Silane Molecules Research Articles

Room-Temperature Synthesis of Germanium Oxide Nanofilaments and Their Potential Use as Luminescent Self-Cleaning Surfaces.

Germanium oxide nanofilaments (GNFs) have been synthesized under ambient conditions from the gas phase using germanium tetrachloride as a precursor. Non-crystalline GNFs synthesized by this procedure are 1-10 μm in length and 80-110 nm in diameter applying Droplet Assisted Growth and Shaping (DAGS) Chemistry. The relative humidity has been adjusted at various values in order to demonstrate the crucial role of humidity in the gas phase for the nanofilament synthesis. The novel GNFs show a strong luminescence emission in the ultra-violet and light blue region. In addition, a self-cleaning and superhydrophobic properties could be introduced in the luminescent GNF nanofilaments by simple treatment with silane molecules.

Effect of APTMS modification on multiwall carbon nanotube reinforced epoxy nanocomposites

In this present investigation, we have studied the effect of chemical functionalization, and mechanical dispersion of carbon nanotube (CNT) reinforced epoxy resin. The chemical function of the CNT has been done by silane treatment. Silane modification has been done first by acid treatment on ball-milled CNT followed by chemical treatment of amine-based silane. FTIR spectra exhibit that silane chemically interacts with the CNT and epoxy resin. Mechanical dispersion of CNT in the epoxy was performed in the planetary ball mill. Ball milled CNT shows some degree of exfoliation. Mechanical properties of ball-milled and silane modified CNT reinforced epoxy is characterized in terms of fracture toughness and tensile modulus. Silane-modified CNT/epoxy shows an increase of 38% and 42% compared to the neat resin for fracture toughness and tensile modulus values respectively. Increase in the mechanical properties for silane modified CNT/epoxy is due to the excellent adhesion between CNT-matrix as well as significant dispersion of CNT in the epoxy resin provided by silane molecule as observed from TEM images. AFM indentation on the nanocomposites exhibits the presence of CNT agglomerates through adhesion and corresponding modulus map at the nanoscale level. SEM images indicate an increase in surface roughness with CNT inclusion which relates to the existence of an extrinsic mechanism. Additionally, better adhesion between CNT and matrix due to silane modification indicate a higher Tg value of silane modified CNT/epoxy than ball milled CNT/epoxy.

The Oscillatory Adsorption of Organosilane Films on Aluminium Oxide: Film Morphology using Auger Electron Spectromicroscopy

The morphology of Propyltrimethoxysilane films during the oscillatory growth mechanism is shown using Auger Electron Spectromicroscopy. While the link between oligomerisation of silane molecules on the substrate and the oscillatory growth mechanism has been proposed previously, here for the first time we show the presence of silane film islands through Auger Electron Spectromicroscopy elemental mapping of the substrate. Monitoring the morphology of the film at key peaks and throughout along the oscillatory curve reveals the formation of a stable thin, homogenous film along with the presence of islands approximately 20 µm in diameter, whose numbers vary collectively during the adsorption/desorption mechanism. The measurable oscillations in silane substrate coverage has been directly linked to the repeated adsorption and desorption of silane islands on the aluminium substrate. The consequence of this mechanism is such that Propyltrimethoxysilane films behave most like a monolayer during the early stages of film growth, prior to siloxane oligomerisation.

Effect of Etchant on SOI Wafer Surface Roughness for APTES Silanization

Abstract In biosensor, organic molecule is used as coupling agent for silicon wafer to attach with DNA since DNA cannot be directly bonded with the silicon surface. There are several organic molecules that can self-assemble on silicon surface and modify their properties. Silane molecules such as (3-aminopropyl) triethoxysilane (APTES), (3-(aminopropyl) triethoxysilane (APTMS) and (3-mercaptopropyl) trimethoxysilane (MPTMS) have been commonly used as a primary step to covalently attach on silicon-on-insulator (SOI) wafer. Silanes were attached to the Si-O-Si bond on the surface on SOI wafer. In this research, the effect of APTES silanization on the surface roughness of SOI wafer was studied. Tetramethylammonium hydroxide (TMAH) was used to etch SOI wafer. Ranges of surface roughness of SOI wafer were obtained after adding some additives such as isopropyl alcohol (IPA) and triton X-100. Subsequently, gold nanoparticles (AuNPs) were attached on SOI wafer surface to confirm the existing of APTES. The surface roughness of SOI wafer was characterized in detail using atomic force microscope (AFM) and scanning electron microscope (SEM). The wettability of APTES solution on the etched SOI wafer surface was measured using goniometer. It was found that lower surface roughness of SOI wafer was observed after etched using ternary solutions that consisted of TMAH, Triton X-100 and IPA. It produced excellent hydrophilic effect of APTES solution then resulted in the highest weight percent of gold attached on the SOI wafer after the silanization process.

