Mixture Of Silane Research Articles

Rational design of Ag nanoparticle/polymer brush and its application in electroless deposition to fabricate adhesion-enhanced copper pattern for functional flexible electronics

BackgroundElectroless plating is a simple and promising method to fabricate surface-metallization material, low rupture work of plated coating and complex production process become important factors that restrict its progress. MethodsIn this study, silane (3-aminopropyltriethoxysilane (KH550) and γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560)) was incorporated in AgNO3 solution to rational preparing Ag nanoparticle/polymer brush (Ag/PB) catalytic solution and its application in electroless deposition to fabricate adhesion-enhanced copper pattern for functional flexible electronics. Significant findingsThe epoxy group in the KH560 can react with amino group in the KH550 through direct ring-opening reaction to form secondary amino group and hydroxyl, which could co-adsorb Ag nanoparticle by means of chelating structure, which exhibited superior Ag/PB interfacial characterization. As a result, Ag/PB was established on polyethylene terephthalate surface to achieve the modification of substrate with excellent adhesion and the catalysis of electroless copper plating when the PB is a mixture of AgNO3 and silane (75% KH560 and 25% KH550). Both maximum effective thickness and rupture work of Cu-plated coating were improved with the incremental rate of about 30% and 33%, respectively.

High-performance anode of lithium ion batteries with plasma-prepared silicon nanoparticles and a three-component binder

The crystalline silicon nanoparticles coated with an amorphous silicon layer was prepared by continuously pyrolysing the mixture of silane and hydrogen in a non-thermal arc plasma reactor. The hydrogen in the gas mixture effectively controls the thickness of the amorphous silicon layer and further improves the electrochemical performance of the silicon anode. The mechanism of the hydrogen was investigated by experiments. At the same time, a three-component polymer binder was concocted and introduced to tolerate the volume expansion of silicon effectively. Combining the silicon nanoparticles prepared at the optimal conditions with the novel polymer binder, the resulting silicon anode exhibits excellent electrochemical performance of 2120 mAh g−1 at 400 mA g−1 after 100 cycles.

Impact of water repellent agent concentration on the effect of hydrophobization on building materials

It is desirable to avoid or lessen moisture-related problems in building components exposed to wind-driven rain via correct material design and/or choice. In some cases however – e.g. for historic building facades – the only possibility is to modify the hygric properties of existing materials. Hydrophobization treatment is suggested as a possible protocol, but the proper concentration of the water repellent agent to achieve the expected effect is still open to discussion. This study proposes the novel concept of a material-dependent critical agent concentration: the lowest concentration that ensures hydrophobic effectiveness on a specific material. For validation, the hygric impact of hydrophobization treatment at different agent concentrations is studied. Specifically, a balanced mixture of silanes and siloxanes is used as the agent, and eight experiments are performed on ceramic brick, lime mortar and sintered glass. Results demonstrate the existence of a material-dependent agent concentration. Only when treated above it will the hygric properties be significantly modified. Moreover, hydrophobization impacts the capillarity of a material much more than its hygroscopicity, due to the difficulty for the large molecules of water repellent agents to penetrate into fine pores. The bulk density, open porosity and pore size distribution are typically only minimally influenced.

Hydrophilic/Hydrophobic Silane Grafting on TiO2 Nanoparticles: Photocatalytic Paint for Atmospheric Cleaning

In this study, anatase titania was utilized to prepare a durable photocatalytic paint with substantially enhanced photoactivity towards NO oxidation. Consequently, to alleviate the choking effect of photocatalytic paint and incorporate self-cleaning properties, the parent anatase titania was modified with Al(OH)3 and a number of organosilane (tetraethyl orthosilicate, propyltrimethoxysilane, triethoxy(octadecyl)silane, and trimethylchlorosilane) coatings. A facile hydrolysis approach in ethanol was employed to coat the parent titania. To facilitate uniform dispersion in photocatalytic paint and strong bonding with the prevailing organic matrix, it is necessary to avail both hydrophobic and hydrophilic regions on the titania surface. Therefore, during the preparation of modified titania, the weight proportion of the total weight of alkyl silane and trimethylchlorosilane was adjusted to a ratio of 1:1. As the parent titania has few hydrophilic portions on the surface, tetraethyl orthosilicate was coated with an organic silane having an extended alkyl group as a hydrophobic group and tetraethyl orthosilicate as a hydrophilic group. When these two silane mixtures are hydrolyzed simultaneously and coated on the surface of parent titania, a portion containing a large amount of tetraethyl orthosilicate becomes hydrophilic, and a part containing an alkyl silane becomes hydrophobic. The surface morphology and the modified titania’s optical attributes were assessed using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), UV-Vis diffuse reflectance spectroscopy (DRS), and electrochemical impedance spectroscopy (EIS) analysis. Based on the advanced characterizations, the NO removal mechanism of the modified titania is reported. The modified titania coated at 20 wt.% on the ceramic substrate was found to remove ~18% of NO under one h of UV irradiation. An extensive UV durability test was also carried out, whereby the coated surface with modified titania was exposed to 350 W/m2 of UV irradiance for 2 weeks. The results indicated that the coated surface appeared to preserve the self-cleaning property even after oil spraying. Hence, facile hydrolysis of multiple organosilane in ethanol could be a viable approach to design the coating on anatase titania for the fabrication of durable photoactive paint.

