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The purpose of this study was to see how silane treatment affected the tensile and impact strength of composites constructed from jute/kenaf/glass fibers with a nano-graphene filler and to investigate the impact of major treatment factors, such as silane concentration, immersion duration, and nano-filler, on composite characteristics. To conduct systematic trials and improve these variables, the Response Surface Methodology (RSM) with central composite designs was used. To precisely forecast the tensile and impact strength of the nano-composite following silane treatment, quadratic models were built. By changing the silane concentration, immersion period, and nano-filler, they discovered ideal conditions for increasing tensile strength. The best ranges for silane concentration and immersion duration were discovered to be 15 wt. % and 30 min, respectively. Given the conditions, the composite impact strength increased by 51% and its tensile strength improved by 22% as compared to the values achieved from RSM optimization. These results highlight the practical importance of silane treatment, especially in improving tensile and impact strength and strengthening the interfacial adhesive characteristics of organic fibers and polymer matrices. [ABSTRACT FROM AUTHOR]

We report on shear-stress relaxation of melts of poly(propyleneimine) (PPI) dendrimers of different generations (G2–G5). The aim of this study was to confirm our previous conclusion in Sheveleva et al. [Phys. Chem. Chem. Phys. 24, 13049–13056 (2022)] for carbosilane dendrimers that an impenetrable inner region leads to the manifestation of the crowded environment effect. The systems of PPI dendrimer melts are studied using atomistic molecular dynamics simulations. The time and frequency dependencies of the dynamic shear-stress modulus are investigated. The results are in good agreement with the available rheological experimental data for G2–G4 PPI. We have found that the crowded environment effect does not manifest itself in the mechanical relaxation of G4 PPI dendrimers in contrast to G4 carbosilane dendrimers. Despite their similar topology and close sizes, G4 PPI does not form an impenetrable core. The G5 PPI dendrimer has an impenetrable inner region, and the crowded environment effect is observed. As in carbosilane dendrimers, the maximal time of mechanical relaxation is increased due to the crowded environment effect. However, the opposite situation is for the rotational diffusion of the G5 PPI dendrimers. In contrast to carbosilane dendrimers, the rotational mobility of G5 PPI significantly slows down even taking into account the increase in the dendrimer size. The hydrogen bonding between PPI dendrimers affects the mechanical relaxation at high frequencies (short times) and enhances with growing G. [ABSTRACT FROM AUTHOR]

Since uniform dispersion and robust interfacial compatibility of nanofiller with epoxy resin are the most critical parameters to improve the corrosion protection property, a new effective anticorrosion nanofiller [polydopamine (PDA)@g-C3N4-CeO2] is designed by stacking PDA modified g-C3N4 and nano-CeO2 with the help of a silane coupling agent. The structure and morphology of PDA@g-C3N4-CeO2 are characterized by FTIR, XRD, XPS, SEM, and TEM. Furthermore, the PDA@g-C3N4-CeO2 nanofiller is loaded within waterborne epoxy coating (WEC) and the corrosion resistance of the prepared nanocomposite coating is studied. It can be inferred from the dispersion test that g-C3N4 modified by PDA and nano-CeO2 exhibits excellent dispersion and compatibility in de-ionized water. The Electrochemical impedance spectroscope (EIS) results indicate that nanocomposite coating with PDA@g-C3N4-CeO2 exhibits the best corrosion resistance, and its low-frequency impedance (Zf=0.01Hz) is 1.78 × 109 Ω cm2, which is two orders of magnitude higher than that of pure WEC (4.27 × 107 Ω cm2). In the salt spray test, PDA@g-C3N4-CeO2/WEC also showed excellent long-term corrosion resistance with few corrosion products even after 600 h, which was consistent with the results of the EIS test. In addition, PDA@g-C3N4-CeO2/WEC also reflects the most fantastic adhesion strength (14.22 MPa), which is improved by 45.40% than that of pure WEC (9.78 MPa). Generally, the excellent protection properties of PDA@g-C3N4-CeO2/WEC are attributed to the presence of PDA and KH-550 modified nano-CeO2 on the surface of g-C3N4, which increase the compatibility and surface interactions between nanofillers and epoxy resin. [ABSTRACT FROM AUTHOR]

