing temperature of −10 °C, exhibiting excellent anti-icing property. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Examined alkyl chain length effect on wetting of phosphonate SAM-coated TiO 2 nanotubes. • Hill-Langmuir equation nicely fits contact angle vs carbon chain length variation. • Superhydrophobic functionalized TiO 2 nanotube arrays inhibit scale formation. • Scale-resistant surfaces survive five cycles of deposition-precipitation of salts. • Threshold hydrophobicity required to impede dissolved ion-surface interactions. Abstract Fouling of solid surfaces is a ubiquitous problem in industrial processes. As unwanted material accumulates on components, their function is impaired and costly repairs are required. Most fouling occurs from impurities present in water that are deposited when the water contacts a solid surface. It follows that if the adhesive forces at the water-solid interface are minimized, less fouling will result. In this study, we present a novel method to minimize fouling by fabricating a hydrophobic surface based upon self-assembled monolayer (SAM)-modified titanium dioxide nanotube arrays (TNTAs). We demonstrate a direct correlation between hydrophobicity and the formation of scale from dissolved salts by comparison of the surface's static contact angle and degree of precipitation deposition. Furthermore, by tailoring the surface hydrophobicity through employment of a wide variety of SAMs with different alkyl chain lengths, we determine the threshold level of hydrophobicity that inhibits fouling in the SAM-TNTA system; surfaces with a static contact angle greater than 144° display vastly increased fouling resistance. The surface morphology, surface composition, and stability of the alkyl phosphonic acid- and perfluoroalkyl phosphonic acid-SAM-TNTAs were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). [ABSTRACT FROM AUTHOR]

Graphical abstract A thin film of Ag nanocubes/graphene oxide hybrid placed on a hydrophobic surface can concentrate and adsorb organic pollutants for sensitive SERS detection by using the hydrophobic nature of a teflon surface, the large delocalized π-electron system in the graphene oxide and the high SERS activity of Ag nanocubes. Highlights • Analyte molecules can be effectively accumulated on the SERS-active sites using a hydrophobic surface. • Graphene oxide sheets are employed to adsorb target molecules for sensitive SERS detection. • Ag nanocubes have been densely modified on graphene oxide sheets to provide plenty of SERS hot spots. • Sensitive SERS detection of organic pollutants has been realized using the fabricated SERS system. Abstract Surface-enhanced Raman scattering (SERS) is a promising analytical technique with molecular "fingerprint" characteristic and high sensitivity. To achieve high sensitivity, analytes should be located in or around the so-called SERS "hot spots" that are normally formed in sub-10 nm gaps between the neighboring plasmonic nanostructures. Ordinary SERS substrates generally show low sensitivity to the molecules that have weak affinity to noble-metal surfaces. Here, we fabricate an effective SERS system that can concentrate and adsorb organic pollutants in water for sensitive SERS detection. Such a SERS platform is composed of a thin film of Ag nanocubes/graphene oxide hybrid covered on a small Cu foil, and the Cu foil is placed on a hydrophobic teflon surface. The Ag nanocubes/graphene oxide hybrid film is synthesized by growth of graphene oxide on a Cu foil using electrophoresis and subsequent assembly of Ag nanocubes on the graphene oxide in ethanol via van der Waals interactions. Organic pollutant molecules can be concentrated on the hybrid film by adding a droplet of aqueous analyte solution on the hybrid film and evaporating. Due to the hydrophobic nature of teflon surface, the droplet will shrink onto the hybrid film and realize the concentration of analyte molecules on a SERS platform. There exists large delocalized π-electron system in the graphene oxide, so the Ag nanocubes/graphene oxide hybrid can effectively adsorb a large number of analyte molecules. As there are plenty of nano-sized gaps between the Ag nanocubes that are densely attached on the graphene oxide sheets, high density SERS hot spots can be formed in the gaps. As a result, the Ag nanocubes/graphene oxide hybrid has shown high SERS activity with an enhancement factor of 3.9 × 108 and good signal uniformity (relative standard deviation ∼12%). It is further demonstrated that the hybrid SERS substrates have exhibited high SERS sensitivity to organic pollutants such as 4-chlorobiphenyl and methyl parathion, showing promising applicability in many fields as diverse as chemical analysis, environmental monitoring, and food safety inspection. [ABSTRACT FROM AUTHOR]