Plasma-Enhanced Chemical Vapor Deposition of Silicon Films at Low Pressure in GEC Reference Cell

A self-consistent fluid simulation of inductively coupled plasma-enhanced chemical vapour deposition (ICP-CVD) using silane, argon, and hydrogen mixture is presented. The model solves the continuity equations for charged species, the drift-diffusion equations to describe their transport and the electron energy balance equation, coupled with Maxwell’s and Poisson’s equations, using COMSOL Multiphysics software. In order to obtain a better comprehending of the discharge parameters, a discharge in a Gaseous Electronics Conference cell (GEC) reactor is simulated. In this study, the GEC reactor with five-turn inductive coils is driven at a radio frequency of 13.56 MHz in order to sustain the plasma discharge at low temperature for a mixture of SiH4/Ar/H2, with an intial gas pressure fixed at 20 mTorr. The simulations yield the profile of plasma components such as electron density and temperature as well as the electrical potential in the centre of the discharge during silicon films deposition. The effects of external settings, such as chamber pressure, applied power and hydrogen dilution, on the growth rate of the silicon films deposited by ICP-CVD are then investigated. It is shown that the increase of the applied power from 1000 to 3000 W and the gas pressure from 10 to 40 mTorr results in a moderate increase in the deposition rate of the silicon films, whereas the increase in the dilution of the hydrogen in the mixture produces its decrease.

Carbon-rich amorphous silicon carbide and silicon carbonitride films for silicon-based photoelectric devices and optical elements: Application from UV to mid-IR spectral range

In the work we demonstrated the possibility to apply amorphous non-stoichiometric silicon carbide (a-SixC1-x:H) and silicon carbonitride (a-SixC1-x-yNy:H) films for improvement of exploitation characteristics of silicon-based photoelectric devices and optical elements in very wide spectral range - from UV to mid-IR. The a-SixC1-x:H films possessing optical properties required for effective antireflection (AR) effects for silicon (refractive index (n) at λ = 632 nm from 1.86 to 1.98, optical bandgap (Eopt) from 2.7 to 3.1 eV, and extinction coefficient (k) is close to zero practically in all spectral range) were obtained by PE-CVD from methane, silane, hydrogen, and argon gas mixture. To deposit silicon carbonitride films some amount of nitrogen was added to the gas mixture. For the a-SixC1-x-yNy:H films the following optical parameters were obtained: n = 1.76–1.93, Eopt = 3.1–3.4 eV, k~0. It has been shown that the proposed films possess unique mechanical properties and ratio of the films hardness to their Young modulus is very high (H/E > 0.13). It is evidence of the films high wear resistance that is of great importance when the films are used for protection of silicon optical elements in IR spectral range. It is established that the films of both types are very suitable as excellent AR coatings for silicon in the spectral range of Si-based solar cell photosensitivity, telecommunication windows, and mid-IR. Deposition of even single layer AR film allowed us to reduce reflection losses significantly (reflection coefficient (R) at minimum of reflection becomes close to zero). As a result, efficiency of etched multicrystalline Si-based solar cell (SC) was significantly improved. Transmittance of Si-based optical elements with front and rear AR films reached practically 100% in the telecommunication windows spectral range.