A new hydroxy-silane coupling agent was synthesized from 3-butene-1-alcohol and mercaptopropyl-3-methoxysilane based on a click reaction between double bonds and sulfhydryl groups and was successfully used in the synthesis of silane-modified polyether (STPE). The effect of molecular weight of polypropylene glycol (PPG) on the properties of silane-modified polyether was studied. It was found that with the increase in PPG molecular weight, the initial thermal decomposition temperature and hardness of STPE elastomers decreased, but the molecular structure hardly changed. In addition, with the increase in molecular weight, the elongation at break of the elastomer will gradually increase, but the tensile strength of the elastomer does not change much. When the molecular weight reaches 20 000 g/mol, the resin with a viscosity of 1.6 × 105 mPa s can be obtained, and the elongation at break of the cured elastomer reaches 383.4% and the tensile strength is 0.25 MPa. After the STPE resin was prepared into a silane modified sealant, the tensile strength reached 1.31 MPa and the elongation at break reached 406.2%, which had the best mechanical properties among the prepared sealants. This shows that the sealant prepared from high molecular weight resin has stronger mechanical properties, which provides a new idea for the preparation of sealants. [ABSTRACT FROM AUTHOR]

Previous theoretical works suggested that superhydrophobicity could be enhanced through partial inhibition of the quantum vacuum modes at the surface of a broadband-absorber metamaterial that acts in the extreme ultraviolet frequency domain. This effect would then compete with the classical Cassie--Baxter interpretation of superhydrophobicity. In this article, we first theoretically establish the expected phenomenological features related to such a kind of "quantum" superhydrophobicity. Then, relying on this theoretical framework, we experimentally study patterned silicon surfaces on which organosilane molecules were grafted with all the coated surfaces having similar characteristic pattern sizes but different profiles. Some of these surfaces can indeed freeze quantum photon modes, while others cannot. While the latter ones allow hydrophobicity, only the former ones allow for superhydrophobicity. We believe that these results lay the groundwork for further complete assessment of superhydrophobicity induced by quantum fluctuations freezing. [ABSTRACT FROM AUTHOR]

The initial stages of particle formation are important in several industrial and environmental systems; however, the phenomenon is not completely understood due to the inability to measure cluster size distributions. A high resolution differential mobility analyzer with an electrometer was used to map out the early stages of Si particle formation from pyrolysis of SiH4 in a furnace aerosol reactor. We detected for the first time subnanometer stable clusters from silane pyrolysis, and the diameter was measured to be about 0.7 nm. This diameter is within the range of probable sizes that the reported families of critical silane clusters could have based on their actual molecular structure. The size distributions of negative clusters are also mapped out. In addition, gas chromatography mass spectrometry, and transmission electron microscopy characterizations of the clusters and primary particles are used to assess their mechanistic roles in aerosol dynamics of the initial stages of particle formation. [ABSTRACT FROM AUTHOR]

The feasibility of the compression of localized virtual orbitals is explored in the context of intramolecular long-range dispersion interactions. Singular value decomposition (SVD) of coupled cluster doubles amplitudes associated with the dispersion interactions is analyzed for a number of long-chain systems, including saturated and unsaturated hydrocarbons and a silane chain. Further decomposition of the most important amplitudes obtained from these SVDs allows for the analysis of the dispersion-specific virtual orbitals that are naturally localized. Consistent with previous work on intermolecular dispersion interactions in dimers, it is found that three important geminals arise and account for the majority of dispersion interactions at the long range, even in the many body intramolecular case. Furthermore, it is shown that as few as three localized virtual orbitals per occupied orbital can be enough to capture all pairwise long-range dispersion interactions within a molecule. [ABSTRACT FROM AUTHOR]