Highlights • Femtosecond laser texturing of copper. • Hierarchical structures on copper by combination of micro-machined patterns, sub-wavelength ripples and nanoparticles. • Femtosecond laser irradiation to achieve highly hydrophobic behaviour on copper. Abstract We report an experimental investigation on laser surface texturing of copper targets by Ti:Sa femtosecond laser pulses addressing their wetting response to water droplets. In particular, fs laser surface processing is used to developed hierarchical surface structures by writing parallel micro-trenches with a period of 50 μm at different laser pulse fluences. The laser irradiation simultaneously induces both the formation of laser induced periodic surface structures (LIPSS), in form of periodic ripples, and the random decoration with nanoparticles, resulting in the formation of a multiscale surface morphology. The morphological features of the samples are investigated and correlated with their wetting response through static contact angle measurements. Our findings evidence a progressive increase of the contact angle with the laser pulse fluence. The combination of the microscale trenches, written by laser line scanning, with the ripples patterns and the random nanoparticles decoration, formed on the surface, allow developing highly hydrophobic copper samples with contact angles reaching values around 160°, presenting potential interest for wettability applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nature-inspired hydrophobic Pglass surface was successfully prepared with POSS chemicals. • The POSS chemicals with longer alkyl chains gave Pglass surfaces with larger contact angle. • Air trapped on the Pglass surface was a factor for hydrophobicity as predicted by the Cassie model. • Surface roughness and low surface energy of POSS strongly enhanced Pglass surface hydrophobicity. Abstract Hydrophobic polyhedral oligomeric silsesquioxane (POSS) molecules were utilized for the surface coating to improve the hydrophobicity of the surface of phosphate glass (Pglass). To maximize the Pglass surface hydrophobicity, protrusions on the Pglass surface were successfully prepared by Pglass particles on the surface of the bulk Pglass to mimick the lotus leaf, which has a superhydrophobic surface. The results showed that the combination of hydrophobic coating by POSS and improved roughness prepared by Pglass particles with air trapped on the Pglass surface yielded significantly increased hydrophobicity close to superhydrophobicity of lotus leaf. Chemical stability tests using ethanol and acetone confirmed stability of POSS on the Pglass surface. This result was supported by the XPS data showing an increase of bridging oxygen on the Pglass surface due to the condensation reaction between the hydroxyly functional groups of the Pglass and POSS. The relatively longer hydrophobic functional group of isooctyl compared to that of the isobutyl on the POSS cages gave larger contact angles than that of conventional silane, indicating that the POSS chemicals used are able to effectively produce the so-called "umbrella effect" mechanism that covers the intrincic hydrophilic surface of the phosphate glass using bulky molecules and grafted hydrophobic POSS chemical functional groups. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The freezing process of water droplets under low pressure (2 kPa) on highly hydrophobic surfaces was reported. • Three different mechanisms, influenced by the substrate's temperature, control the frozen droplet disappearance. • Thermal instabilities and convective cells are observed on heated substrates. • A "Cassie ice state" can be reached on hydrophobic surfaces. Abstract We report on an experimental study of water droplets freezing on highly hydrophobic surfaces decorated by a random distribution of nanometric pores. We particularly analyze the influence of the substrate temperature ranging between 23 °C and 80 °C on the freezing phenomenon and the temporal stability of the resulting frozen droplets. The cooling and the subsequent spontaneous freeze of droplets were obtained by quickly reducing the pressure inside the cell from 101 kPa to 2 kPa. In all experiments the humidity rate was maintained very low (4%), allowing us to minimize its influence on the freezing process. The experimental results show that: (i) the freezing process is initiated by homogeneous nucleation near the gas-liquid interface, and is delayed by a factor between 2 and 3 on the substrates at the highest temperature. (ii) three different mechanisms, influenced by the substrate's temperature, lead to the disappearance of the frozen droplets. Fragmentation and sublimation of frozen droplets are observed for all substrates' temperatures. A melting of the ice shell is observed for droplets on substrate at 80 °C. This temperature appears as a minimal value from which we can expect to better control the water freezing and the frost formation on heated hydrophobic surfaces. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Unmodified polyamide 6.6, rarely studied for oil removal, separated oil/water. • 2D mesh and 3D nonwoven polyamide were systematically studied for oil removal. • Roles of 2D and 3D porous structures in intrusion pressures were illustrated. • Different contact angles determined intrusion pressures of 2D mesh and 3D nonwoven. • 3D netting was beneficial for oil/water separation in terms of intrusion pressures. Abstract Porous polyamide functionalized by plasma or various coatings has been investigated for oil/water separation. In literature, polyamide has rarely been studied for oil removal, and this work investigated the performance of bare polyamide 6.6 (nylon 6.6) in terms of the oil/water separation efficiency and the intrusion pressure, inspiring cost-effective solutions for large-scale oil removal in the industry. Both polyamide meshes possessing two-dimensional (2D) one-layer pores and nonwoven fabrics with three-dimensional (3D) irregular pores were found to be able to separate oil/water with a high efficiency above 98.5%. This finding was attributed to the dual underwater oleophobicity and underoil hydrophobicity of these polyamide samples. The roles of 2D and 3D structures in oil/water separation were illustrated, to provide a new insight into filter designing. Due to its greater intrusion pressure, the 3D netting structure was suggested as being more beneficial for oil/water separation than the 2D structure. [ABSTRACT FROM AUTHOR]