Magnetoelectric Plasma Preparation of Silicon-Carbon Nanocomposite as Anode Material for Lithium Ion Batteries

A high-performance silicon-carbon nanocomposite facilely prepared by one-step magnetoelectric plasma pyrolysis of the mixture of methane, silane, and hydrogen is proposed for lithium-ion batteries. The ratio of silane, methane, and hydrogen was studied to optimize the properties of the composite. When the ratio of hydrogen/silane/methane is 1:1:3, the composite is composed of spherical Si nanoparticles that uniformly attach to the surface of the tremelliform carbon nanosheets framework, in which the tremelliform carbon nanosheets can effectively resist the volumetric change of the Si nanoparticles during the cycles and serve as electronic channels. The silicon-carbon nanocomposite exhibits a high reversible capacity (1007 mAh g−1 after 50 cycles), a low charge transfer resistance, and an excellent rate performance. In addition, the proposed process for synthesizing silicon-carbon nanocomposite without expensive materials or toxic reagents is an environmentally friendly and cost-effective method for mass production.

Maskless and contactless patterned silicon deposition using a localized PECVD process

We present a novel technique to perform contactless and mask-free patterned plasma enhanced chemical vapour deposition and etching. When a powered electrode with narrow slits is placed very close to the substrate, plasma is selectively ignited within the slits due to the hollow cathode effect, and so deposition or etching occurs only within an area smaller than the size of the slit. This technique is demonstrated through the deposition of hydrogenated amorphous silicon using a gas mixture of hydrogen, argon and silane. Slits as small as 1 mm generate a plasma, and for this width, the lines deposited are about 750 μm wide, homogenous over their length (60 mm), and are deposited at a rate of 50 nm min−1. The phenomenon is studied using 2D Particle In Cell (PIC) modelling with a simplified argon chemistry. The electron localization observed in the PIC modelling provides an explanation of why the deposition is narrower than the slit.

Different bonding agents effect on adhesive bond strength: lithium disilicate glass ceramic

Abstract Introduction The silanization of the ceramic surface prior to applying the adhesive and/or resinous materials plays an important role in bond strength. Nowadays, a new family of adhesive systems has been introduced into the market, aiming to simplify the technique of adhesive procedures during cementation. Objective To investigate the effectiveness of different bonding agents containing silane and primer on Lithium Disilicate Glass Ceramic (LD) surface by shear bond strength tests. Material and method 130 LD ceramic blocks were included in acrylic resin, polished and washed in ultrasound for 10 minutes. The specimens were divided into 2 groups according to surface treatment: Polished Surface (PS); Hydrofluoric Acid 9.5% - 20s (HF). Each group was divided into 5 subgroups (n = 13) according to bonding agent type: metallic primer containing MDP (ZPrimePlus, Bisco Inc); two traditional silanes (MonobondPlus, IvoclarVivadent / Porcelain Prime, Bisco Inc.); mixture of silane and resin (Kerr Silane, Kerr); mixture of silane and universal adhesive (Single-bond Universal, 3M Espe). The specimens were mounted in a standard device for shear testing (UltradentBonding Assembly), cemented with dual resin cement (RelyX UltimateTM, 3M Espe.) and photo-polymerized for 20s. The samples were tested after 24 hours and 3 months of storage in distilled water at ±36 °C. The data were analyzed by 3-Way Anova and Tukey's test (α = 5%). Result Shear bond strength (SBS) was significantly influenced by surface treatment, bonding agent used and storage (p <0.001). Conclusion Adequate adhesive bond strength to Lithium Disilicate Glass Ceramic can be obtained with traditional silanes, combined with HF acid pretreatment surface.

Characterization and evaluation of primer formulations for bonding silicone rubber to metal

The aim of this study was to explore the chemistry and adhesive properties of industrial primer formulations used for bonding silicone elastomers on AA6061 aluminum alloy. The composition of different primer formulations was determined using conventional chemical analyses. Adhesion strength was measured using 90° peel test. The formulation comprising partially condensed vinyltrimethoxysilane (VTMS) and tetrapropoxysilane (TPOS) and titanium tetrabutoxide (TTB) catalyst showed a strong adhesion to metal but a low adhesive strength of the primer-elastomer interface. 29Si NMR spectroscopy results have shown that exchange reactions of alkoxy groups of VTMS, TPOS and TTB has occurred in the formulation. Surprisingly, one formulation was free of silane and consisted of a one-component addition curing system comprising a SiH oligosiloxane, a vinyl-PDMS with a Pt catalyst and silica filler. This formulation enabled high cohesive strength of the primer and primer-elastomer interphase but it showed low adhesion to the metal. The more complex formulation containing a mixture of silanes (vinyltriethoxysilane, methyltriethoxysilane and tetraethoxysilane), a vinyl silicone gum, a hydroxy-terminated PDMS and silica filler resulted in the highest adhesive strength with 100 % cohesive failure in the elastomer. We found that the reinforcement effect of silica filler plays an important role in the promotion of adhesion.