Medical devices are becoming more and more significant in our daily life. For implantable medical devices, good biocompatibility is required for further use in vivo. Thus, surface modification of medical devices is really important, which gives a wide application scene for a silane coupling agent. The silane coupling agent is able to form a durable bond between organic and inorganic materials. The dehydration process provides linking sites to achieve condensation of two hydroxyl groups. The forming covalent bond brings excellent mechanical properties among different surfaces. Indeed, the silane coupling agent is a popular component in surface modification. Metals, proteins, and hydrogels are using silane coupling agent to link parts commonly. The mild reaction environment also brings advantages for the spread of the silane coupling agent. In this review, we summarize two main methods of using the silane coupling agent. One is acting as a crosslinker mixed in the whole system, and the other is to provide a bridge between different surfaces. Moreover, we introduce their applications in biomedical devices. [ABSTRACT FROM AUTHOR]

Fundamental studies are needed to advance our understanding of selective adsorption in aqueous environments and develop more effective sorbents and filters for water treatment. Vapor-phase grafting of functional silanes is an effective method to prepare well-defined surfaces to study selective adsorption. In this investigation, we perform vapor phase grafting of five different silane compounds on aluminum oxide (Al2O3) surfaces prepared by atomic layer deposition. These silane compounds have the general formula L3Si–C3H6–X where the ligand, L, controls the reactivity with the hydroxylated Al2O3 surface and the functional moiety, X, dictates the surface properties of the grafted layer. We study the grafting process using in situ Fourier transform infrared spectroscopy and ex situ x-ray photoelectron spectroscopy measurements, and we characterize the surfaces using scanning electron microscopy, atomic force microscopy, and water contact angle measurements. We found that the structure and density of grafted aminosilanes are influenced by their chemical reactivity and steric constraints around the silicon atom as well as by the nature of the anchoring functional groups. Methyl substituted aminosilanes yielded more hydrophobic surfaces with a higher surface density at higher grafting temperatures. Thiol and nitrile terminated silanes were also studied and compared to the aminosilane terminated surfaces. Uniform monolayer coatings were observed for ethoxy-based silanes, but chlorosilanes exhibited nonuniform coatings as verified by atomic force microscopy measurements. [ABSTRACT FROM AUTHOR]

Small-molecule inhibitors have recently been introduced for passivation during area-selective deposition (ASD). Small silanes like (N,N-dimethylamino)trimethylsilane (DMATMS) selectively react with −OH sites on SiO2 to form a less reactive –OSi(CH3)3 terminated surface. The –OSi(CH3)3 surface termination can inhibit many atomic layer deposition (ALD) processes, including TiCl4/H2O ALD. However, the mechanisms by which ALD is inhibited and by which selectivity is eventually lost are not well understood. This study uses in situ Fourier-transform infrared spectroscopy to probe the adsorption of DMATMS on SiO2 and the subsequent reactions when the passivated surface is exposed to TiCl4/H2O ALD. The chemisorption of DMATMS on isolated –OH groups on SiO2 is shown to inhibit the reaction with TiCl4. Further, we find that starting with an inherently inhibiting H-terminated Si surface, DMATMS can also react with residual –OH groups and reduce the extent of nucleation. Finally, using Rutherford backscattering spectrometry, the effectiveness of DMATMS passivation on SiO2 and H-terminated Si is quantified during extended ALD cycle numbers. The insight into the mechanisms of passivation by DMATMS and passivation loss can enable the rational design of highly selective ASD processes by carefully matching compatible surfaces, passivating agents, and ALD precursors. [ABSTRACT FROM AUTHOR]