Особенности начальной стадии гетероэпитаксии слоев кремния на германии при их выращивании из гидридов кремния

AbstractData on the dependence of the growth rate of Si layers deposited onto Ge(111) by the hydride method on their thickness at the initial heteroepitaxy stage are reported. The effect of a Ge substrate within ten grown silicon single layers on the Si-film growth rate is demonstrated. Based on the data obtained, the kinetic coefficients responsible for the rate of the main physicochemical processes related to the interaction of hydride molecular beams with the growth surface are calculated. An analysis of the capture probability and rates of pyrolysis of the adsorbed Si(Ge) hydride molecules on the pure Ge(Si) surfaces reveals the dependence of their behavior on the growing-layer thickness. Comparison of the results obtained during Si-layer growth on Ge shows that the pure germanium surface has higher adsorption and catalytic abilities with respect to silane molecules than the pure Si surface. The unstrained pure Si surface has higher adsorption and catalytic characteristics with respect to Ge-hydride molecules.

The effect of amino-silane coupling agents having different molecular structures on the mechanical properties of basalt fiber-reinforced polyamide 6,6 composites

To improve the interfacial strength between basalt fibers (BFs) and PA6,6, amino-silane coupling agents were applied to BF-reinforced polyamide 6,6 composites. The effects of their molecular structures, especially the number of amino groups and the corresponding chain lengths, on the mechanical properties of basalt fiber-reinforced PA6,6 composites (BFRP) were then investigated. The results showed that even with the same type of silane coupling agent, the distinctive feature in its molecular structure is eventually displayed in the difference in the reinforcing mechanism to strengthen the interphase between BF and PA6,6, and consequently, its impact on the strength of the composites. The adhesive properties of BF to PA6,6 were promoted by the polar amino groups as well as the non-polar long CH2 chains of the silane coupling agents introduced to the BF surface. As the number of polar amino groups increased, the intermolecular hydrogen bonding with the CONH groups in PA6,6 increased, thus leading to enhanced interfacial adhesion between BF and PA6,6. The interfacial adhesion was also improved by the physical cross-linking formed from the chain entanglement between the silane molecules and PA6,6 as the number of non-polar long CH2 chains of the silane coupling agents increased. The tensile strength of their composites showed similar interfacial shear strength tendencies between BF and PA6,6 in the order of long-chain-, tri-, di-, and mono-amino-silane-treated BFRPs. Long-chain amino-silane was shown to be the most effective in strengthening the interphase between BF and PA6,6. This is because long-chain amino-silane induces strong chemical and physical bonding with PA6,6 as it has a large amount of amino groups in the terminate part and long CH2 chains in the spacer part.

Mixed-charge pseudo-zwitterionic mesoporous silica nanoparticles with low-fouling and reduced cell uptake properties

