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Triboelectric nanogenerators (TENGs) are useful for harvesting clean and widely distributed water droplet energy with high efficiency. However, the commonly used polymer films in TENGs for water droplet energy harvesting have the disadvantages of poor breathability, poor skin affinity, and irreparable hydrophobicity, which greatly hinder their wearable uses. Here, we report an all-fabric TENG (F-TENG), which not only has good air permeability and hydrophobic self-repairing properties but also shows effective energy conversion efficiency. The hydrophobic surface composed of SiO2 nanoparticles and poly(vinylidenefluoride-co-hexafluoropropylene)/perfluorodecyltrichlorosilane (PVDF-HFP/FDTS) exhibits a static contact angle of 157° and displays excellent acid and alkali resistance. Because of its low glass transition temperature, PVDF-HFP can facilitate the movement of FDTS molecules to the surface layer under heating conditions, realizing hydrophobic self-repairing performance. Furthermore, with the optimized compositions and structure, the water droplet F-TENG shows 7-fold enhancement of output voltage compared with the conventional single-electrode mode TENG, and a total energy conversion efficiency of 2.9% is achieved. Therefore, the proposed F-TENG can be used in multifunctional wearable devices for raindrop energy harvesting.

Pseudomonas aeruginosa (P. aeruginosa) has been implicated in the attachment and formation of marine biofilms which initiate biofouling and biocorrosion. To this end, several hydrophobic and superhydrophobic coatings have been suggested for anti-bacterial application, but some possess toxic substances which affect useful aquatic lives. Thus, the aim of this study was to appraise the anti-bacterial and anti-corrosion performance of hydrophobic perfluorodecyltrichlorosilane (FDTS)-modified poly (dimethylsiloxane) (PDMS)-ZnO coating using P. aeruginosa. The surface analytical, physico-chemical and electrochemical techniques were used to investigate the properties of the coatings. Results show that FDTS-modified PDMS-ZnO coating displayed higher resistance to adhesion of P. aeruginosa biofilm and better corrosion resistance performance than the unmodified coating. The outstanding performance of FDTS-modified coating was attributed to the low surface activity of FDTS which increased the kinetic barrier between the coating surface and biofilm. It is therefore anticipated that these results would provide insight in the design of future anti-bacterial coatings for marine application.

Sulfate-reducing bacteria (SRB) has been pointed out as one of the causative agents of microbial induced corrosion in the marine environment. To address this problem, novel strategies are being experimented as against the earlier methods which have been banned due to their toxic effects on useful aquatic lives. Thus, the aim of this study was to investigate the effect of non-toxic perfluorodecyltrichlorosilane (PFDTS) on resistance of hydrophobic poly(dimethylsiloxane)/phosphoric acid-treated zinc oxide (PDMS/PA-treated ZnO) coatings to SRB-induced biofouling and corrosion. The surface features of the coatings before and after exposure to SRB/NaCl solution were analyzed by scanning electron microscopy (SEM). Wettability of the coatings before and after exposure was also measured. The interaction of SRB with the coatings was investigated by FTIR spectroscopy. The resistance performance of the modified coatings against SRB-induced corrosion was monitored by electrochemical impedance spectroscopy (EIS). The EIS measurements revealed that 0.20 g PFDTS-based coating displayed highest corrosion resistance with impedance modulus of 6.301 × 1010 after 15 d of exposure to SRB/NaCl medium. The results were corroborated by surface and chemical interaction analyses, and thus, indicate that 0.20 g PFDTS-modified PDMS/PA-treated ZnO coating has potentials for excellent SRB-induced corrosion resistance and anti-biofouling performance.

Las propiedades fisicoquímicas del agua ligera (H2O) y del agua pesada (D2O) difieren en cierta medida debido a las diferencias que surgen de los efectos de los isótopos. Para comprender mejor los efectos de los isótopos en las interacciones hidrófobas, informamos la comparación experimental directa de las interacciones hidrófobas en agua ligera versus agua pesada entre superficies de mica hidrofobizadas molecularmente extendidas y lisas utilizando un Aparato de Fuerzas de Superficie (SFA). En este estudio sintetizamos superficies hidrófobas estables, lisas y fácilmente reproducibles mediante la deposición de monocapas de perfluorodeciltriclorosilano (FDTS) sobre superficies de mica activadas por plasma utilizando la técnica de deposición de vapor molecular (MVD). La humectabilidad y la morfología de la superficie de las muestras de mica recubiertas con FDTS se controlaron directamente utilizando una célula de ángulo de contacto y un microscopio de fuerza atómica (AFM). La inestabilidad en la curva de fuerza se observa durante el acercamiento y la retracción de las superficies en los experimentos SFA y nuestros experimentos preliminares de espectroscopia de fuerza demostraron que la magnitud de la interacción hidrofóbica entre las superficies de mica recubiertas con FDTS es 20% más fuerte en agua pesada que en agua ligera. Nuestros resultados indican que los perfiles de fuerza-distancia obtenidos para los casos tanto de H2O como de D2O no pudieron ser descritos razonablemente por la teoría clásica de Derjaguin − Landau − Verwey − Overbeek (DLVO) y la fuerte adhesión medida entre las capas FDTS-FDTS que interactúan es dominado por las interacciones hidrófobas.

Wettability of surfaces used in microdevices, either on the fabrication of fluidic passages or integration of sensing and actuating elements can impact the flow. The easiness of fabrication may dictate the materials and processes to use, that can subsequently have their surface wettability spatially controlled. The work reports surface wettability modification (SWM) by room temperature chemical vapor deposition (CVD) with HMDS (hexamethyldisilazane) and FDTS (perfluorodecyltrichlorosilane) on flat surfaces of silicon (Si), glass, SU-8 photoresist and PDMS (polydimethylsiloxane). The effect of SWM has been evaluated by the measurement of contact angles (CA) of 6 μL droplets of deionized water and phosphate-buffered saline buffer (PBS). Time of surface exposure and evolution of CA after modification have been investigated for each pair surface/fluid. The time of surface activation with HMDS or FDTS and the chemical affinity of these to the surface are seen to govern the efficiency of surface coverage and consequently the efficiency and stability of SWM. For both HMSD and FDTS SWM, hydrophilic surfaces (glass and Si) became more hydrophobic (CA rising from 20° up to ˜70°) while SU-8 hydrophobic surfaces became more hydrophilic (CA decreasing from 120° down to ˜100°) upon 30 min activation. PDMS surfaces shows no relevant SWM after activation with HMDS nor with FDTS. SWM of Si surfaces has remained irreversible following CVD exposure (HMDS and FDTS) for at least 65 h.