Area-selective atomic layer deposition (AS-ALD) is a coveted method for the fabrication of next-generation nano-electronic devices, as it can complement lithography and improve alignment through atomic scale control. Selective reactions of small molecule inhibitors (SMIs) can be used to deactivate growth on specific surface areas and as such enable AS-ALD. To investigate new applications of ASD, we need insight into the reactions of SMIs with a broad range of technology relevant materials. This paper investigates the reactions of aminosilane SMIs with a broad range of oxide surfaces and the impact on subsequent atomic layer deposition (ALD). We compare the reactions of two aminosilane SMIs, namely, dimethylamino-trimethylsilane (DMA-TMS) and hexamethyldisilazane (HMDS), with a hydroxylated SiO2 surface and the impact on subsequent ALD processes. The DMA-TMS reaction saturates faster than the HMDS reaction and forms a dense trimethylsilyl (TMS) layer with a higher TMS surface concentration. The higher TMS surface concentration yields better inhibition and higher selectivity during subsequent TiO2 ALD. We show that a wide range of surfaces, i.e., MgO, HfO2, ZrO2, Al2O3, TiO2 (TiN/TiOx), SiO2, SnO2, MoOx, and WO3 remain reactive after DMA-TMS exposure for conditions where SiO2 is passivated, indicating that DMA-TMS can enable AS-ALD on these surfaces with respect to SiO2. On these surfaces, DMA-TMS forms residual TMS and/or SiOxCyHz surface species that do not markedly inhibit ALD but may affect interface purity. Surfaces with lower, similar, and higher surface acidity than SiO2 all show less reactivity toward DMA-TMS, suggesting that surface acidity is not the only factor affecting the substrate-inhibitor interaction. Our study also compares a hybrid inorganic-organic SnOxCyHz and inorganic SnO2 material in view of their relevance as resist for extreme ultraviolet lithography. DMA-TMS can enable selective infiltration in SnOxCyHz, as opposed to selective deposition on SnO2, indicating tunable reactivity by bulk and surface composition. These insights into the reactivity of aminosilane SMIs may aid the design of new area-selective deposition processes, broaden the material space, and enable new applications. [ABSTRACT FROM AUTHOR]

Ion beam assisted thermal evaporation of the octa-silane polyhedral oligomeric silsesquioxane solid organic precursor was employed to deposit hybrid silicon oxide for the first time. This deposition process was primarily developed for ophthalmic lens applications as an alternative to the ion beam assisted chemical vapor deposition process. The main advantage of the proposed concept combining thermal evaporation and ion beam discharge is its transferability to industrial systems without significant scale-up investments. In the first part of this work, we performed a detailed diagnostic analysis (residual gas analysis and optical emission spectroscopy) of the effect of the experimental parameters on gas-phase processes. In the second part, we assessed and discussed the optical, chemical, structural, and mechanical properties of the deposited films. It has been found that the discharge current and oxygen gas ratio are the main parameters that adjust the coating properties and performance over a broad range. The adequately optimized combination of these two parameters allows one to fabricate flexible optical films with a low refractive index and a high elastic recovery. [ABSTRACT FROM AUTHOR]

A novel route to achieve an ideal plasma-enhanced atomic layer etching of silicon dioxide with self-limiting deposition and area-selective feature over silicon nitride is demonstrated in this work using a silane coupling agent and argon plasma. While monitoring the film thickness of silicon dioxide, self-limiting characteristics in both modification and etching steps are attained. Moreover, the dosing step revealed the selective formation of a modification layer on the oxide over the nitride film. In situ infrared spectroscopy results suggest the surface functionalization of the hydroxyl terminal groups of the oxide with the silane coupling agent to form the self-limiting modification layer at a relatively low substrate temperature. Compared to the previously reported fluorocarbon precursors, a higher etch yield for SiO2 was calculated, showing a promising option to meet the increasing demands in semiconductor production. [ABSTRACT FROM AUTHOR]

The material properties and bonding behavior of silane-based silicon oxide layers deposited by plasma-enhanced chemical vapor deposition were investigated. Fourier transform infrared spectroscopy was employed to determine the chemical composition of the silicon oxide films. The incorporation of hydroxyl (-OH) groups and moisture absorption demonstrates a strong correlation with the storage duration for both as-deposited and annealed silicon oxide films. It is observed that moisture absorption is prevalent in the silane-based silicon oxide film due to its porous nature. The incorporation of -OH groups and moisture absorption in the silicon oxide films increase with the storage time (even in clean-room environments) for both as-deposited and annealed silicon oxide films. Due to silanol condensation and silicon oxidation reactions that take place at the bonding interface and in the bulk silicon, hydrogen (a byproduct of these reactions) is released and diffused towards the bonding interface. The trapped hydrogen forms voids over time. Additionally, the absorbed moisture could evaporate during the post-bond annealing of the bonded wafer pair. As a consequence, defects, such as voids, form at the bonding interface. To address the problem, a thin silicon nitride capping film was deposited on the silicon oxide layer before bonding to serve as a diffusion barrier to prevent moisture absorption and incorporation of -OH groups from the ambient. This process results in defect-free bonded wafers. [ABSTRACT FROM AUTHOR]

