Organofunctional Silanes Research Articles

Chankanai Zeolite Modified with Heteroatomic Derivatives of 3-Aminopropyltriethoxysilane as an Effective Sorbent for Ag(I), Co(II)

Bis-N,N-(3-triethoxysilylpropyl)thiosemicarbazide 3 was obtained by the condensation of 3-aminopropyltriethoxysilane 1 with thiosemicarbazide 2. Ethyl ether N-[3-(triethoxysilyl)propyl]-b-alanine 5 was obtained by the interaction of an equimolar amount of aminopropyltriethoxysilane 1 and ethyl acrylate 4 (aza-Michael reaction). Synthesized functional organosilanes 3 and 5 were successfully immobilized on the surface of natural zeolite Z (Chankanai deposit, Kazakhstan). Compounds and materials have been studied by NMR and IR Fourier spectroscopy and X-ray diffraction analysis. The elemental composition and morphology of modified zeolites Z3 and Z5 were studied using SEM-EDX analysis. The modification of zeolite by organosilanes 3 and 5 leads to changes in the surface structure of the material: with the enlargement of particles and agglomerates, the surface becomes more homogeneous and less porous. This indicates a high degree of zeolite coverage by the modifier layer. The study of the sorption characteristics of the initial Z and modified zeolites (Z3 and Z5) showed a high sorption capacity relative to Ag(I) and Co(II) (static sorption capacity, SSC = 35.85–23.92 mg/g), whereas the SSC values for Z were SSC = 20.63 and 16.64 mg/g. The adsorption of Ag(I) and Co(II) ions was studied in solutions prepared using Co(NO3)2·6H2O, AgNO3 and distilled water. The choice of the initial concentration of metal ions, as well as the pH of the solutions, corresponded to the composition of wastewater from real electroplating production. Zeolites Z3 and Z5 can be used in various sectors of industry, in ecology and for medical purposes as inexpensive and effective adsorbents (enterosorbents) of heavy and noble metals.

Direct synthesis of α-functionalized amides via heteroatom–hydrogen insertion reactions using amide-sulfoxonium ylides

α-Functionalized Si-, Ge-, B-, Se-, and S-amide moieties are present in many medicinally active molecules, but their synthesis remains challenging. Here, we demonstrate a high-throughput synthesis using amide-sulfoxonium ylides as carbene precursors in a Si–H, Ge–H, B–H, Se–H, and S–H insertion reactions to target a wide range of α-silyl, α-geryl, α-boryl, α-selenyl, and α-sulfur (hetero)amides. The process is featured as simple operation, mild conditions, broad substrate scope, high functional group compatibility, and excellent chemoselectivity. Both experimental and computational studies are conducted to explore the mechanisms underlying the formation of C–Si/Ge/B/Se/S bond. This research highlights the use of highly selective X–H insertion reactions with amide-sulfoxonium ylide-derived carbenes, paving the way for the preparation of diverse functional organosilane, organogermane, organoboron, organoselenium, and organosulfur compounds from accessible and bench-stable precursors.

Anti-corrosion Properties of Functionalized Organo-silane Coupling Agents for Galvanized Steel

Silane precursor selection is an important criterion for achieving great anticorrosive performance on steel substrates using sol-gel technology. A density functional theory (DFT) study was performed on functional and nonfunctional organosilane precursors. The global reactivity parameters, such as the global hardness (ƞ), dipole moment (μ), and number of electrons transferred (∆N) to the metal substrate, were calculated to identify suitable silane coupling agents. DFT studies revealed that precursors containing functional groups such as epoxy, amine, and mercapto offer better protection against corrosion to galvanized steel by providing stronger interfacial adhesion than precursors without functional moieties. The DFT-calculated adsorption energy (Eads) is more than 40.0kcal/mol for the adsorption of functional organosilanes onto the (ZnO)12 cluster. Evidence of chemical bond formation at the interface for functional organosilanes is found in the electron density overlap in the MOs. Natural charge analyses revealed clear charge transfer from the organosilane moiety to the (ZnO)12 cluster. The theoretical predictions were validated via experiments. Electrochemical studies demonstrated a protective efficiency of 92.5% for Ie with an impedance of 92.9kΩ·cm2. The presence of the respective functional groups and surface morphology were evaluated by FTIR and SEM. The order of corrosion inhibition of organosilanes was found to be MPTMS≈APTES>GPTMS>TEOS.