Highlights • The adsorption of S atom above the Fe atom of pyrite surface was most stable. • After there occurred partial oxidation on the pyrite surface, the hydrophilicity of the pyrite surface was weakened overall. • The pyrite surface changed from hydrophilicity to hydrophobic after complete oxidation of the pyrite surface from the macroscopic point of view. Abstract Using the first-principles method of density functional theory (DFT) and the plane-wave ultra-soft pseudopotential method, the adsorption process of water on a perfect pyrite surface and a surface with an adsorbed sulfur atom was calculated and simulated. The mechanistic role of sulfur formed during pyrite surface oxidation in the hydrophobicity of pyrite surfaces was explored. The simulation results showed that compared with the perfect pyrite surface, the surface with an adsorbed sulfur atom had an absorption energy that went from a negative to a positive value. The strong Fe S covalent bond was formed first between the surface pyrite iron atom and the adsorbed sulfur atom. Following this, a weak S O bond was formed between the sulfur and oxygen atoms of the water molecule. The adsorption of H 2 O on the pyrite surface was hindered by the generation of sulfur so that the surface with an adsorbed sulfur atom became hydrophilic. The simulation results are consistent with the results of wetting heat. The influence of sulfur adsorption on pyrite hydrophobicity was mechanistically revealed from the view of quantum chemistry. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new method is proposed to obtain wear-resistant hydrophobic surfaces. • The influences of different laser parameters on the wetting behaviors of water are investigated. • The structural hierarchy is essential for a robust superhydrophobic surface. • The mechanism of wear-resistant hydrophobic surfaces is analyzed. • This facile and low-cost method to produce wear-resistant surfaces can easily be extended to metal and nonmetal materials. Abstract In this study, a novel facile method, namely liquid-phase laser ablation, was proposed to obtain a robust hydrophobic surface. The cemented carbide sample was immersed in a fluorosilane solution and ablated by laser, while controlling the distance between the top surface of sample and liquid level. Then, a surface with good hydrophobicity could be obtained by one step using this technique. The effect of different laser processing parameters on the wettability of the sample surface was studied, and the water contact-angle (WCA) and the rolling angle (RA) could reach 148.4° ± 0.6°, 4.5° ± 0.5°, respectively, which indicated excellent hydrophobicity. Moreover, we found that the hydrophobic surface fabricated by the new method was more wear-resistant than that obtained by the laser texture and fluorination treatment. The hydrophobic surface exhibited excellent mechanical abrasion resistance as it maintained hydrophobicity even after being subjected to mechanical abrasion by hand-polishing 600 times with 1200 grit metallographic sandpaper. Moreover, the mechanism of wear-resistant was analyzed, which was attributed to the formation of the self-healing hydrophobic coatings with a certain thickness on the microstructures. This facile and low-cost method can not only be easily extended to other materials but also produce hydrophobic surfaces with robustness and self-healing properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-speed spin-coated cetyltrimethylammonium bromide (CTAB) solution passivated the surface of perovskite films. • Br- and ammonium groups contained in CTAB effectively bond ionic vacancy defects in the perovskite film during the passivation process. • After CTAB treatment, the quality of perovskite film was improved, and the optimized device had better photovoltaic performance. • Hydrophobic modification of the surface of perovskite films by CTAB improved the compatibility of the interface between perovskite layer and hydrophobic carbon electrode and enhanced the stability of PSCs. Organic–inorganic hybrid perovskite materials with mixed organic cations (FA x MA (1-x) PbI 3) have attracted intensive attention due to their superior optoelectronic properties. In this work, the FA 0.3 MA 0.7 PbI 3 perovskite film were synthesized and applied in perovskite solar cells (PSCs) based on carbon counter electrode (CCE). And a passivation approach for the perovskite/CCE interface is presented, using cetyltrimethylammonium bromide (CTAB). The quaternary amine and bromine ion of CTAB can fill the vacancy defects of FA/MA and iodine ion, respectively, leading to a more hydrophobic and smoother surface than the untreated film. The optimum device based on 0.5 mg/ml CTAB exhibited an short-circuit current density of 23.68 mA·cm−2 with a power conversion efficiency of 12.69%, which is superior to PSCs without CTAB. The long-term stability test in ambient atmosphere with 40% relative humidity reveals the higher stability of PSCs with the surface passivation, which is favorable for its commercial application. [ABSTRACT FROM AUTHOR]