Asymmetric membranes with a thin, small pore size upper layer have the potential to facilitate a high vapor flux while maintaining high liquid entry pressure, which is critical for membrane distillation (MD) and thermo-osmotic energy conversion (TOEC) processes. Here, asymmetric mixed cellulose ultrafiltration membranes were modified with perfluorodecyltrichlorosilane to produce 50 nm and 25 nm pore size membranes with highly hydrophobic surfaces (contact angle >115°) and unprecedented liquid entry pressures >24 bar. The 50 nm membrane performance was evaluated in a series of MD and TOEC mode experiments, where the membrane dense layer faces the hot feed stream or the cold permeate stream, respectively. Our results demonstrate that the membrane water vapor permeability coefficient is significantly higher when operating in MD mode (1.7 × 10−7 kg m−2 s−1 Pa−1) compared to TOEC mode (0.9 × 10−7 kg m−2 s−1 Pa−1) at a similar temperature difference of 39 °C, suggesting an additional resistance to vapor flux in TOEC mode. We developed a model for mass and heat transfer through the membrane to explain the change in performance due to reversing the asymmetric membrane orientation. As expected, the model and the experimental results show a linear increase in the water vapor permeability coefficient with respect to temperature difference across the membrane for the MD orientation. However, for the TOEC orientation, the water vapor permeability coefficient was relatively constant across all the temperature differences investigated. Our results predict that the additional mass transport resistances in TOEC mode decrease as the transmembrane temperature gradient decreases. We conclude with a discussion on the implications of using asymmetric membranes for MD and TOEC processes.

The self-assembled monolayer FDTS (1H,1H,2H, 2H-Perfluorodecyltrichlorosilane) is presented as suitable dewetting coating material for an electrowetting on dielectrics (EWOD) controlled silicon photonics switch deployed in fiber optic telecommunication systems. The anti-sticking characteristics of Perfluorodecyltrichlorosilane (FDTS) are compared to those of polytetrafluoroethylene (PTFE) as most common dewetting coating for EWOD devices. It is shown that FDTS could outperform other materials such as PTFE when an extremely thin, long-term stable, and uniform layer is required. In the specific case, FDTS is applied in vapor phase as anti-sticking coating to the active optical surface of the integrated silicon photonics switch thus enabling the EWOD driven liquid motion. The suitability of the coating is presented by contact angle measurements and durability tests carried out with the switching liquids. Finally, it is demonstrated by optical measurements that the FDTS coating has a neglectable influence on the optical switching performance.

Poly(dimethylsiloxane)-ZnO coatings modified with different amounts of perfluorodecyltrichlorosilane (FDTS) were prepared using sol-gel technique. The results of field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) examinations showed that the surface structures and roughness of the coatings were respectively influenced by the increasing addition of FDTS. The water contact angle measurements showed maximum value of 130.52° with the 0.10 g FDTS-modified coating sample. The X-ray photoelectron spectroscopy (XPS) results indicated the coatings’ hydrophobicity was also influenced by surface chemistry. The FTIR-ATR characterization results showed there was remarkable increase in the crystallinity of 0.10 g FDTS-modified coating after modification, and was confirmed by differential scanning calorimetry (DSC) analysis of crystallization temperature and the X-ray diffraction (XRD) results with an estimation of 71.29% percent crystallinity. The mechanical properties of the coatings were also conducted. The EIS measurements for anti-corrosion behavior showed that 0.10 g FDTS-modified coating had the highest barrier performance and lowest rate of degradation. Indeed, the obtained data have demonstrated that 0.10 g (≈ 0.18%) FDTS produced the most significantly effect on the surface and barrier properties of the coatings and thus, can effectively be used for anti-corrosion application in the marine environments.

Superhydrophobic poly(ethylene terephthalate) (PET) fabrics were firstly fabricated by one-pot in situ Stober reaction of tetraethylorthosilicate (TEOS) and dodecyltrimethoxysilane (DTMS), in which the as-formed silica particles roughened the fiber surfaces and the hydrolyzed dodecyltrimethoxysilane hydrophobized the fabrics. Then the superhydrophobic fabrics were turned superamphiphobic after modification with perfluorodecyltrichlorosilane (PFDTS), with water and oil contact angles higher than 150°. The synergistic hydrophobization of DTMS, PFDTS and PDMS made the roughened fabrics easy to be superamphiphobic using very low concentration of PFDTS. Meanwhile, the as-obtained superamphiphobic fabric showed excellent chemical robustness even after exposure to different chemicals, such as acid, base, and salt. Importantly, the fabrics were durable to 100 cycles of laundries, 1000 cycles of mechanical abrasion as well as long time exposure to UV irradiation without apparently changing the amphiphobicity. Also, the surface of the superamphiphobic fabrics showed excellent blood stain resistance properties.

The random nature of dropwise condensation impedes spatial control hereof and its use for creating microdroplet arrays, yet here we demonstrate the spatial control of dropwise condensation on a chemically homogeneous pillar array surface, yielding ∼8000 droplets/mm2 under normal atmospheric pressure conditions. The studied pillar array surface is defined by photolithography and etched in silicon by deep reactive ion etching. Subsequently, the surface is covered with a self-assembled monolayer of perfluorodecyltrichlorosilane (FDTS) to render the surface hydrophobic. To obtain a perfect droplet array, with one droplet per pillar, we exploit a phenomenon where the water vapor flux is focused on the apexes of surface asperities by diffusion while matching the nucleation point density to the array dimensions. Matching is here achieved through the variation of interpillar distance and vapor flow conditions.

A helium (He) atmospheric-pressure dielectric barrier discharge jet (DBDjet) is used to pattern 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDTS)-coated cellulose paper with a shadow mask. DBDjet processing under appropriate conditions can be used to form hydrophilic patterns. The properties of the DBDjet-patterned PFDTS-coated paper are investigated through water contact angle measurement, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), and the results indicate the successful deposition and removal of PFDTS before/after DBDjet treatment. The successful routing and mixing of liquid in the hydrophilic stripes are demonstrated, and a glucose concentration colorimetric test is demonstrated using this DBDjet-patterned PFDTS-coated paper.