Predicted Corrosion Performance of Organofunctional Silane Coated Steel Reinforcement for Concrete Structures: An Overview

This article provides a comprehensive overview of the potential use of organofunctional silane coatings in the corrosion protection of concrete reinforcement in close relation to other commercially used coating technologies—i.e., epoxy coatings and bath hot-dip galvanizing coatings. The application technology of the steel surface is described in detail, and the corrosion performance and bond strength in concrete are compared. The paper also points out the possibility of improving the durability of epoxy coatings by the addition of silanes and, in the case of application to the surface of hot-dip galvanized steel, they can prevent corrosion of the coating by hydrogen evolution. The application potential of organofunctional silanes is also presented in the form of hydrophobic coatings on concrete surfaces or as corrosion inhibitors in simulated concrete pore solutions. The use of a suitable type of modified silane coating on the surface of carbon steel reinforcement can increase the corrosion performance and can also increase the bond strength in concrete. However, these facts need to be experimentally verified.

Thiol-isocyanate Click Reaction for Rapid and Efficient Generation of a Library of Organofunctional Silanes

Thiol-isocyanate Click Reaction for Rapid and Efficient Generation of a Library of Organofunctional Silanes

Anticorrosion and adhesion performance of a monolayer and double layer silane-epoxy coating systems applied on carbon steel

Carbon steel is one of the widely used metallic material, although its limited corrosion resistance. To improve its anti-corrosion performance, organic coatings such as epoxy have been an excellent option due to their barrier mechanism. Nevertheless, the elevated brittleness and porosity observed in this type of coating, coupled with the weak bonding interface between epoxy and carbon steel, significantly hampered their protective capabilities. The organofunctional silanes are candidates to be used as pre-treatment between epoxy coating and carbon steel interface because of their good corrosion resistance but as a limitation they can present small pores and microcracks.Therefore, the anticorrosive and mechanical properties of silane films can be adapted and further improved by strengthening the coatings through some modifications, such as the incorporation of green corrosion inhibitors into the film, reducing the access of aggressive species to the metal. In this context, the objective of this research is to evaluate the adhesion and anticorrosive properties of an epoxy-based organic coating pre-treated with a silane film obtained by tetraethoxysilane (TEOS) with γ-glycidoxypropyltrimethoxysilane (GPTMS) modified with the garlic peel powder as a corrosion inhibitor (Allium sativum L.). The investigation of the surface features as morphology and the corrosion resistance of the silane-epoxy coatings were studied by scanning electron microscope (SEM) and electrochemical characterization techniques, such as, electrochemical impedance spectroscopy (EIS), linear and potentiodynamic polarization. Also, the coating adherence was evaluated by pull-off tests. The results of the EIS showed that all samples coated with silane+ epoxy coating have better anticorrosion performance than the sample coated with just epoxy painting. Besides, SEM images showed that the silane film improved the cohesion between substrate and coating system, with the clear appearance of delamination in the system silane free. In general, the results of these different techniques indicate that the film modified with the natural inhibitor has improved anticorrosive properties compared to the film without silane or natural green inhibitors.

A Comprehensive Review on Processing, Development and Applications of Organofunctional Silanes and Silane-Based Hyperbranched Polymers.