Highlights • Water-evaporation-induced assembly technique was developed for fabrication of films. • CS and Mg-ACC are used to study the toughening mechanism of shells. • A theoretical model for the dispersion of Mg-ACC in chitosan matrix was proposed. • Crystalline transformation of Mg-ACC in chitosan enhanced properties of films. • Biocompatible, strong, and hydrophobic ACC-CS films were presented in our work. Abstract Amorphous calcium carbonate/chitosan (ACC/CS) nanocomposite films containing Mg-ACC (0–100 wt%) are prepared by simple natural evaporation-induced assembly. The influence of Mg-ACC content on the mechanical properties as well as cross-section of ACC-CS nanocomposite films were systematically investigated. The nanocomposite films exhibit an excellent mechanical property at Mg-ACC contents of 80 wt% compared to ordinary calcium carbonate/chitosan composites. With content of Mg-ACC increasing, the mechanical properties of ACC-CS nanocomposite films were further increased, reaching a maximum when the content of Mg-ACC to 80 wt%. Strength and Young's modulus of the 80 wt% ACC-CS nanocomposite film reach 121.67 MPa and 31.96 GPa, respectively, which is 2.3 and 5.1 times higher than that of the pure CS film. After undergoing Mg-ACC crystal transformation when the Mg-ACC content is greater than 80 wt%, the smooth structure was transformed into crystal-like agglomerates, which deteriorates mechanical properties. Furthermore, the as-prepared nanocomposite films show excellent hydrophobicity and high biocompatibilities for boosting the growth of Cell-293T. In addition, we also proposed a physical model for the dispersion of Mg-ACC in CS matrix, which could better explain the enhancement of the mechanical properties of nanocomposite films. The above results provide a comprehensive understanding of the development of high-performance bionic nanocomposites loaded with high nanofillers. [ABSTRACT FROM AUTHOR]

Hydrophobic paper decorated Ag nanoparticles (NPs) with a uniform distribution was fabricated in an oil-paper-aqueous triphasic system via a facile in situ interfacial reduction approach. Interestingly, the Ag NPs formed at the paper/aqueous interface could migrate to the oil/paper interface. Moreover, these Ag NPs would not continue to migrate away the paper surface into the oil phase but was completely confined in the solid paper matrix. This phase confinement of migrated Ag NPs in the paper matrix creates abundant 3D hot spots for plasmonic enhancement. The obtained Ag-loaded paper exhibits an excellent SERS activity, reliable reproducibility and autofluorescence suppression effect, which enabling it as a promising platform for qualitative and quantitative SERS study. Due to its condensation effect, the hydrophobic paper surface can be used as a concentrator to enrich water-soluble analytes over the SERS active domains for highly sensitive detection (10 −9 mol/L −1 ). Furthermore, the Ag-loaded paper combined with the feature of chromatography and plamon-enhanced optical signals possesses ability to perform synchronous separation and surface-enhanced Raman scattering (SERS) detection of complex samples. [ABSTRACT FROM AUTHOR]