In this work, a facile approach of covalent layer-by-layer assembly was applied to fabricate a bilayer nanofilm which renders roughened copper foam superhydrophobic with robust performances. Before constructing the bilayer nanofilm, the surface of the foam was roughened by using KOH–K2S2O8 as the oxidation system, giving rise to hierarchical structures of flower-like protrusions and petals. A multifunctional polymeric nanofilm, capable of resisting copper corrosion and serving as an activated interface simultaneously, was first introduced onto the copper surface by heating self-assembled monolayers (SAMs) of one triazinedithiolsilane compound (designated as TESPA). Then, perfluorodecyltrichlorosilane (abbreviated as PFDTCS) was anchored onto the TESPA-modified copper surface. Consequently, a bilayer nanofilm of PFDTCS–TESPA is generated on the hierarchical foam that possesses outstanding superhydrophobic capability. The as-prepared foam exhibits excellent reusability and separation efficiency. After fifty recycles, the separation efficiency exceeds 98% while the surface still retains remarkable superhydrophobicity. The improved efficiency and recycle number are outstanding compared to those of similar systems reported previously. X-ray photoelectron spectroscopy (XPS) was conducted to reveal the mechanism of the robust performances of the bilayer-coated foam. The results show that TESPA can react with copper oxide (CuO) through SH groups yielding TESPA SAM. Upon heating, the newly formed disulfide units (–SS–) and siloxane networks (SiOSi) of the TESPA polymeric nanofilm protect the copper; the outward silanol groups (SiOH) endow the surface with activating ability. PFDTCS can covalently bond to the TESPA polymeric nanofilm via these SiOH groups. The specific arrangement of PFDTCS–TESPA and the chemical bonds of Cu(I)S, as well as the three-dimensional (3D) cross-linked textures of –SS– units and SiOSi networks, cooperatively enhance the chemical durability of the bilayer. The design strategy of preparing the bilayer nanofilm via an interlayer (e.g., TESPA as a molecular adhesive displayed in this work) can also be applied in other superhydrophobic systems for improved long-term utilization.

A characterization method, which allows visual observation of the surface area that is wet by a liquid on a roughened surface, called the solid fraction (fs) in the Cassie–Baxter model was developed. To this end, superhydrophobic polystyrene (PS) webs (contact angles ∼170°, sliding angles ∼3°) were fabricated via electrospinning and subsequent coating with perfluorodecyltrichlorosilane (PFDTS). The theoretical solid fraction of the Cassie–Baxter model, fs, was calculated from the equation. Microscopic images of the PS webs were converted into black and white binary images after adjusting the gray-scale of the images to match the bright area fraction with the theoretical fs. For visual observation of the actual solid fraction, a drop of an aqueous solution with a hydrophobic fluorescent dye was rolled on the surface. Traces of the dye on the PS surface were analyzed by fluorescence microscopy to measure the actual solid fraction (fdyes) that was wet by the aqueous solution. The fdyes value corresponded well with the theoretical fs for the webs with superhydrophobic characteristics.

The inefficient cleanup of viscous heavy oil is thought as a worldwide problem because of its poorer fluidity at room temperature. Herein, we make full use of the photothermal performance to harvest solar energy and convert heat into heavy oil, thus reducing significantly oil viscosity and realizing rapid oil remediation. Specially, the polydopamine as photothermal components, titanium dioxide and perfluorodecyltrichlorosilane as superhydrophobic/superoleophilic source are introduced into the melamine-formaldehyde sponge by deposition method. To be applicable in the marine environments with winds and waves, the bottom side of this sponge subjected to UV irradiation is transferrable from superhydrophobicity to superhydrophilicity. The Janus sponge can keep the balance of movement and never overturned under the action of wind force, thereby enabling this sponge to absorb consecutively spilled heavy oil from marine system. With one simulated solar irradiation, the top and bottom of Janus sponge are heated to a suitable temperature of 90.7 and 70.2 °C, respectively. Relied on these advantages, the Janus sponge can effectively reduce the viscosity of spilled heavy oil and enhance its fluidity, which allow for quick heavy oil absorption up to nearly 12 times of own weight. Meanwhile, it can be also compressed for recycled uses.

The removal of water-soluble organics from aqueous feeds is required in numerous practical applications, including bioresource processing, fermentation, and wastewater treatment. To this end, direct contact membrane distillation (DCMD) has been proposed as a separation technology. DCMD utilizes hydrophobic membranes – typically, comprising perfluorocarbons – which, when placed between a warm feed and a cold permeate, prevent mixing due to the robust entrapment of air inside the (membranes') pores. Thus, the membranes allow only pure water vapor to transport across, following the thermal gradient. Here, we assessed DCMD for separating organics from aqueous feeds in light of organic fouling by utilizing ethanol and perfluorodecyltrichlorosilane (FDTS) as the surrogate organic and hydrophobic coating, respectively. We investigated the adsorption of ethanol onto FDTS-grafted surfaces and membranes exposed to alcohol-water mixtures. Using the surface force apparatus, we found that the magnitude of hydrophobic forces between ultra-smooth FDTS-grafted mica surfaces in water-alcohol mixtures decreased with the increasing alcohol content. To simulate a practical DCMD scenario, we utilized FDTS-grafted polycarbonate membranes to separate a pure water reservoir from another containing 0.6 M NaCl and alcohol. For the 0% alcohol case, the membranes robustly separated the reservoirs for over a week, whereas even for ≥ 0.1% ethanol content, the membranes leaked within

Magnesium alloys have been widely employed for structural parts of aircrafts and automobiles to reduce their weight. However, magnesium alloys are easily corroded, thus practical applications always require protective coatings to guarantee satisfactory lifetime. In this study, we applied oil-impregnation and hydrophobizing to traditional plasma electrolytic oxidation (PEO) of magnesium alloy. Nanoporous hydroxide surface structure is fabricated by hydrothermal treatment of PEO-treated Mg alloy, then the self-assembled monolayer of perfluorodecyltrichlorosilane (FDTS) is coated for the hydrophobizing. The immiscible oil impregnation into the PEO-treated oxide layer with hydrothermal treatment and hydrophobizing significantly enhances the corrosion resistance as well as the mobility of water droplet on the surface. In addition, since the oil layer on the nanoporous surface inhibit the direct contact and penetration of corrosive liquid to the oxide layer, the oil-impregnated surface shows less degradation in corrosive liquid with long-term immersion than hydrophobic and superhydrophobic surface without oil-impregnation. These results indicates that oil-impregnated surface of Mg alloy has durable and robust anti-corrosion property.