Since the last decade, hyperbranched polymers (HBPs) have gained wider theoretical interest and practical applications in sensor technology due to their ease of synthesis, highly branched structure but dimensions within nanoscale, a larger number of modified terminal groups and lowering of viscosity in polymer blends even at higher HBP concentrations. Many researchers have reported the synthesis of HBPs using different organic-based core-shell moieties. Interestingly, silanes, as organic-inorganic hybrid modifiers of HBP, are of great interest as they resulted in a tremendous improvement in HBP properties like increasing thermal, mechanical and electrical properties compared to that of organic-only moieties. This review focuses on the research progress in organofunctional silanes, silane-based HBPs and their applications since the last decade. The effect of silane type, its bi-functional nature, its influence on the final HBP structure and the resultant properties are covered in detail. Methods to enhance the HBP properties and challenges that need to be overcome in the near future are also discussed.

Hemocompatible Functionalized Hydrogen Substituted Graphdiyne Based Highly Durable Biosensor for Liver Cancer Detection.

Present work focuses on the development of a highly durable biosensor for liver cancer (LC) biomarker (Annexin A2; ANXA2) detection. In this work, we have modified hydrogen substituted graphdiyne (HsGDY) using an organofunctional silane [3-(aminopropyl)triethoxysilane (APTES)], leveraging the opposite surface polarities on HsGDY and APTES to fabricate a highly hemocompatible functionalized nanomaterial matrix. The high hemocompatibility of APTES functionalized HsGDY (APTES/HsGDY) allows long-term stabilized immobilization of antibodies in their native state, hence increasing the durability of the biosensor. The biosensor was fabricated using electrophoretic deposition (EPD) of APTES/HsGDY onto an indium tin oxide (ITO)-coated glass substrate at 40% lower DC potential than nonfunctionalized HsGDY with successive immobilization of monoclonal antibodies of ANXA2 (anti-ANXA2) and bovine serum albumin (BSA). The synthesized nanomaterials and fabricated electrodes were investigated using a zetasizer and spectroscopic, microscopic, and electrochemical (cyclic voltammetry and differential pulse voltammetry) techniques. The developed immunosensor (BSA/anti-ANXA2/APTES/HsGDY/ITO) could detect ANXA2 in a linear detection range from 100 fg mL-1 to 100 ng mL-1 with a lower detection limit of 100 fg mL-1. The biosensor demonstrated excellent storage stability of 63 days along with high accuracy toward detection of ANXA2 in serum samples of LC patients as validated via enzyme-linked immunosorbent assay technique.

Effect of surfactant concentration in modifying solution on corrosion properties of the coatings based on vinyltrimethoxysilane (VTMS) and poly(3,4-ethylenedioxythiophene) (PEDOT)

This paper presents an analysis of the structure and physicochemical properties of coatings based on an organofunctional silane (VTMS), a conductive polymer (PEDOT), and a surfactant (polyoxyethylene glycol monolauryl ether BRIJ).The coatings were deposited on X20Cr13 stainless steel and glassy carbon specimens using sol-gel immersion. The obtained coatings were characterised in terms of topography, microstructure, roughness, adhesion to the steel substrate, thickness, and corrosion resistance. Corrosion tests were conducted in sulfate environments with pH = 2 without or with the addition of Cl- ions.The use of different surfactant concentrations in the modifying solution is intended to improve the deposition efficiency and increase the degree of dispersion of silane and conducting polymer.The tested coatings were found to slow down the corrosion of the steel substrate, thus effectively protecting it from this phenomenon. The use of a surfactant compound is intended to increase the degree of dispersion of silane and polymer in the modifying solution to improve deposition efficiency.Test carried out in corrosive media have shown that the coatings proposed in the above work, based on VTMS silane, PEDOT polymer and BRIJ surfactant, significantly increase the corrosion resistance of the tested materials, which confirms their effectiveness and possibility of application in various industries.The novelty of this paper is the use of silane (VTMS), polymer (PEDOT) and surfactant (BRIJ) as components of the anticorrosion coating.

A library of new organofunctional silanes obtained by thiol-(meth)acrylate Michael addition reaction.