In the manufacturing of integrated circuits (ICs), many deposition systems use solid, liquid, and gaseous precursors that can form potentially hazardous by-products in the exhaust lines. To assess the likelihood of an energetic reaction taking place, Gibbs free energy minimization was used to examine the reactions between chemical precursors, such as trimethylaluminum, trimethylindium, silane, and silane derivatives with H2O, O3, and Cl2. For the trimethyl-metal precursors, CH4 is a major by-product in both the O3 and H2O environments, and CH4, HCl, and CCl4 are possible products in the Cl2 environment. For silanes, a small H2O to silane ratio leads predominantly to the formation of H2 and siloxane while a large H2O to silane ratio leads primarily to the formation of H2 and more H2O. In addition to depositing reaction by-products, unreacted precursors may also deposit on the interior surfaces of the exhaust system, narrowing the cross-sectional area of the pipes. These narrowed regions can become temperature, pressure, and concentration hot spots where energetic reactions are more likely to occur. Results from this analysis may be helpful in designing a safer downstream exhaust system that minimizes the risk of energetic events. [ABSTRACT FROM AUTHOR]

A new nine-dimensional potential energy surface (PES) and dipole moment surface (DMS) for silane have been generated using high-level ab initio theory. The PES, CBS-F12HL, reproduces all four fundamental term values for 28SiH4 with sub-wavenumber accuracy, resulting in an overall root-mean-square error of 0.63 cm-1. The PES is based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit, and incorporates a range of higher-level additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, and scalar relativistic effects. Systematic errors in computed intra-band rotational energy levels are reduced by empirically refining the equilibrium geometry. The resultant Si-H bond length is in excellent agreement with previous experimental and theoretical values. Vibrational transition moments, absolute line intensities of the v3 band, and the infrared spectrum for 28SiH4 including states up to J = 20 and vibrational band origins up to 5000 cm.1 are calculated and compared with available experimental results. The DMS tends to marginally overestimate the strength of line intensities. Despite this, band shape and structure across the spectrum are well reproduced and show good agreement with experiment. We thus recommend the PES and DMS for future use. [ABSTRACT FROM AUTHOR]

In inverted perovskite solar cells, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Ag back interface is quite important because serious recombination occurs and H2O/O2 directly attacks this interface to induce device instability. Here, bi-functional dipole layers are applied at the interface aiming at improving the charge transport and device stability simultaneously. Silane with -CF3 end group anchored on the PCBM surface induces more effective dipole effect than that with (CH2)7-CH3 end functional silane, bending the interface energy level to promote electron transport and reduce recombination. The hydrophobic nature of -CF3 also enhances the durability of the device. This work highlights the back surface dipole management method to achieve efficient and stable perovskite solar cells. [ABSTRACT FROM AUTHOR]

We report on a new approach to transport samples for surface analysis safely from oxidation over long distances. The transport method is based on silane-doped inert gases, which are used as a transport medium. In this paper, we show that with the help of silane, highly purified inert gas atmospheres with oxygen contents of less than 10−15 mbar can be generated. In addition, we demonstrate that compared to commercially available inert gases, silane-doped inert gas atmospheres can be efficiently used to store and transport samples safely from oxidation. For this, surface sensitive measurements on highly reactive titanium samples, which passed the different stages of samples transport, were performed. The measurements revealed that no pronounced oxidation by the silane-doped atmosphere takes place. However, adsorption of silicon oxide from the atmosphere was observed. [ABSTRACT FROM AUTHOR]