The design of drug delivery systems needs to consider biocompatibility and host body recognition for an adequate actuation. In this work, mesoporous silica nanoparticles (MSNs) surfaces were successfully modified with two silane molecules to provide mixed-charge brushes (-NH3⊕/-PO3⊝) and well evaluated in terms of surface properties, low-fouling capability and cell uptake in comparison to PEGylated MSNs. The modification process consists in the simultaneous direct-grafting of hydrolysable short chain amino (aminopropyl silanetriol, APST) and phosphonate-based (trihydroxy-silyl-propyl-methyl-phosphonate, THSPMP) silane molecules able to provide a pseudo-zwitterionic nature under physiological pH conditions. Results confirmed that both mixed-charge pseudo-zwitterionic MSNs (ZMSN) and PEG-MSN display a significant reduction of serum protein adhesion and macrophages uptake with respect to pristine MSNs. In the case of ZMSNs, this reduction is up to a 70–90% for protein adsorption and c.a. 60% for cellular uptake. This pseudo-zwitterionic modification has been focused on the aim of local treatment of bacterial infections through the synergistic effect between the inherent antimicrobial effect of mixed-charge system and the levofloxacin antibiotic release profile. These findings open promising future expectations for the effective treatment of bacterial infections through the use of mixed-charge pseudo-zwitterionic MSNs furtive to macrophages and with antimicrobial properties. Statement of SignificanceHerein a novel antimicrobial mixed-charge pseudo-zwitterionic MSNs based system with low-fouling and reduced cell uptake behavior has been developed. This chemical modification has been performed by the simultaneous grafting of short chain organosilanes, containing amino and phosphonate groups, respectively. This nanocarrier has been tested for local infection treatment through the synergy between the antimicrobial effect of mixed-charge brushes and the levofloxacin antibiotic release profile.

Quantum chemical studies on the inhibitive effect of silane derivatives

The correlation between the molecular structure and corrosion inhibition of silane derivatives including 3-mercaptopropyltrimethoxysilane (PropS-SH), dodecyltrimethoxysilane (DTMS), 3-aminopropyl(trimethoxy)silane (APS) and chloropropyl (trimethoxy)silane (CPTMS) was investigated by density functional calculations. It is found that the atoms O, C connected with Si atoms and terminal functional groups in silane molecules are active adsorption sites. The functional groups attached to the alkoxy carbon chain have an influence on the overall reactivity of the silane molecules. The PropS-SH molecules has the least energy gap and the highest reactivity, and therefore has the highest inhibition efficiency among the investigated inhibitors.

Remarkable Improvement in the Mechanical Properties of Epoxy Composites Achieved by a Small Amount of Modified Helical Carbon Nanotubes.

Helical carbon nanotubes (HCNTs) were functionalized to fabricate HCNT/epoxy composites. Acid oxidation and a silane coupling agent, glycidoxypropyltrimethoxysilane (KH560), were used to modify the HCNTs. Remarkably, the flexural strength and the flexural strain were enhanced by 72.0% and 325.0%, respectively, compared to pure epoxy after adding a small amount of the KH560 modified HCNTs (K-HCNTs). Simultaneously, the tensile strength and Young’s modulus of K-HCNTs/epoxy composites were 51.3% and 270.9% higher than those of pure epoxy. It is found that the presence of silane molecules improved the dispersion of HCNTs in epoxy and the interfacial interaction. Moreover, it has been found that the mechanically interlocking effect from the helical shape of HCNTs also contributes to the improved mechanical properties of epoxy composites, compared to their straight multi-walled carbon nanotube (MWCNT) counterparts. This work provides a low-cost and efficient approach to strengthen and toughen epoxy composites.

Morphological study of surface-modified urea–formaldehyde microcapsules using 3-aminopropyltriethoxy silane

In the current study, urea–formaldehyde (UF) microcapsules containing drying oils were prepared by in situ polymerization method. The surface of the prepared UF microcapsules was functionalized by using a silane-coupling agent. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), as well as atomic force microscopy observations showed that the surface roughness of the microcapsules has been promoted by the silane treating. Fourier transform infrared spectra and field-emission scanning electron microscopy coupled with energy-dispersive X-ray (EDX) analyses showed that the silane-coupling agent molecular binds strongly to the UF microcapsules surface. The particle size analyzer results show that agglomeration of the treated microcapsules was highly reduced. Thermogravimetric analysis indicated that this modification has improved thermal properties of the microcapsules. The SEM and TEM results indicated the surface roughness is increased after the functionalization treatment, and the silane molecules were attached to the surface of the UF microcapsules. According to EDXA, the weight percent of silicon was increased from 0.95 to 1.25 in the case of increasing the weight percent of the silane-coupling agent from 2 to 5 wt%. In fact, it was concluded that two major factors had influenced the UF microcapsules adhesion into the matrix, which were included as the interfacial bonds between the components and the surface roughness. The heat resistance of the microcapsules had been improved by silane-coupling agent functionalization.