A simple and efficient method for the synthesis of organofunctional silanes by the thiol-(meth)acrylate addition reaction is presented. At first, systematic studies were carried out to select an optimum initiator/catalyst of the addition reaction for the model reaction involving 3-mercaptopropyltrimethoxysilane (MPTMS) and hexyl acrylate. Photoinitiators (in the presence of UV light energy), thermal initiators (such as aza compound and peroxide) as well as catalysts (primary and tertiary amines, phosphines and Lewis acid) were studied. After selecting an effective catalytic system and optimizing the reaction conditions, reactions between the thiol group (i.e. 3-mercaptopropyltrimethoxysilane) and (meth)acrylates containing various functional groups were carried out. All derivatives obtained were characterized by 1H, 13C, 29Si NMR and FT-IR analysis. In reactions carried out at room temperature, in an air atmosphere and in the presence of dimethylphenylphosphine (DMPP) as a catalyst, quantitative conversions of both substrates were obtained within a few minutes. The library of organofunctional silanes was expanded by compounds (containing various functional groups, i.e. alkenyl, epoxy, amino, ether, alkyl, aralkyl, fluoroalkyl) which were obtained in the thiol-Michael addition of 3-mercaptopropyltrimethoxysilane to a group of organofunctional (meth)acrylic acid esters.

MnBr(CO)5: a commercially available highly active catalyst for olefin hydrosilylation under ambient air and green conditions

Commercially available MnBr(CO)5 was found to be a remarkable catalyst for olefin hydrosilylation reactions using a wide range of olefins and silanes. This system tolerates unpurified substrates and can be used in green solvents under ambient air.

Modifications of Textile Materials with Functional Silanes, Liquid Silicone Softeners, and Silicone Rubbers-A Review.

General information concerning different kinds of chemical additives used in the textile industry has been described in this paper. The properties and applications of organofunctional silanes and polysiloxanes (silicones) for chemical and physical modifications of textile materials have been reviewed, with a focus on silicone softeners, silane, and silicones-based superhydrophobic finishes and coatings on textiles composed of silicone elastomers and rubbers. The properties of textile materials modified with silanes and silicones and their practical and potential applications, mainly in the textile industry, have been discussed.

Chemistry and Applications of Organosilanes – An Overview

Organofunctional silanes are hybrid materials of silanes having attracted greater attention since the last decade owing to its versatile properties and wide range of applications. In this review, we have summarized the types of organosilanes (RnSiX4-n), their reactions, and applications. Organosilanes usually have two reactive groups, organofunctional groups and hydrolyzable alkoxy groups, which undergo hydrolysis and condensation. Silanols (Si-OH) and siloxane (Si-O-Si) structures are formed by hydrolysis and condensation reactions, respectively. In general, organosilanes acts as excellent binding agent due to its bridging capacity through (Si-O-Si) bond linkage with metal surfaces. From the extensive literature survey carried out, we understand that the silanes are synthesized without comprehending the reaction kinetics mechanism. In the past few decades, significant advances were witnessed in the development of various organofunctional silanes, which were used in a wide range of research areas based on its bifunctional characteristics.

Infrared Spectroscopy Studies of Aluminum Oxide and Metallic Aluminum Powders, Part II: Adsorption Reactions of Organofunctional Silanes

A gas phase, probe molecule doser was fabricated and connected to a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reaction chamber to study the reactions and stability of two organosilanes with the surfaces of metallic aluminum and boehmite powders in situ. Two metallic aluminum powder surfaces were studied, including an as-received, native oxide layer surface, and a laboratory prepared, boehmite-like surface. Neat boehmite powder was also used for reference and comparison to the laboratory prepared surface. We found that the metalloxane bond (Al-O-Si) was observed in the 1100–950 cm−1 region for all surfaces, which indicates chemisorption between the adsorbate and available surface hydroxyls. We were also able to draw correlations between the loss of surface –OH and the subsequent growth of –CH for additional confirmation of adsorbate retention. Hydrothermal stability was probed through intentional exposure to water after chlorotrimethyl silane dosing, which showed adsorbate loss through fractional decreases in intensity of the –CH stretches. These results provide clear evidence of metalloxane bonds formed on aluminum powder and insight into their stability, supporting the identification of these bonds on bulk scale silane treated powders.