The superamphiphobic surfaces with extreme repellency to liquids are very attractive in many fields, but their fabrication processes are always low effective and expensive. So it is still a challenge to create the superamphiphobic surfaces by simple, time saving and universal method. In this work, the mossy zinc (Zn) filaments, a promising re-entrant structure, was rapidly constructed on various metal surfaces by electrochemical deposition approach. After modification by 1H,1H,2H,2H- perfluorodecyltrichlorosilane (PFDTCS), the Zn@PFDTCS coating exhibited superamphiphobicity in air. The correlation between the morphology of Zn filaments and electrochemical deposition parameters has been studied. The superamphiphobic surface with contact angle higher than 154°, sliding angle lower than 5° and adhesive force lower than 0.043 mN to water and hexadecane was obtained, when the current density was 1.78 A ·dm−2, the mass fraction of zinc was 0.71 wt% and the deposition time was 40 min. Furthermore, the Zn@PFDTCS 2D-meshes were used to collect oil droplets under water and cut water droplet in oil due to their superoleophilicity under water and superhydrophobicity under oil. We anticipated that the simple and rapid method guides the design of perfect artificial superamphiphobic surfaces in practical application.

We demonstrate the use of wafer-scale nanolithography based on block-copolymer (BCP) self-assembly for the fabrication of surfaces with enhanced wetting properties. All classes of wetting behaviour derived from the same BCP nanolithography step are demonstrated. An in situ etch mask is defined by self-assembly of polystyrene (PS) and dimethylsiloxane (PDMS) domains to form a predominantly hexagonal array with pitch size (72 +/- 3) nm. The subsequent branched processing scheme, exclusively employing dry chemistry and reactive ion etching (RIE), allows the fabrication of nanoholes, nanopillars, or high aspect ratio nano-hoodoo features (overhang profile structures) with a diameter below 100 nm. The surfaces are finally functionalized with either hydrophobic surface chemistry by self-assembly from the precursor perfluorodecyltrichlorosilane (FDTS), or hydrophilic surface chemistry obtained by oxygen plasma treatment. The different texture and surface chemistry configurations are characterized with respect to their wetting properties with water, alkanes and organic oils. While, both nano-pillar and nano-hole surfaces feature excellent superhydrophobic properties with water contact angles (WCAs) exceeding 170 degrees and roll-off angles below 5 degrees, only the nano-pillar surfaces exhibit convincing superhydrophilicity with WCAs below 5 degrees. The repellency of low surface tension liquids known as amphiphobicity is demonstrated for the nano-hoodoo surfaces.

Although there are many viable approaches to induce hydrophobicity, a superhydrophobic surface could only be fabricated by combination of surface chemistry modification and roughness enhancement. In this study, surface roughness was obtained by 12 nm SiO2 nanoparticles (NPs) which were chemically modified using a self-assembled monolayer of perfluorodecyltrichlorosilane. The SiO2 NPs which were rendered hydrophobic, then successfully dispersed into a poly silicon (silsesquioxane) matrix at varying concentrations from 0.5 to 4%. The NPs dispersed polymer suspension was then spray coated on to glass and aluminum coupons in order to achieve polymer thin film nanocomposites. The results were revealed a superhydrophobic surface with a water contact angle exceeding 178 with low hysteresis and bouncing water droplet behavior. Furthermore the composite film reliability (hot-humid and ice build-up) was tested in an environmental control chamber by precisely adjusting both temperature (85 degrees C) and relative humidity (85 RH). Taber abrasion testing was applied in order to gain insights into the abrasion resistance of nanocomposite film. Finally, ice formation was simulated at 20 degrees C on the superhydrophobic nanocomposite film coated substrates. (C) 2015 Elsevier B.V. All rights reserved.

In recent years, the design of highly liquid-repellent surfaces has received great attention. Here, we report a facile method of creating a surface that repels both water and oils; using simple spray-coating, a hierarchically rough ZnO–PDMS composite can be applied to a variety of substrates that serves as a nanostructured surface for further modification. We applied an overcoating of either a fluoropolymer (Teflon AF) or perfluorodecyltrichlorosilane to fabricate low energy surfaces that repel water and oil for a variety of potential uses. The resultant surfaces are superomniphobic, have static contact angles of >140° for droplets of both liquids, and have low sliding angles for both water and oil droplets

Droplet array chips were realized using an alignment-free fabrication process in silicon. The chips were textured with a homogeneous nano-scale surface roughness but were partially covered with a self-assembled monolayer of perfluorodecyltrichlorosilane (FDTS), resulting in a super-biphilic surface. When submerged in water and withdrawn again, microliter sized droplets are formed due to pinning of water on the hydrophilic spots. The entrained droplet volumes were investigated under variation of spot size and withdrawal velocity. Two regimes of droplet formation were revealed: at low speeds, the droplet volume achieved finite values even for vanishing speeds, while at higher speeds the volume was governed by fluid inertia. A simple 2D boundary layer model describes the behavior at high speeds well. Entrained droplet volume could be altered, post-fabrication, by more than a factor of 15, which opens up for more applications of the dip-coating technique due to the significant increase in versatility of the micro-droplet array platform.

The use of epoxy and polyurethane coatings as marine topcoats, have been influenced by their inherent high surface energy property which increases their affinity to water and microorganisms. Thus, their susceptibility to degradation is enhanced. Because of this defect, recently, nanostructured hydrophobic and superhydrophobic polysiloxane coatings are being preferred as topcoats. But the appropriate nanoparticle size and matrix:filler ratio which provide guide for the design of desired topcoats are scarcely available. In view of this, a series of hydrophobic and superhydrophobic coatings were prepared by sol–gel process based on perfluorodecyltrichlorosilane (FDTS), different nanoZnO particles and poly(dimethylsiloxane) (PDMS):nanoZnO ratios. The liquid repellency, surface morphology and roughness of the coatings were conducted by use of contact angle goniometer, field emission scanning electron microscopy and atomic force microscopy, respectively. Additionally, the electrochemical and salt spray corrosion tests were conducted. According to the results, modifications of the coatings showed that anticorrosion performance was considerably influenced by the surface properties which were dependent on nanoZnO size and PDMS:nanoZnO ratio. Remarkably, the optimum effect was observed on the superhydrophobic coating based on 30 nm ZnO and 1:1 ratio. This displayed highest anticorrosion performance, and is therefore recommended as a guide for the design of marine topcoats.