The mechanism for growth initiation on the nongrowth surface during area-selective atomic layer deposition (ALD) processes is not well understood. In this study, we examine the ALD of ZrO2 on a SiO2 surface functionalized with alkylated-aminosilane inhibitors delivered from the vapor phase. ZrO2 films were deposited by ALD using tetrakis(ethylmethylamino)zirconium(IV) with H2O as the coreactant. In situ surface infrared spectroscopy shows that aminosilane inhibitors react with almost all the surface —SiOH groups on the SiO2 surface by forming Si—O—Si bonds. In situ four-wavelength ellipsometry shows that no ZrO2 growth occurs on the functionalized SiO2 during the first few ALD cycles, but growth eventually initiates after a few ALD cycles. We speculate that after repeated exposure of the functionalized SiO2 surface to Zr precursors, in the absence of surface —SiOH groups, growth initiates due to either reaction of the precursors with strained Si—O—Si bonds or through a strongly physisorbed state. These reaction pathways are usually not relevant in ALD reactions on the unprotected —SiOH-terminated SiO2 surface due to a higher activation energy barrier, but become relevant on the passivated surface as a result of repeated precursor exposure. Thus, this study highlights the importance of steric blocking of these higher activation energy barrier reaction pathways. [ABSTRACT FROM AUTHOR]

Low hydrogen content silicon oxycarbonitride (SiOCN) thin films were grown by plasma-enhanced chemical vapor deposition exploiting hydrogen dilution with silane/methane/nitrous oxide or tetramethylsilane/nitrous oxide precursors. The effects of deposition temperature were compared by investigating the compositional, optical, mechanical, and electrical properties of films grown at 100 °C, 250 °C, and 400 °C at thicknesses ranging from 50nm to 10 µm. The dielectric constant and high breakdown strength of the films remain relatively constant at between 4-5 and 6.8 ±0.2 MV cm-1 to 9.1 ±0.3 MV cm-1, respectively, despite the differences in deposition temperature. Other properties of the films include excellent transparency in the visible regime, high nanoindentation hardness (4 to 12 GPa), and relatively low measured stress on Si (-20 to -300MPa). Overall, the results of this work show that these SiOCN films can be used in a wide variety of applications, including as a dielectric within high voltage capacitors, transparent abrasion-resistant coatings for plastic windows, coatings on flexible substrates, a metal diffusion barrier for low-k dielectrics and polymer films, or within various microelectronic fabrication steps or systems. [ABSTRACT FROM AUTHOR]

Three-dimensional GaN columns recently have attracted a lot of attention as the potential basis for core-shell light emitting diodes for future solid state lighting. In this study, the fundamental insights into growth kinetics and mass transport mechanisms of N-polar GaN columns during selective area metal organic vapor phase epitaxy on patterned SiOx/sapphire templates are systematically investigated using various pitch of apertures, growth time, and silane flow. Species impingement fluxes on the top surface of columns Jtop and on their sidewall Jsw, as well as, the diffusion flux from the substrate Jsub contribute to the growth of the GaN columns. The vertical and lateral growth rates devoted by Jtop, Jsw and Jsub are estimated quantitatively. The diffusion length of species on the SiOx mask surface λsub as well as on the sidewall surfaces of the 3D columns λsw are determined. The influences of silane on the growth kinetics are discussed. A growth model is developed for this selective area metal organic vapor phase epitaxy processing. [ABSTRACT FROM AUTHOR]