Here, electron-transporting semiconducting organic channels made of N,N′-1H, 1H-perfluorobutyl dicyanoperylenecarboxydiimmide (PDIF-CN 2 ) molecules were thermally evaporated on flexible polyethylene-naphtalate (PEN) plastic substrates equipped with gold (Au) electrodes. This multilayer structure represents the basic component for the fabrication of staggered top-gate n-type organic thin-film transistors (OTFTs) to be completed with the addition of a polymeric dielectric layer and an aluminum gate electrode. PEN substrate was treated with hexamethyldisilazane (HMDS) in order to make it more hydrophobic. Indeed, the hydrophobized surface of the plastic substrate was shown to induce a more ordered supramolecular structure of the semiconductor layer during the evaporation process. The hybrid organic/inorganic formally trilayer non-passivated OTFT structure was successfully profiled in a single run through ToF-SIMS depth profiling experiments with low energy cesium ions. High mass molecular fragment ions were obtained and used as indicators of interfaces, leading to an increase of information on molecular specificity. The HMDS surface modification was clearly detected and spatially located. Finally, a chemometric approach was also adopted to evaluate depth profiling data. In particular, principal component analysis (PCA) and K-means algorithm were tested as innovative method for the identification of molecular fragments useful for the OTFT multi-layer structure characterization and the determination of the number of OTFT layers, respectively. [ABSTRACT FROM AUTHOR]

In this investigation, a MoO 3 -SiO 2 nanocomposite coating was developed on a 316L stainless steel (SS) substrate by double-cathode glow discharge deposition. Chemical valence states, phase composition and microstructure features of the nanocomposite coating were studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the nanocomposite coating was composed of a mixture of crystalline MoO 3 and amorphous phases, in which amorphous SiO 2 phase was embedded between the hexagonal-structured MoO 3 grains with an average grain size of ∼8.4 nm. Nanoindentation and scratch tests, together with SEM and TEM observation of locally deformed regions, indicated that the nanocomposite coating exhibited high load-bearing capacity due to a combination of high hardness and good adhesion. Contact angle measurements suggested that the nanocomposite coating was more hydrophobic than uncoated 316L SS. The anti-bacterial activity of the MoO 3 -SiO 2 nanocomposite coating against two bacterial strains ( E. coli and S. aureus ) was determined by the spread plate method. This showed that both bacterial strains exposed to the coating suffered a significant loss of viability. The influences of sulfate-reducing bacteria ( SRB ) on the electrochemical behavior of the MoO 3 -SiO 2 nanocomposite coating in modified Postgate’s C seawater (PCS) medium were investigated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The electrochemical tests revealed that the coating had a greater resistance to microbiologically influenced corrosion induced by SRB than uncoated 316L SS. This was corroborated by electrochemical testing (potentiodynamic polarization and EIS), in conjunction with SEM observations of the corroded surfaces. [ABSTRACT FROM AUTHOR]

We report the effects of surface patterning on the wetting of Pt 57.5 Cu 14.7 Ni 5.3 P 22.5 and Pd 43 Cu 27 Ni 10 P 20 metallic glasses. To maintain the integrity of surface chemistry of the metallic glasses, we optimize thermoplastic patterning protocol and use chemical-free demolding. Our results show that single-scale surface microstructures can render inherently hydrophilic Pt 57.5 Cu 14.7 Ni 5.3 P 22.5 metallic glass hydrophobic when its chemical state is preserved. We also observe that because of oxidation, Pd 43 Cu 27 Ni 10 P 20 metallic glass remains hydrophilic regardless of its surface topography, though its wettability evolves (i.e. decreases) with time due to airborne contamination. These results suggest that to draw an unambiguous conclusion about the role of surface texture, concomitant changes in surface chemistry must be avoided. [ABSTRACT FROM AUTHOR]

Reproducible and controllable methods of modifying titanium surfaces for dental and orthopaedic applications are of interest to prevent poor implant outcomes by improving osseointegration. This study made use of a femtosecond laser to generate laser-induced periodic surface structures with periodicities of 300, 620 and 760 nm on titanium substrates. The reproducible rippled patterns showed consistent submicron scale roughness and relatively hydrophobic surfaces as measured by atomic force microscopy and contact angle, respectively. Transmission electron microscopy and Auger electron spectroscopy identified a thicker oxide layer on ablated surfaces compared to controls. In vitro testing was conducted using osteosarcoma Saos-2 cells. Cell metabolism on the laser-ablated surfaces was comparable to controls and alkaline phosphatase activity was notably increased at late time points for the 620 and 760 nm surfaces compared to controls. Cells showed a more elongated shape on laser-ablated surfaces compared to controls and showed perpendicular alignment to the periodic structures. This work has demonstrated the feasibility of generating submicron features on an implant material with the ability to influence cell response and improve implant outcomes. [ABSTRACT FROM AUTHOR]