The study aims to examine the influence of different surface treatments on the drag coefficient of free-falling spheres in water. The spheres used in the experiment are classified into four categories and labelled as: ref – no surface treatment, FDTS – coated with hydrophobic perfluorodecyltrichlorosilane (FDTS) coating, E8 – 8 minutes etched in ferric chloride (FeCl3) and E32 – 32 minutes etched in FeCl3. No significant difference is observed in drag coefficient of the etched spheres compare with the reference sphere. However, the FDTS sphere’s drag coefficient was increased by 13%.

The recent increased interest in the various applications of superhydrophobic surfaces necessitates investigating ways of how this property can be enhanced further. Thus, this study investigated how superhydrophobic properties can be enhanced through the formation of anodic alumina nanostructures on 5052 aluminum alloy. A multistep anodizing process that alternates two different anodizing modes, mild anodization (MA) and hard anodization (HA), with an intermediate pore-widening (PW) process was employed. Multistep anodization was employed in two different ways: an MA &rarr, PW &rarr, HA process and an HA &rarr, MA process. Both routes were conducted with PW durations of 40, 50, and 60 min. The well-defined nanostructures were coated with a self-assembled monolayer (SAM) of FDTS (1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane). The contact angle values of water droplets were maximized in the pillar-like nanostructures, as they have a less solid fraction than porous nanostructures. With this, the study demonstrated the formation mechanism of both nanoscale pillar and nanoscale hierarchical structures, the wettability of the superhydrophobic surfaces, and the relationship between PW duration time with wettability and the solid fraction of the superhydrophobic surfaces.

This paper describes a reliable method for fabrication of stable gold patterns embedded in polydimethylsiloxane (PDMS) using a direct peel-off process. Two different surface modifications with self-assembled monolayers were carried out for easy and reliable transfer of Au micro-patterns to the PDMS: (1) perfluorodecyltrichlorosilane on a Si substrate for easy release of the Au patterns from the Si substrate, and (2) (3-mercaptopropyl)trimethoxysilane on the Au patterns to promote the adhesion between the Au patterns and PDMS. Au features as small as 2 μm, in shapes of line and dots, were successfully transferred from the Si substrate to the PDMS over a 3-inch wafer. Transfer of Au patterns to PDMS using the dry peel-off process did not cause any contamination of PDMS, typically seen in wet chemical methods. Finally, the stability of the Au patterns embedded in PDMS was confirmed by the Scotch-tape adhesion test.

In this work, a hydrophobic self-assembled monolayer, perfluorodecyltrichlorosilane (FDTS) (CF3(CF2)7(CH2)2SiCl3), was proposed as a sacrificial layer for a lift-off process of a piezoelectric lead–zirconate–titanate (PZT) thin film on a Pt/Ti/SiO2/Si substrate. A FDTS fine pattern was firstly vapour deposited on a Pt/Ti/SiO2/Si substrate by a lift-off process, and then the PZT precursor was spin-coated on the Pt/Ti/SiO2/Si substrate, post-baked so the solvent decomposed and evaporated and annealed for crystallisation. The experimental results demonstrated that the super-hydrophobic FDTS with a contact angle of >120° is effective in preventing PZT crystallisation because of its thermal stability during PZT post-baking, and its barrier-effects between the spin-coated PZT precursor and the Pt/Ti substrate. After removing the FDTS and the PZT which is on top of the FDTS by a second lift-off process using ultrasonic agitation, a PZT fine pattern was successfully obtained on the Pt/Ti/SiO2/Si substrate with a thickness of 200–300 nm and feature size of a few tens of microns. In this Letter, the hydrophobic properties and surface morphology of different types of FDTS were studied and its barrier-effect on PZT crystallisation were analysed. The effects of PZT thickness in each spin-coating to lift-off the and PZT properties were investigated. The obtained PZT pattern was evaluated by an X-ray diffraction measurement.

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using inorganic nanoparticles has been reported as an organic matrix-free approach. However, the correlation of desorption/ionization (DI) efficiency with analyte chemical structures in SALDI-MS is not clear. In this study, we investigated the DI efficiency of 20 common amino acids and several peptides in SALDI-MS with Pt nanoparticles with thin projections on the surface (termed with Pt nanoflowers, Pt Nfs) on silicon substrates. The fluorocarbon-based hydrophobic perfluorodecyltrichlorosilane (FDTS)-Pt Nf substrates enabled the simultaneous analysis of all 20 common amino acids in negative-ion mode, whereas MALDI-MS was able to detect only two amino acids, proline and glutamic acid, from the same mixture in negative-ion mode. The SALDI-MS produced high ion yields for arginine and proline in positive-ion mode as well as for glutamic acid and aspartic acid in negative-ion mode. A linear correlation was found between the ion yield an...

Microporous membranes fabricated from hydrophobic polymers such as polyvinylidene fluoride (PVDF) have been widely used for membrane distillation (MD). However, hydrophobic MD membranes are prone to wetting by low surface tension substances, thereby limiting their use in treating challenging industrial wastewaters, such as shale gas produced water. In this study, we present a facile and scalable approach for the fabrication of omniphobic polyvinylidene fluoride (PVDF) membranes that repel both water and oil. Positive surface charge was imparted to an alkaline-treated PVDF membrane by aminosilane functionalization, which enabled irreversible binding of negatively charged silica nanoparticles (SiNPs) to the membrane through electrostatic attraction. The membrane with grafted SiNPs was then coated with fluoroalkylsilane (perfluorodecyltrichlorosilane) to lower the membrane surface energy. Results from contact angle measurements with mineral oil and surfactant solution demonstrated that overlaying SiNPs with ultralow surface energy significantly enhanced the wetting resistance of the membrane against low surface tension liquids. We also evaluated desalination performance of the modified membrane in direct contact membrane distillation with a synthetic wastewater containing surfactant (sodium dodecyl sulfate) and mineral oil, as well as with shale gas produced water. The omniphobic membrane exhibited a stable MD performance, demonstrating its potential application for desalination of challenging industrial wastewaters containing diverse low surface tension contaminants.