Fabrication of a hydrophobic smart nanocontainer with pH-sensitive surface activation for controlled release

A hydrophobic pH sensitive nanocontainer was fabricated using smart surfaces covalently attached to a porous alumina support. The smart surface was synthesized using a mixture of aliphatic and aminated silanes and optimized to be hydrophobic at pH<7 and hydrophilic at pH<5. The hydrophobic nanocontainer thus synthesized was able to retain a cargo of the model molecule safranine at neutral pH. When pH decreased, safranine was liberated at a high rate due to the large pores of the alumina. It is expected that the nanocontainer here presented could constitute the basis of a cancer treatment as an effective drug delivery system in chemotherapy.

(Invited) Electrochemically Induced Phase Separation in Ionic Liquid Mixtures

Liquid-liquid phase separation is mainly dependent on temperature and composition. Electric fields have also been shown to influence demixing of binary liquid mixtures. However, a puzzling behavior that remains elusive is the electric field–induced phase separation in ion-containing solvents at low voltages, as predicted by Tsori and Leibler. Here, we report an experimental study of such a phenomenon in ionic liquid–silane mixtures, which not only results in phase separation at the electrode-electrolyte interface (EEI) but also is accompanied by deposition of porous structures of micrometer size on the electrode. This multiscale phenomenon at the EEI was found to be triggered by an electrochemically induced process. Using several analytical methods, we reveal the involved mechanism in which the formation of new Si–N bonds becomes unstable and eventually decomposes into the formation of silane-rich and silane-poor phases. The deposition of porous structures on the electrode surface is therefore a realization of the silane-rich phase. The finding of an electrochemically induced phase separation not only brings a paradigm shift in understanding the EEI in ionic liquids but also provides alternative strategies toward designing porous surfaces. Further examples like e.g. macroporous conducting polymers will be presented. reference: Abhishek Lahiri, Niklas Behrens, Giridhar Pulletikurthi, Arik Yochelis, Edwin Kroke, Tong Cui, Frank Endres, Science Advances 26 Oct 2018: Vol. 4, no. 10, eaau9663DOI: 10.1126/sciadv.aau9663

Structural analysis of hydrogenated nano-crystalline silicon suboxide (nc-SiOx:H, x < 1) thin films with SAXS for a potential application as phase change material

Hydrogenated nano-crystalline silicon suboxide (nc-SiOx:H; x < 1) is a two-phase material in which nanometer-sized silicon (nc-Si) region enclosed by hydrogenated amorphous silicon suboxide (a-SiOx:H) matrix. nc-SiOx:H thin films are produced by using highly hydrogen-diluted (dH ≥ 90%) plasma of silane and carbon-dioxide mixture, in a Plasma Enhanced Chemical Vapor Deposition (PECVD) system. The high concentration of the H-atoms in the plasma assist the silicon atoms on the growing film surface to crystallize. Small Angle X-Ray Scattering (SAXS) method was used to determine the nano-scale structures of nc-SiOx:H thin films, for varying hydrogen dilution ratios. The size, shape and the distribution of the nano-formations are found to depend strongly on the preparation conditions. From FTIR absorption and Raman scattering experiments, atomic oxygen and hydrogen contents and also the crystal ratio of the samples are evaluated. As results of nano-structural analyses, the morphologies, sizes and distributions of the nano-aggregations are found to be closely related to the crystallization of the films. From the SAXS results of the samples prepared at the hydrogen dilution ratio of 90%, the nano-aggregations are found to form in uniformly distributed core-shells. However, as the hydrogen dilution is increased to higher ratios to 95% and further to 99%, the nano-scaled fractals are deduced to form. The oxygen and hydrogen contents in nc-SiOx:H are strictly related to the crystal ratio of the samples. The crystal ratio is determined by the hydrogen dilution ratio during the deposition. The two-phase structure of nc-SiOx:H samples and the dependence on the hydrogen dilution ratio may suggest these materials are candidates for phase change materials. Depending on the deposition parameters, smaller nc-Si structures may be prepared which may have different (lower) electron densities required to melt the amorphous region and make the phase change possible due to explosive crystallization.