Core‐shell Hierarchical Enzymatic Biosensor Based on Hyaluronic Acid Capped Copper Ferrite Nanoparticles for Determination of Endocrine‐disrupting Bisphenol A

AbstractA novel enzymatic electrochemical biosensor (mCuF/PANI‐nf/HA/Lacc/GCE) was designed for detection of bisphenol A (BPA). The copper ferrite nanoparticles was obtained by co‐precipitation and its surface was modified with ‐NH2 functional organosilane. Polyaniline nanofibers were also synthesized by cyclic voltammetry and characterized by FTIR, XRD, TGA, SEM and TEM, respectively. Then, it was crosslinked with hyaluronic acid as an immobilization matrix for Laccase to adhere to surface of the modified copper ferrites. Cyclic and differential pulse voltammetries were used to evaluate the electrochemical performances of the biosensor, which has a LOD value of 5.40 nM and a LOQ value of 16.20 nM in the 0.01–7.50 μM linear working range. The biosensor was successfully applied for determination of BPA in seawater, canned water and milk samples with recoveries ranging from 96.0 % and 100.7 %. In addition, accuracy of the voltammetric determination method in the real samples was carried out by HPLC and spike/recovery test. The layer‐by‐layer surface modification strategy of the designed mCuF/PANI‐nf/HA/Lacc/GCE biosensor opens a new perspective on both BPA determination and using biopolymer in the structure of enzymatic electrochemical biosensors.

Engineering Properties of New-Age (Nano) Modified Emulsion (NME) Stabilised Naturally Available Granular Road Pavement Materials Explained Using Basic Chemistry

Nanoscale organofunctional silanes have been developed, tested and successfully applied to protect stone buildings in Europe against climatic effects since the 1860s. The same nanotechnologies can also be used in pavement engineering to create strong chemical bonds between a stabilising agent and granular material. The attachment of the organofunctional silane to a material also changes the surface of the material to become hydrophobic, thereby considerably reducing future chemical weathering. These properties allow naturally available materials to be used in any pavement layer at a low risk. In the built environment, scientists soon determined that the successful use of an organo-silane depends on the type and condition of the stone to be treated. The same principles apply to the implementation of applicable nanotechnologies in pavement engineering. Understanding the basic chemistry, determining the properties of the stabilising agent and the organofunctional modifying agent and the chemical interaction with the primary and secondary minerals of the material are essential for the successful application of these technologies in pavement engineering. This paper explains some basic chemistry, which fundamentally influences engineering outputs that can be achieved using New-age (Nano) Modified Emulsions (NME) stabilising agents with naturally available granular materials in all road pavement layers below the surfacing.

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

In order to understand the evolution of the structure–property relationship between the crosslink density and mechanical properties of polyurethane-urea/sodium silicate (PU/SS) hybrid composites, a series of PU/SS composites with 2.5 wt% organofunctional silanes and pure PU/SS composites are investigated at different curing time. Mechanical properties, the fracture surface morphology, and thermo-mechanical properties of these PU/SS composites are characterized by electron omnipotence experiment machine, scanning electron microscope, and dynamic mechanical analysis (DMA), respectively. The mechanical test results show the strength and fracture toughness of the PU/SS composites first increase and then stabilize during cure, and the modification leads to PU/SS composites with significantly higher mechanical properties. Further, the morphology of fractured samples also reveals that the longer curing time and the modification of the PU/SS composites means a higher curing degree. Moreover, the increase in the crosslink density calculated from the DMA tests quantitatively confirmed the positive influence of the curing time and the modification in enhancing mechanical properties. In addition, it is also found that the mechanical properties of the PU/SS composites not only depend on the crosslink density but also on the well-dispersed hybrid PU/SS system.