International audience; We present molecular dynamics simulations of self-assembled monolayers (SAMs) chemisorbed on an atomically flat amorphous silicon dioxide substrate. We model two prototypical SAM-forming alkylsilanes, octadecyltrichlorosilane (OTS) and 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS), that find widespread use in organic electronic applications. Crucially, our model does not rely on an explicit bonding between the alkylsilane and the substrate, thus allowing for the spontaneous organization of molecules into regular structures, which we studied as a function of coverage. By comparing the calculated tilt angle, film thickness, and lattice parameters with experiments, we conclude that the simulated morphologies are quantitatively consistent with the experimental evidence, demonstrating the accuracy of the simulation methodology. We take advantage of the atomistic resolution of the calculations for carrying out a detailed one-to-one comparison between the structure and the electronic properties of the two SAMs. In particular, we find that OTS molecules show a coverage-dependent tilt, while FDTS molecules are always vertically oriented, regardless of the coverage. More importantly for organic electronic applications, we observe that OTS SAMs do not alter the electrostatic potential of silica, while FDTS SAMs induce a negative voltage shift which increases with coverage and saturates at about -2 V

Perfluorodecyltrichlorosilane-based poly(dimethylsiloxane)-ZnO (FDTS-based PDMS-ZnO) nanocomposite coating with anti-corrosion and anti-fouling capabilities has been prepared using a one-step fabrication technique. XPS analysis and contact angle measurements showed the fluorine content to increase, while the hydrophobicity of the coatings decreased with addition of FDTS. XRD analysis revealed existence of ZnO nanoparticles of dimensions ranging from 11.45 to 93.01nm on the surface of coatings, with the mean particle size decreasing with FDTS addition, and was confirmed by SEM and TEM observations. Interestingly, the anti-corrosion performance and mechanical properties of the coatings increased remarkably on addition of FDTS. Indeed, the observed low adhesion strength, surface energies and the outstanding anti-corrosive properties imply that the obtained coating would be useful in anti-fouling applications.

We have characterized perfluorodecyltrichlorosilane (FDTS) molecular coating of aluminum molds for polymer replication via injection molding (IM). X-ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energies and roughness data have been collected. Samples have been characterized immediately after coating, after more than 500 IM cycles to test durability, and after 7 months to test temporal stability. The coating was deposited in an affordable process, involving near room temperature gas phase reactions. XPS shows detectable fluorine presence on both freshly coated samples as well as on post-IM samples with estimated 30 at.% on freshly coated and 28 at.% on post-IM samples with more than 500 IM cycles with polystyrene (PS) and ABS polymer.

Polycrystalline cobalt films 100 nm thick were thermally evaporated on oxidized Si(100) substrates. Then 1H, 1H, 2H, 2H perfluorodecyltrichlorosilane (FDTS) films of various thicknesses, in the range of about 2 nm to 30 nm, were grown on cobalt surfaces by vapor phase deposition (VPD). The cobalt films modified by FDTS were investigated using magnetic force microscopy (MFM) and atomic force microscopy (AFM). MFM observation showed that the magnetic structure of the cobalt films modified by FDTS is composed of domains with a considerable component of magnetization perpendicular to the film surface. This in turn indicates that the cobalt films on oxidized Si(100) substrates crystallize in the hexagonal close-packed (HCP) phase and exhibit a texture with the hexagonal axis perpendicular to the film surface. The magnetic domains formed a maze structure. The domain width increased from typically 80–120 nm to 400–500 nm with increasing the thickness of FDTS films from about 2 nm to 30 nm. AFM imaging of the surfaces of FDTS films revealed the presence of an agglomerate morphology. The agglomerates varied in size from typically 30–70 nm to 150–300 nm as the film thickness was increased from about 2 nm to 30 nm.

We report a new and facile method for synthesizing 3D platinum nanoflowers (Pt Nfs) on a scratched silicon substrate by electroless galvanic displacement and discuss the applications of the Pt Nfs in surface-assisted laser desorption/ionization-mass spectrometry (SALDI-MS). Surface scratching of n-type silicon is essential to induce Pt Nf growth on a silicon substrate (to obtain a Pt Nf silicon hybrid plate) by the galvanic displacement reaction. The Pt Nf silicon hybrid plate showed excellent SALDI activity in terms of the efficient generation of protonated molecular ions in the absence of a citrate buffer. We propose that the acidity of the Si-OH moieties on silicon increases because of the electron-withdrawing nature of the Pt Nfs; hence, proton transfer from the Si-OH groups to the analyte molecules is enhanced, and finally, thermal desorption of the analyte ions from the surface occurs. Signal enhancement was observed for protonated molecular ions produced from a titania nanotube array (TNA) substrate on which Pt nanoparticles had been photochemically deposited. Moreover, surface modification of the Pt Nf silicon hybrid plate by perfluorodecyltrichlorosilane (FDTS) (to obtain an FDTS-Pt Nf silicon hybrid plate) was found to facilitate soft SALDI of labile compounds. More interestingly, the FDTS-Pt Nf silicon hybrid plate acts 1) as a high-affinity substrate for phosphopeptides and 2) as a SALDI substrate. The feasibility of using the FDTS-Pt Nf silicon hybrid plate for SALDI-MS has been demonstrated by using a β-casein digest and various analytes, including small molecules, peptides, phosphopeptides, phospholipids, carbohydrates, and synthetic polymers. The hybridization of Pt Nfs with a scratched silicon substrate has been found to be important for achieving excellent SALDI activity.