Zwitterionic graphene oxide modified with two silane molecules for multiple applications

In this paper, zwitterionic graphene oxide (ZGO) was prepared with two silanes. It was evident that the silane molecules were grafted on GO surfaces by covalent bondings. ζ potential of ZGO varied from −29.0 mV to +28.5 mV when the pH of the aqueous solution was changed from 12 to 2. As a result, the ZGO can be dispersed in both anionic and cationic waterborne polymer matrix. Besides, ZGO can be used as two-dimensional surfactant in a wider range of pH values than GO. The multi-applications of ZGO were enabled by the unique pH-responsive charge-conversion properties and pH-insusceptible amphiphilicity.

Effect of silane functionalization on properties of polypropylene/clay nanocomposites

Abstract Polypropylene (PP)/clay nanocomposites were prepared by melt compounding with different grafted clay, such as montmorillonite, halloysite and sepiolite. These clays organically modified by grafting of two organosilanes namely 3-aminopropyltriethoxysilane (APTES) and vinyltrimethoxysilane (VTMS) were used as nanofillers for PP at different concentration (1–5 wt%). The physico-chemical properties of organosilane-modified clay-type were examined by various structural, thermal and morphological analysis routs. According to experimental data, all clays were successfully intercalaced using the silane molecules approved by the decline of the clay nano-particules size, modification of their chemical composition and the increase of their d-spacing. The efficiency of the silylation process as a good way to improve the matrix-fillers interaction was demonstrated by comparing the mechanical characteristics of the clays nanocomposites before and after grafting with organosilanes. Morphological and rheological properties of the PP/clay nanocomposites were also investigated in detail. In conclusion, it was found that the addition of the nano-organoclay allows improving the proprieties of silane grafted clays nanocomposites, which can endorse better interfacial adhesion between the organoclay and the polypropylene and their great spatial dispersion-distribution. The resulting PP/organosilane-grafted clay nanocomposites could be used by industry, or possible fields of application including automotive and construction industries.

Fabrication of ultrathin multilayered superomniphobic nanocoatings by liquid flame spray, atomic layer deposition, and silanization

Superomniphobic, i.e. liquid-repellent, surfaces have been an interesting area of research during recent years due to their various potential applications. However, producing such surfaces, especially on hard and resilient substrates like stainless steel, still remains challenging. We present a stepwise fabrication process of a multilayered nanocoating on a stainless steel substrate, consisting of a nanoparticle layer, a nanofilm, and a layer of silane molecules. Liquid flame spray was used to deposit a TiO2 nanoparticle layer as the bottom layer for producing a suitable surface structure. The interstitial Al2O3 nanofilm, fabricated by atomic layer deposition (ALD), stabilized the nanoparticle layer, and the topmost fluorosilane layer lowered the surface energy of the coating for enhanced omniphobicity. The coating was characterized with field emission scanning electron microscopy, focused ion beam scanning electron microscopy, x-ray photoelectron spectroscopy, contact angle (CA) and sliding angle (SA) measurements, and microscratch testing. The widely recognized requirements for superrepellency, i.e. CA > 150° and SA < 10°, were achieved for deioinized water, diiodomethane, and ethylene glycol. The mechanical stability of the coating could be varied by tuning the thickness of the ALD layer at the expense of repellency. To our knowledge, this is the thinnest superomniphobic coating reported so far, with the average thickness of about 70 nm.