Process-dependent mechanical and optical properties of nanostructured silicon carbonitride thin films

Amorphous hydrogenated silicon carbonitride (a-SiCN:H) thin films were grown using electron cyclotron resonance chemical vapour deposition using a mixture of methane, nitrogen, and silane as precursors. The origin of the variation of macroscopic properties such as hardness (H), elastic modulus (E), photoluminescence (PL), and the optical band gap was investigated through their correlation with the microscopic features of a-SiCN:H thin films as a function of the process parameters, including the deposition temperature and methane gas flow rate. From a microstructural perspective, the thin films were investigated using x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, elastic recoil detection, transmission electron microscopy, and x-ray diffraction. It is verified that an increase of the substrate temperature resulted in the substitution of hydrogen atoms mainly by carbon atoms, causing the density of the silicon carbide-related structures to increase in the amorphous structure of the a-SiCN:H thin films. Hardness and elastic modulus were found to increase with the deposition temperature and decreased with an increase of the methane gas flow during the deposition, resulting in higher carbon content in the films. The observed changes are ascribed to the reduced density of the weak hydrogen terminated bonds and the variation of the relative bond density of Si–C to Si–N bonds. In addition, the thin films were depth profiled using a slow positron beam to investigate the role of vacancies. The observed increase of the positronium formation with increasing deposition temperature was found to correlate with the variation of PL, where an enhancement of the visible emission originating from carbon-related defects was observed. A set of optimized process parameters to fabricate a-SiCN:H thin films with improved visible emission and hardness properties is suggested.

Effect of Inert Micro- and Nanoparticles on the Parameters of Detonation Waves in Silane/Hydrogen–Air Mixtures

Physicomathematical modeling of interaction of detonation waves in silane/hydrogen composite mixtures with clouds of inert micro- and nanoparticles ranging from 10 nm to 100 µm is performed. The normalized detonation velocity is calculated as a function of the volume concentration of particles. It is found that the efficiency of detonation suppression increases only as the particle diameter decreases to 1 µm. The influence of the thermodynamic parameters of particles on the detonation suppression efficiency is identified. The concentration limits of detonation are determined. It is demonstrated that a certain equilibrium asymptotic level of the concentration limits of detonation is reached as the particle diameter decreases below 1 µm. An approximation of the concentration limits of detonation is obtained in the form of an analytical dependence of the limiting volume concentration of particles on their diameter and fuel concentration in a composite two-fuel mixture of silane, hydrogen, and air.

Microwave plasma-assisted silicon nanoparticles: cytotoxic, molecular, and numerical responses against cancer cells.

Silicon nanoparticles (SiNPs), which have a special place in material science due to their strong luminescent property and wide applicability in various physicochemical arenas, such as solar cells and LEDs, were synthesised by a microwave plasma-assisted process using an argon–silane mixture. Several characterization tools were applied to check the crystallinity (XRD) and morphological (FESEM, TEM, ∼20 ± 2 nm size) and topographical (AFM, ∼20 nm) details of the NPs. The high-purity SiNPs were applied on myoblast cancer cells to investigate the reactivity of the NPs at different doses (200, 1000 and 2000 ng mL−1) for different incubation periods (24 h, 48 h & 72 h). The MTT assay was utilized to determine the percentage of viable and non-viable cells, while the cell organization was observed via microscopy and CLSM. Additionally, the molecular responses (RT-PCR), such as apoptosis, were analyzed in presence of caspase 3 and 7, and the results showed an upregulation with SiNPs. To validate the obtained data, analytical studies were also performed for the SiNPs via statistical analysis and the most reliable data values were evaluated and acceptable as per the ICH guidelines.

Structure, optical property, and reaction process of Si quantum dots embedded in an amorphous silicon carbide matrix