Self-limiting character of the involved surface reactions is essential for highly uniform and conformal growth in atomic layer deposition (ALD). However, the poor conformal coverage (<75%) that is often reported with silicon nitride (SiNx) plasma enhanced ALD (PEALD) processes using metalorganic Si-precursors is confounding. In this article, we report our study of the SiNx PEALD process using the tris-dimethylamino silane (3DMAS) precursor and forming gas (5% H2–95% N2) reactant plasma. For the substrate temperature (Tsub) range of 50 °C ≤ Tsub ≤ 150 °C, growth per cycle (GPC) for SiNx deposition was found to approach saturation at 0.034 ± 0.001 nm/cycle though higher Tsub required longer 3DMAS exposures (tA) for saturation. However, for Tsub > 150 °C, SiNx GPC was seen to increase with tA, indicating nonself-limiting growth from potential chemical vapor deposition-like side reactions emerging at higher temperatures. The refractive index (n) of 2.097 ± 0.003 at 2 eV with an optical bandgap of ∼1.7 eV determined from in situ spectroscopic ellipsometry measurements, and peaks s1 and n1 with ΔBE = 295.42 eV in Si2p and N1s XPS spectra measured on the capped SiNx sample were found to agree with the optical constants and chemical characteristics reported for the silicon nitride material. SiNx films deposited at Tsub = 250 °C (nonself-limiting) were found to be more resistant to ambient oxidation as compared to SiNx PEALD films grown at Tsub = 100 °C. Although an entire 30 nm thick SiNx PEALD film was oxidized after an unavoidable long ambient exposure, a cross-sectional transmission electron microscope image showed a conformal coverage of 95%–98% in a 3D trench structure with an aspect ratio of 4.5. Furthermore, higher resistance to ambient oxidation in plasma treated of SiNx PEALD films demonstrates a potential of postgrowth treatments to improve desirable material properties without resorting to high-temperature processes. [ABSTRACT FROM AUTHOR]

The controlled modification of surface properties represents a pervasive requirement to be fulfilled when developing new technologies. In this paper, we propose an easy-to-implement protocol for the functionalization of glass with self-assembled monolayers (SAMs). The adaptivity of the synthesis route was demonstrated by the controlled anchoring of thiol, amino, glycidyloxy, and methacrylate groups onto the glass surface. The optimization of the synthetic pathway was mirrored by extremely smooth SAMs (approximately 150 pm roughness), layer thickness comparable to the theoretical molecule length, absence of silane islands along the surface, quasi-unitary degree of packing, and tailored wettability and charge. The functionalization kinetics of two model silanes, 3-mercapto- and 3-amino-propyltrimethoxysilane, was determined by cross-comparing x-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry data. Our SAMs with tailored physicochemical attributes will be implemented as supports for the crystallization of pharmaceuticals and biomolecules in upcoming studies. Here, the application to a small molecule drug model, namely aspirin, was discussed as a proof of concept. [ABSTRACT FROM AUTHOR]

Thin film coatings prepared from commercially available glycidoxypropyltrimethoxysilane (GPS) modified silica nanoparticles (SiNPs) (Bindzil® CC301 and Bindzil® CC302) have previously shown excellent antifouling performance against a broad range of microbes [Molino et al., "Hydration layer structure of biofouling-resistant nanoparticles," ACS Nano 12, 11610 (2018)]. In this work, single cell force spectroscopy (SCFS) was used to measure the biological interactions between Epicoccum nigrum fungal spores and the same silica nanoparticle-based surfaces used in the aforementioned study, including a: glass coverslip, unmodified SiNP coatings, and both low (Bindzil® CC301) and high density (CC302) GPS functionalized SiNP coatings as a function of NaCl concentration. From the SCFS curves, the spore adhesion to the surface was greatest on the glass coverslip (20–80 nN) followed by the unmodified SiNP (3–5 nN) across all salt concentrations. Upon approach to both surfaces, the spores showed a long-range attraction generally with a profile characteristic of biointeractions and likely those of the outer cell wall structures or biological constituents. The attractive force allowed the spores to initially adhere to the surface and was found to be linearly proportional to the spore adhesion. In comparison, both high and low density GPS-SINP significantly reduced the spore adhesion (0.5–0.9 nN). In addition, the spore adhesion on high density GPS-SiNP occurred in only 14%–27% of SCFS curves (40%–48% for low density GPS-SiNP) compared to 83%–97% for the unmodified SiNP, indicating that in most cases the GPS functionalization completely prevented spore adhesion. The GPS-SiNP surfaces conversely showed a long-range electrostatic repulsion at low 1mM NaCl that was replaced by short-range repulsion at the higher salt concentrations. From the findings, it is proposed that the attractive force is a critical step in initial adhesion processes of the spore. The effective antifouling properties of the GPS are attributed to the ability to negate the attractive forces, either through electrostatic repulsion in low salt conditions and primarily from short-range repulsion correlating to the previously reported combined steric-hydration effect of the GPS functionalization on SiNP coatings. [ABSTRACT FROM AUTHOR]