On-off-on fluorescent nanosensor for Fe3+ detection and cancer/normal cell differentiation via silicon-doped carbon quantum dots

In this study, an on-off-on fluorescent nanosensor based on carbon quantum dots (or carbon dots, CDs) was successfully fabricated for Fe3+ detection and selective imaging of cancerous cells in vitro and in vivo. The multifunctional CDs were prepared by a one-pot solvothermal treatment of glycerol and a silane molecule (N-[3-(trimethoxysilyl)propyl]ethylenediamine, DAMO). The as-prepared CDs exhibited excellent fluorescence (FL) properties and favorable biocompatibility, and could realize wash-free cell imaging both in vitro (e.g., for bacterial and fungal cells) and in vivo (e.g., for zebrafish embryos). On the other hand, the fluorescence of CDs can respond to Fe3+ selectively and sensitively, with a very low detection limit of 16 nM. Besides, detection of Fe3+ in living cells and zebrafish was also successfully realized by the CDs. Moreover, it was found that glutathione (GSH) could enhance the fluorescence of the mixed solution of CDs and Fe3+ (CDs/Fe3+), and such a property could be utilized to efficiently distinguish cancerous cells from normal ones based on the difference in the content of GSH of the two types of cells. More importantly, GSH also realized the enhanced fluorescence signals of CDs/Fe3+ in tumor site in vivo after intravenous injection, indicating the potential of CDs/Fe3+ for imaging-guided precision cancer diagnosis.

Robust Operation of Mesoporous Antireflective Coatings under Variable Ambient Conditions.

Generating mesoporous films with adequate film thickness and refractive index is a common method to achieve amplitude and phase matching in low-cost interference-based antireflective coatings (ARCs). For high-surface-energy materials, pores on the 2-50 nm (i.e., on the subwavelength scale) are subject to capillary condensation by surrounding gas phase water molecules, which hampers their functioning. In this work, we examine the effect of relative humidity on mesoporous ARCs and present a simple method for the preparation of ARCs with robust operation under variable conditions. The materials route is based on the generation of well-defined porous aluminosilicate networks by block copolymer co-assembly with poly(isobutylene)- block-poly(ethylene oxide) and postsynthesis grafting of trichloro(octyl)silane molecules to the pore walls. The functionalized films exhibited a maximum transmittance value of 99.8%, with an average transmittance of 99.1% in the visible wavelength range from 400 to 700 nm. Crucially, the antireflection performance was maintained at high humidity values, with an average transmittance decrease of only 0.2% and maximum values maintained at 99.7%. This compared to maximum and average losses of 3.6 and 2.7%, respectively, for nonfunctionalized reference samples. The ARCs were shown to retain their optical properties within 50 humidity cycles, indicating long-term stability against fluctuating environmental conditions.

One-Step Synthesis of Ultrasmall and Ultrabright Organosilica Nanodots with 100% Photoluminescence Quantum Yield: Long-Term Lysosome Imaging in Living, Fixed, and Permeabilized Cells.

Water-dispersible nanomaterials with superbright photoluminescence (PL) emissions and narrow PL bandwidths are urgently desired for various imaging applications. Herein, for the first time, we prepared ultrasmall organosilica nanodots (OSiNDs) with an average size of ∼2.0 nm and ∼100% green-emitting PL quantum efficiency via a one-step hydrothermal treatment of two commercial reagents (a silane molecule and rose bengal). In particular, the structural reorganization and halide loss of rose bengal during the hydrothermal treatment contribute to the ultrahigh quantum yield and low phototoxicity of OSiNDs. Owing to their low pH-induced precipitation/aggregation property, the as-prepared OSiNDs can be used as excellent lysosomal trackers with many advantages: (1) They have superior lysosomal targeting ability with a Pearson's coefficient of 0.98; (2) The lysosomal monitoring time of OSiNDs is up to 48 h, which is much longer than those of commercial lysosomal trackers (<2 h); (3) They do not disturb the pH environment of lysosomes and can be used to visualize lysosomes in living, fixed, and permeabilized cells; (4) They exhibit intrinsic lysosomal tracking ability without the introduction of lysosome-targeting ligands (such as morpholine) and superior photostability; (5) The easy, cost-effective, and scalable synthetic method further ensures that these OSiNDs can be readily used as exceptional lysosomal trackers. We expect that the ultrasmall OSiNDs with superior fluorescence properties and easily modifiable surfaces could be applied as fluorescent nanoprobes, light-emitting diode phosphor, and anticounterfeiting material, which should be able to promote the preparation and application of silicon-containing nanomaterials.