Silicon quantum dots (QDs) embedded in an amorphous silicon carbide matrix were prepared using silane, methane, and hydrogen as reactive gases at a low substrate temperature by radio-frequency plasma enhanced chemical vapor deposition followed by thermal annealing at 1000 °C in a N2 atmosphere in the quartz furnace. The structure, optical properties, and reaction process of the synthesized Si QDs embedded in an amorphous silicon carbide matrix under different discharge powers are investigated. With the increase in the discharge power from 40 to 100 W, the experimental result measured by X-ray diffraction, Raman spectroscopy, UV-Visible spectroscopy, and field emission scanning electron microscopy reveals that the average size and the crystal volume fraction of Si QDs decrease from 4.4 to 3.4 nm and from 61.1% to 46.3%, respectively, while the optical bandgap and the deposition rate increase from 1.75 to 1.96 eV and from 15.5 to 16.5 nm/min, respectively. Moreover, the real-time diagnosis of plasma by optical emission spectroscopy (OES) is used to determine the chemical species and excitation temperature under the glow discharge of silane, methane, and hydrogen gas mixtures. Based on the OES measurement, the chemical reactions happening in the plasma and growth mechanism for the synthesis of Si QDs embedded in an amorphous silicon carbide matrix have been proposed. This work plays a significant role in preparation of the Si QDs embedded in an amorphous silicon carbide matrix for third-generation photovoltaic solar cells.

The evolution of PL properties of hydrogenated Si-rich silicon carbide/amorphous carbon nano-multilayer films grown by PECVD

Hydrogenated Si-rich silicon carbide (SixC1-x:H)/amorphous carbon (a-C:H) nano-multilayer films have been prepared by PECVD method with different silane mixture gas flow rates at 200 °C. The influence of the silane mixture gas flow rate on the chemical bonds, composition, microstructure, optical band gap and photoluminescence properties of the nano-multilayer films were studied by employing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV–vis) and photoluminescence spectroscopy, respectively. The FTIR and UV–vis spectra demonstrated that the incorporation of more carbon atoms into the SixC1-x:H networks is the main reason for the increase of optical band gap of the nano-multilayer films with increase of silane mixture gas flow rate. The Raman and HRTEM showed that there is no any nano-particles in the nano-multilayer films. The photoluminescence mechanisms of the nano-multilayer films was shown to be mainly contributed by band-to-band recombination of the Si-rich SixC1-x:H layers.

Investigation of hydrophobic coatings on cellulose-fiber substrates with in-situ polymerization of silane/siloxane mixtures

The purpose of this study was to investigate the interfacial interactions of SilRes BS290, a mixture of silanes and siloxanes, upon in-situ polymerization and curing over cellulose substrates (40 and 110 °C), and to further investigate the influence of these chemical interactions with hydrophobic development of the film. SilRes solutions (7 wt%) were prepared in n-heptane and roll-coated over pure cellulose substrates (Whatman). The bond development with time was monitored with FTIR, and was compared with surface hydrophobic development, monitored with contact angle analysis using deionized water droplets. It was found that the bond development was completed well before the onset of surface hydrophobicity in both the low and high temperature curing cases, with superhydrophobicity being observed for the high temperature preparations. Hydrophobic development tended to be influenced more strongly by surface topology resulting from the appearance of 300 nm-size polysiloxane beads on the fiber surface. Film porosity was also observed in some cases which additionally improved the hydrophobic outcome of the surface. While the hydrophobic behavior did not appear to coincide with the interfacial bond development of the in-situ polymerized film, damage to the surface hydrophobic layer via mechanical action decreased the hydrophobic performance in some cases. This was mainly due to a reduction in vibrational activity of the surface hydrophobic groups. High temperature curing maintained hydrophobic performance despite similar damage to chemical bonding, perhaps as a result of higher levels of covalent bonding to the substrate. Therefore, although the hydrophobic surface requires roughness and porosity to fully form, the chemical hydrophobicity created from polymerization also ultimately contributes to the overall hydrophobicity observed.

Modulating receptor-ligand binding in biorecognition by setting surface wettability.

Modulation of support wettability used for microarray format biosensing has led to an improvement of results. Hydrophobicity of glass chips was set by derivatizing with single vinyl organosilanes of different chain length and silane mixtures. Thiol-ene photochemical linking has been used as effective chemistry for covalent anchoring of thiolated probes. Lowest unspecific binding and highest signal intensity and SNR were obtained with large hydrocarbon chain (C22) silanes or a shorter one (C10) containing fluorine atoms. SNR resulting values are improved, reaching levels higher than 1500 in some cases, when using vinyl silanes modified with 1% C10 alkyl fluorinated one, because mild hydrophobicity was achieved (water contact angle ca. 110°) for all silanes, including the short C2 and C3, thus giving rise to smaller and better defined array spots. In addition, unspecific binding of reagents and targets was totally withdrawn. Hence, good-performing surfaces for biosensing applications can be built using appropriate organosilane reagent selection, including fluorinated ones. Graphical abstract ᅟ.