Silicon oxide (SiOx) has many applications, including as a low-refractive index material. Plasma enhanced chemical vapor deposition (PECVD) processes are facile, low temperature routes to produce thin SiOx layers. A route to decrease the refractive index of SiOx films is to increase the layer porosity although maintaining structural and optical stability remains challenging. Organic carbon-containing sacrificial layers have been shown to modify the growth and resulting structure of PECVD SiOx layers. In this work, we study the effect of adding methane (CH4) to the standard SiOx process gas mixture (silane and nitrous oxide) and varying deposition temperatures and microwave power in an industrial-scale, microwave PECVD reactor. Spectral ellipsometry was used to measure the optical properties of deposited layers, Fourier-transformed infrared (FTIR) spectroscopy to determine bonding and the layer porosity, and optical emission spectroscopy to characterize the plasma. We propose two regimes characterized by whether adding CH4 increases or decreases the refractive index and porosity of deposited layers compared to SiOx layers grown under standard conditions. However, the magnitude of the effect of adding CH4 was not large and would not find industrial application. Furthermore, the deposited layers' refractive indices increased over time, indicating that the effects of adding CH4 to the process gas mixture were not stable. To help explain our results and to provide guidance for future efforts to better control the refractive index of PECVD SiOx layers via carbon incorporation while maintaining layer stability, we propose possible growth pathways for our layers considering both plasma reactions and surface processes. [ABSTRACT FROM AUTHOR]

This work examines the antifouling effect of quaternary ammonium silane (QAS) grafted from coatings of silica nanoparticles (SiNPs), independently and in combination with a zwitterionic sulfobetaine (SB) silane. The binding of QAS to the SiNP coatings was monitored using quartz crystal microgravimetry with dissipation monitoring (QCM-D) under varied pH and solution concentrations. Adsorption of bovine serum albumin protein was reduced on QAS modified SiNP coatings prepared under alkaline conditions due to the proposed generation of a pseudozwitterionic interface, where the underlying SiNP surface presents an anionic charge at high pH. Significant reductions in protein binding were achieved at low functionalization concentrations and short modification times. Additionally, SiNP coatings modified with a combination of QAS and SB chemistries were investigated. Surface modifications were performed sequentially, varying silane concentration and order of addition, and monitored using QCM-D. Dual-functionalized surfaces presented enhanced resistance to protein adsorption compared to QAS or SB modified surfaces alone, even at low functionalization concentrations. The antiadhesive and antibacterial properties of functionalized surfaces were investigated by challenging the surfaces against the bacterium Escherichia coli. All dual-functionalized coatings showed equal or reduced bacterial adhesion compared to QAS and SB functionalizations alone, while coatings functionalized with high concentrations of combined chemistries reduced the adhesion of bacteria by up to 95% compared to control SiNP surfaces. [ABSTRACT FROM AUTHOR]

Thermodynamic properties of cellulose insulation paper are vital factors affecting the life of a transformer; in order to obtain cellulose insulation paper with better thermodynamic properties, three types of silane coupling agents—3-aminopropyltriethoxy silane (KH550), 3-glycidoxypropyltrimethoxy silane (KH560), and 3-methacryloyloxypropyltrimethoxy silane (KH570)—were grafted on the surface of nano-SiO2, and thermodynamic properties of cellulose modified with nano-SiO2 were explored. The molecular dynamics method was used to establish a composite model of nano-SiO2/cellulose. Also, different silane coupling agent grafted nano-SiO2/cellulose models were established to explore the effect of mechanical properties, interaction energy, free volume, and hydrogen bonds on thermodynamic properties. The results showed that KH550 was the best modification of the nano-SiO2/cellulose system among the three grafted silane coupling agents because KH550 grafted on the surface of nano-SiO2 formed more hydrogen bonds in the cellulose system. The interfacial bonding strength between the nano-SiO2 and the cellulose chains can effectively improve the thermal stability of the cellulose insulating paper. [ABSTRACT FROM AUTHOR]