Synthesis of Large‐Pore ECNU‐19 Material (12 × 8‐R) via Interlayer‐Expansion of HUS‐2 Lamellar Silicate

A large‐pore ECNU‐19 material with unique pore system consisting of 12‐ring (12R) pore channels intersected by 8R channels was post‐synthesized via interlayer‐expansion of HUS‐2 lamellar silicate with silylating agent of 1,3‐dimethyltetramethoxydisiloxane (DMTMDS). In consideration of the fact that the HUS‐2 precursor possessed a special structure with a malposition of the neighboring layers as well as silicon vacancies on layer surface, a “detemplating disassembly – intercalation reassembly – silylation” strategy was proposed to realize a successful interlayer‐expansion and structural amending. An acid treatment was firstly performed to remove a part of the structure‐directing agent molecules, which favored the following intercalation by bulk organic species. The intercalation not only rearranged the relative position of up‐down layers but also provided enough interlayer space for the insertion of dimeric silane molecules. Two –OH groups attached to one silicon atom of the silane molecule reacted with two close silanols on the up‐surface layer, while the other two –OH groups condensed with two silanols on the down‐surface layer, which then connected the two layers via ‐Si‐O‐Si‐ pillars and constructed new 12R pores along a axis and 8R pores along c axis, respectively.

Matrix-Infrared Spectra and Structures of HM-SiH3 (M = Ge, Sn, Pb, Sb, Bi, Te Atoms).

The reactions of Ge, Sn, Pb, Sb, Bi, and Te atoms with silane molecules were studied using matrix-isolation Fourier transform infrared spectroscopy and density functional theoretical (DFT) calculations. All metals generate the inserted complexes HM-SiH3, which were stabilized in an argon matrix, while H2M═SiH2 and H3M≡SiH were not observed. DFT and CCSD(T) calculations show the insertion complex HM-SiH3 is the most stable isomer with a near right angle H-M-Si moiety. However, silydene complexes H2M═SiH2 (M = C, Si) were calculated and identified as the most stable complexes with the lighter elements. The bonding difference is mainly due to relativistic effects, which is that for heavier metal atoms valence s and p orbitals have a lower tendency to form hybrid orbitals.

Converting detrimental HF in electrolytes into a highly fluorinated interphase on cathodes

A silane molecule with an unsaturated functionality effectively scavenges harmful hydrogen fluoride from the electrolyte and forms a complex, which experiences preferential oxidation and eventually delivers the fluorine species to the interphase that protects cathodes of high energy density batteries.

Silane functionalization of sodium montmorillonite nanoclay: The effect of dispersing media on intercalation and chemical grafting

Abstract This study investigated the effect of various dispersing media on the silane functionalization of sodium montmorillonite nanoclay (Na Mt) to evaluate each medium's effectiveness on the intercalation and chemical grafting of silane coupling agent. The amount of intercalation was estimated using the equation that was developed in our previous work based on thermogravimetric analysis. The results showed that the amount of silane intercalation was the greatest for water and glycerol media (≈1.582 mmol/g clay and ≈1.480 mmol/g clay, respectively), which was in agreement with the d001-values calculated by the XRD analysis (≈19.6 A and ≈14.4 A, respectively). 29Si NMR results showed a new T site in addition to Q peaks for all modified nanoclays in different dispersing media, indicating the occurrence of silane chemical grafting at the surface of the nanolayers. The A T 3 A Q 3 in NMR spectra was used to compare the amount of chemically grafted silane in different dispersing media, a new approach for Mt material. Hydrogen-bonding solvents (water, glycerol and ethanol), and polar solvents (DMF and THF) showed greater T3 peak intensities compared to other dispersing media, indicating higher amounts of chemical grafting of silane molecules. This observation was in agreement with the broadening of FTIR peak at 1130–1000 cm− 1, which is explained by the formation of extra Si O Si bonds; that is, in turn, due to silane chemical grafting at the surfaces of the nanolayers. The silane-nanofiller interactions were correlated with the Hansen solubility parameters of different dispersing media used for the modification. This research has potential to help design and improve the nanoclay modification processes, which are used in the fabrication of clay-polymer nanocomposites.