Inhibitor efficiency of migratory corrosion inhibitors to reduce corrosion in reinforced concrete exposed to high chloride environment

Chloride-induced corrosion of steel reinforcement is the most important cause of premature failure of reinforced concrete structures. Corrosion inhibitors have proven to be an effective method to reduce corrosion rate in terms of application and cost-effectiveness. Various types of inhibitors are present such as organo-functional silanes, Amino-alcohol and Surfactant & amine salts-based inhibitors. The inhibitor efficiency of six major commercial migratory corrosion inhibitors, for reinforced concrete available in UK, was investigated using electrochemical study and permeability measurements to determine the most efficient inhibitor to protect steel in concrete with high chloride environment. It is showed that these compounds are effective inhibitors for reinforced concrete structures. Out of the tested inhibitors, organo-functional based inhibitors showed the best inhibitor efficiency and barrier properties.

Elucidating the Mechanism of Condensation-Mediated Degradation of Organofunctional Silane Self-Assembled Monolayer Coatings.

Dropwise condensation is favorable for numerous industrial and heat/mass transfer applications due to the enhanced heat transfer performance that results from efficient condensate removal. Organofunctional silane self-assembled monolayer (SAM) coatings are one of the most common ultrathin low surface energy materials used to promote dropwise condensation of water vapors because of their minimal thermal resistance and scalable synthesis process. These SAM coatings typically degrade (i.e., condensation transitions from the efficient dropwise mode to the inefficient filmwise mode) rapidly during water vapor condensation. More importantly, the condensation-mediated coating degradation/failure mechanism(s) remain unknown and/or unproven. In this work, we develop a mechanistic understanding of water vapor condensation-mediated organofunctional silane SAM coating degradation and validate our hypothesis through controlled coating synthesis procedures on silicon/silicon dioxide substrates. We further demonstrate that a pristine organofunctional silane SAM coating resulting from a water/moisture-free coating environment exhibits superior long-term robustness during water vapor condensation. Our molecular/nanoscale surface characterizations, pre- and post-condensation heat transfer testing, indicate that the presence of moisture in the coating environment leads to uncoated regions of the substrate that act as nucleation sites for coating degradation. By elucidating the reasons for formation of these degradation nuclei and demonstrating a method to suppress such defects, this study provides new insight into why low surface energy silane SAM coatings degrade during water vapor condensation. The proposed approach addresses a key bottleneck (i.e., coating failure) preventing the adoption of efficient dropwise condensation methods in industry, and it will facilitate enhanced phase-change heat transfer technologies in industrial applications.

Synergistic effect of ionic liquid and organo-functional silane on the preparation of silica based hybrid ionogels as solid-state electrolyte for Li-ion batteries

Having excellent safety and potentially high energy density, solid-state electrolytes can be used in large-scale energy storage applications instead of flammable and volatile organic solvent-based electrolytes. Aerogels are notable candidates for solid-state electrolytes due to their low density, high porosity, high specific surface area, stable thermal behavior, and ultralow dielectric constant. In this work, Li-doped silica ionogels were synthesized by the two-step sol-gel method by using trifunctional organosilane Methyltrimethoxysilane (MTMS), as silica co-precursor along with conventional precursor TEOS. In addition, 1,3-Butylmethylimidazolium bis(trifluorosulfonyl)imide (BMIMTFSI) was selected as an ionic liquid to provide ion mobility throughout the solid skeleton. The synthesized hybrid ionogels were characterized by FTIR, SEM, BET, and TGA analyzes. It was observed that the specific surface areas of the obtained ionogels varied between 685 and 725 m2/g. To examine the effect of Li+ ion concentration on ion conductivity, electrolyte solutions have prepared in different concentrations (0.5 ~ 2 M). The Li+ ion conductivity of the ionogel prepared with 2 M of Li+ ion solution (M-IGE-2) was determined as 4.06 × 10−4 S/cm by Potentiostatic EIS measurement and it possessed 3.3V of electrochemical stability.