In this paper, we present a study of tribological properties of fluorosilane monolayer on magnetic surface. The used fluorosilane was 1H, 1H, 2H, 2H perfluorodecyltrichlorosilane (FDTS), and the used magnetic material was a cobalt film. The effectiveness of modification of the cobalt surface by FDTS was monitored by the measurement of the wetting contact angle and the surface free energy. The increase of surface hydrophobicity was observed upon the modification by reducing the surface free energy and increasing the wetting contact angle. The nanotribological properties were characterized by means of adhesion, friction and wear, using atomic force microscopy (AFM). The cobalt surface modified by FDTS exhibits lower values of adhesion and the coefficient of friction in comparison with those for the unmodified surface. It was also found that FDTS effectively reduces wear of the system. We also investigated the magnetic structure of the cobalt film before and after modification by FDTS. The magnetic structure was composed of maze stripe domains magnetized perpendicular to the film surface, as revealed by magnetic force microscopy (MFM). The domain structure of the modified cobalt film was practically the same (in character and in size) as that observed for the bare cobalt film.

The paper reports on the fabrication of a localized surface plasmon resonance (LSPR) interface with nanocrystalline diamond (NCD) as overcoating. The LSPR interface is formed through thermal evaporation of a 4 nm gold film onto quartz substrates and postannealed at 800 °C. The resulting gold nanostructures (Au NSs) are further coated with nanocrystalline diamond (NCD) films produced by hot filament-assisted chemical vapor deposition (HFCVD) at 800 °C. The influence of the NCD film thickness on the wavelength at maximum absorption (λmax) was investigated by recording UV−vis transmission spectra in air. The experimentally obtained data were compared to the theoretically calculated one. The possibility to introduce chemical functions on the quartz/Au NSs/NCD interfaces was demonstrated by (i) photochemical oxidation of the NCD overcoating and subsequent reaction of the oxidized surface with perfluorodecyltrichlorosilane or (ii) chemical linking of the 4-nitrobenzene diazonium salt directly onto as-grown hydr...

The reliability and lifetime of cyclic contacting Si MEMS is limited by adhesion and their tribological performance. In this study, the tribological effects of adding a lubricant (tricresyl phosphate, TCP) to a bound self-assembled monolayer (perfluorodecyltrichlorosilane, PFTS) at different length scales were examined using a quartz crystal microbalance (QCM), an atomic force microscope (AFM), a reciprocating microtribometer, and a macroscopic reciprocating tribometer. The results showed that the addition of TCP to a PFTS layer increased the number of cycles possessing low friction and wear by at least a factor of four in the macroscopoic tribometer. Differences in friction response over the range of experimental scales were correlated to contact size and pressure. QCM measurements of TCP on PFTS showed a non-zero slip time, which suggests favorable tribological performance in larger length-scale regimes. This non-zero slip time also may indicate TCP mobility.

Hybrid dual-layer film was prepared on diamond-like carbon (DLC) surface by depositing mobile lubricant multiply-alkylated cyclopentane (MAC) on 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane self-assembled monolayers (FDTS-SAMs). The formation of comparatively uniform FDTS-SAMs on DLC surface was verified by static contact angle measurement, X-ray photoelectron spectrometer, and atomic force microscope (AFM). AFM result showed that a high density of regular but discrete nano-scale island-like liquid droplets of MAC were distributed on DLC surface with an interlayer of FDTS-SAMs to form hybrid AC-FDTS dual-layer film. The average diameter and height of MAC droplets on FDTS-SAMs are 30 nm and 35 Å, respectively, and the area covered by MAC droplets is ∼60 per cent. The tribological behaviour of the resulting hybrid film was evaluated on a pin-on-plate test rig using Zdol-2000 film and FDTS-SAMs as reference. The result showed that hybrid MAC-FDTS dual-layer film exhibited the best reducing-friction capability, load-carrying capacity, and durability compared with Zdol-2000 and FDTS-SAMs at applied loads of 50–250 mN. This may be attributed to the self-healing ability of the mobile MAC lubricant to diffuse and cover the damaged or defective areas of the substrates.

In nanoimprint lithography process, resist adhesion to the mold was usually self-assembled and a release agent on the mold surface to detach easily from the imprinted resist. In the paper, the commercially available silane, 1 H ,1 H ,2 H ,2 H -perfluorodecyltrichlorosilane (CF 3 –(CF 2 ) 7 –(CH 2 ) 2 –SiCl 3 or FDTS) was used to investigate the anti-adhesion for UV-nanoimprint lithography. A water contact angle as high as 113.11 was achieved by self-assembled monolayer (SAM) deposited on the quarter mold by vapor evaporation, which is desirable for a good anti-adhesion agent between the fused silica and the curing resist. The homogeneous monolayer was also evaluated by AFM and XPS. UV-NIL using FDTS-coated fused silica process good pattern transfer fidelity. It is shown that the FDTS is an excellent and promising release agent material for UV-nanoimprint lithography.

Micro∕nanoelectromechanical system devices and components often operate at high sliding velocities, and it requires the investigation of friction at high velocities. In this study, the velocity dependence of friction and the rest time effect on friction of hard diamondlike carbon films, soft perfluorodecyltrichlorosilane, and perfluoropolyether films were investigated up to 2×105μm∕s using an ultrahigh velocity stage and a high velocity stage. The velocity dependence of friction was found to vary with films and involve different mechanisms including adhesion due to solid-solid interaction, adhesion due to formation of meniscus bridges, atomic-scale stick slip, high velocity impact of the contacting asperities∕molecules, phase transformation∕tip jump, and viscoelastic shear. The increase in friction as a function of rest time was caused by continued growth and formation of water menisci bridges for the hydrophilic surfaces and continued deformation of soft films.

Providing a long period of sustained antibiotic release is one of the important challenges in the development of clinical shunts for long-term implantation. A cast-molding approach was used to load rifampicin into the silicone precursor before curing. Sustained in vitro release from rifampicin-loaded silicone for upwards of 110 days at a level of approximately 2-4 microg/cm2 per day was achieved. Quantitative comparisons of Staphylococcus epidermidis adhesion on untreated and rifampicin-loaded silicone surfaces were carried out to demonstrate the effect of rifampicin to discourage the bacterial adhesion. It was shown that the fresh 8.3% rifampicin-loaded silicone decreased bacterial adherence by 99.8%. Bacterial adherence on rifampicin-loaded silicone surfaces after 90 days release (eluted silicone) was decreased by 94.8%. A new approach was used to tune the initial burst effect and prolong long lasting release by introducing self-assembled perfluorodecyltrichlorosilane (FAS) and octadecyltrichlorosilane (OTS) layers. FAS layered structures can tune the burst effect and prolong the subsequent continuous release to achieve the long-term delivery. Significant decreases in initial burst effect (70.3% for multi-FAS layers and 39.7% for FAS monolayer) and enhanced long-term release (approx. 10 microg/cm2 per day for FAS monolayer for 110 days and approx. 15 microg/cm2 per day for multi-FAS layers for 60 days) were observed.

This paper investigates the influence of the applied load and sliding velocity on the microfrictional properties of native oxide-covered Si(100) and Si(100) coated with octadecyltrichlorosilane (OTS) and perfluorodecyltrichlorosilane (FDTS) self-assembled monolayers (SAMs) using a precision microtribometer. Microfriction was investigated as a function of the applied load and sliding velocity. As has been confirmed in earlier studies, in the microtribological regime, OTS and FDTS significantly reduce the friction force in comparison to the bare native oxide-covered (hydrophilic) silicon surface. The friction versus applied load curve of the substrate material as well as the SAMs-covered surfaces can be described by a model based on contact mechanics. For the native oxide surface, microfriction is reduced with increasing sliding speed. The friction force of the OTS- and FDTS-covered surfaces increases with load and is proportional to the natural logarithm of sliding speed. The increase with sliding velocity gets larger for higher normal loads. It can be shown that this increase is proportional to the contact area of the counter sample with the SAMs.

The effect of annealing (for temperatures up to 300 degC) on the antistiction performance of perfluorinated self-assembled monolayers (SAMs) is characterized using polycrystalline Si cantilever beam arrays. The monolayers 1H,1H,2H,2H, perfluorodecyltrichlorosilane (FDTS) and 1H,1H,2H,2H, perfluorodecyldimethylchlorosilane (FDDMCS) deposited from both liquid and vapor phase are investigated. It is observed that stiction decreases upon annealing for both monolayers and for both types of deposition. FDTS, however, displays greater temperature stability than FDDMCS regardless of the mode of deposition. The higher thermal resistance of the FDTS underscores the importance of monolayer crosslinking since unlike FDDMCS, FDTS forms a siloxane network on the surface. Further vacuum annealing and X-ray photoelectron spectroscopy experiments are performed to identify chemical changes in the monolayer during annealing. Incipient monolayer degradation is observed, with loss of the whole fluorinated monolayer chain. This process appears drastically different from the decomposition mechanism of hydrogenated alkylsiloxane monolayers such as octadecyltrichlorosilane (OTS)

Chemical and mechanical stability of FDTS (perfluorodecyltrichlorosilane) hydrophobic coatings was improved by using an oxide adhesion layer followed by an in-situ vapour deposition of the FDTS self-aligned monolayer. The use of silicon oxide base layer improves stability of the FDTS film and degradation of its hydrophobic properties resulting from a continuous immersion in water and other liquids. We ascribe the improved stability of the FDTS films grown on oxide to high density and uniformity of the surface hydroxyl groups required for FDTS attachment and the resulting high quality of the FDTS monolayer. This approach shows film property improvement over traditional substrates such as silicon and aluminium but may also be particularly useful in biochemistry and micro fluidics when films are deposited on substrates with lower density of the surface hydroxyl groups.

This paper presents an overview of the microtribological properties of silicon oxide, sapphire, and titanium carbide surfaces as well as a self-assembled monolayer with respect to their application in microsystems. Testing was performed with a reciprocating microtribometer with normal loads in the micronewton to millinewton range. Silicon and titanium carbide balls were used as counterbodies. For silicon oxide, sapphire and a perfluorodecyltrichlorosilane self-assembled monolayer (FDTS), the microfriction corresponds to the water contact angle when the smoother titanium carbide ball or the relatively rougher silicon ball was used as a counterbody. Microfriction measurements performed on tribopairs of the same material, but having different roughnesses, showed that the friction of the rougher tribopairs is lower than that of the smoother ones. Interestingly, in the microforce regime, reduction in friction was significant and almost as much as when hydrophobic self-assembled monolayers are applied on smooth surfaces. This investigation showed that comparative microtribological investigations between different material systems can be very challenging due to the fact that comparable roughness values on samples and countersamples are difficult to realize. Copyright © 2006 John Wiley & Sons, Ltd.

The best tribological properties can be obtained in a film that contains both bonded and mobile phases, and thus the ratio of the bonded phase to the mobile phase, the bonded ratio, is a critical factor for the lifetime of the mechanical components. In the present study, we deposited a mixed lubricant, which consists of a strongly bonded lubricant phase and a mobile lubricant phase, on a carbon overcoat. Islands of FDTS (perfluorodecyltrichlorosilane) SAM (self-assembled monolayer) were introduced as a strongly bonded lubricant phase and Fomblin Z03 lubricant as a mobile phase. The friction and durability properties of 2.5-in magnetic disks coated with 15 A thick mixed lubricants were investigated using a ball-on-disk tribotester and compared with disks coated with 15 A Zdol lubricants. Because the contact area of the ball increases with the bonded ratio, the friction coefficient of the disk coated with the mixed lubricant increases linearly with the bonded ratio over a range of about 25–100%. On the other hand, the friction coefficient of the disk coated with Zdol decreases with increasing bonded ratio. The mixed lubricant exhibits superior wear properties compared to Zdol. This may occur because the FDTS networks act as a barrier against the displacement of the mobile Z03 molecules, and the mobility of Z03 molecules is higher than that of Zdol molecules, which allows Z03 to replenish into the lubricant-depleted area at a higher rate.

The effect of substrate surface energy on transcrystalline growth at the interface of a semicrystalline polymer and its effect on interfacial adhesion were investigated for substrates treated with various silane coupling agents. A thin film of isotactic polypropylene (iPP) crystallized on a high surface energy substrate (treated with γ-(aminopropyl)triethoxysilane) was composed entirely of transcrystallites. On the other hand, when the iPP film was crystallized on a low surface energy substrate (treated with perfluorodecyltrichlorosilane), the interface was dominated by spherulites, and only a very thin transcrystalline region (thickness ∼1 μm) was observed. The substrate surface energy was found to exert a significant influence on the crystallinity, density of nuclei, crystal microstructure (e.g., lamellar thickness and crystal orientation), and thickness of the transcrystalline region near the interface. The adhesion energy measured by the asymmetric double cantilever beam (ADCB) test increased strongly...