Phenyltrimethoxysilane Research Articles

Synthesis and Characterization of Copolymerized Vinyl/phenylsilsesquioxane Microspheres

Copolymerized vinyl/phenylsilsesquioxane microspheres were prepared by the sol-gel polymerization method from phenyltrimethoxysilane (PTMS) and vinyltrimethoxysilane (VTMS). The microsphere size was from 0.8 μm to 2.7 μm. Effects of the reaction parameters, such as NH4OH concentration, the ratio of oil to water (O/W) and monomer ratio on microsphere size, shape and distribution were investigated. The results indicate that the preferred preparation conditions are NH4OH concentration in 0.02 ∼ 1.28 wt%, ratio of O/W from 1/3 to 1/50 in hydrolytic co-condensation reaction. With the increasing of NH4OH concentration and PTMS/VTMS ratio and decreasing of O/W ratio, the microsphere size is decreased. Finally, FT-IR measurement was used to characterize the structure of the copolymerized vinyl/phenylsilsesquioxane microspheres.

Morphology and properties of polypropylene nanocomposites based on a silanized organoclay

A silanized organoclay (s-M 2(HT) 2) was prepared by reaction of trimethoxyphenyl silane with an organoclay with a M 2(HT) 2 surfactant structure. Nanocomposites were formed from polypropylene (PP) and a blend of PP and maleic anhydride-grafted polypropylene (PP- g-MA) and the M 2(HT) 2 and s-M 2(HT) 2 organoclays by melt processing to explore the extent of exfoliation and the mechanical properties. Wide angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) coupled with detailed particle analysis were used to determine the effect of the organoclay used and the PP- g-MA compatibilizer on exfoliation and mechanical, rheological, and thermal expansion properties. The PP/s-M 2(HT) 2 nanocomposites have higher particle densities than the PP/M 2(HT) 2 nanocomposites though the aspect ratio remains the same. Platelet dispersion is significantly improved by using PP- g-MA compatibilizer for both organoclays. The rheological properties and the relative modulus improve for the PP/s-M 2(HT) 2 nanocomposites but not to the same degree as either organoclay in a PP- g-MA compatibilized matrix. The thermal expansion properties, however, are not improved by using the s-M 2(HT) 2 organoclay. The s-M 2(HT) 2 organoclay is less prone to agglomeration during extrusion than the M 2(HT) 2 organoclay.

Fabrication of a novel nanocomposite based on sol–gel process for hollow fiber-solid phase microextraction of aflatoxins: B 1 and B 2, in cereals combined with high performane liquid chromatography–diode array detection

The new pre-concentration technique, hollow fiber-solid phase microextraction based on carbon nanotube reinforced sol–gel and liquid chromatography–photodiode array detection was applied to determination of aflatoxins B 1, B 2 (AFB 1, AFB 2) in rice, peanut and wheat samples. This research provides an overview of trends related to synthesis of solid phase microextraction (SPME) sorbnents that improves the assay of aflatoxins as the semi-polar compounds in several real samples. It mainly includes summary and a list of the results for a simple carbon nanotube reinforced sol–gel in-fiber device. This device was used for extraction, pre-concentration and determination of aflatoxins B1, B2 in real samples. In this technique carbon nanotube reinforced sol was prepared by the sol–gel method via the reaction of phenyl trimethoxysilane (PTMS) with a basic catalyst (tris hydroxymethyl aminomethan). The influences of microextraction parameters such as pH, ageing time, carbon nanotube contents, desorption conditions, desorption solvent and agitation speed were investigated. Optimal HPLC conditions were: C 18 reversed phase column for separation, water–acetonitril–methanol (35:10:55) as the mobile phase and maximum wavelength for detection was 370 nm. The method was evaluated statistically and under optimized conditions, the detection limits for the analytes were 0.074 and 0.061 ng/mL for B1 and B2 respectively. Limit of quantification for B1 and B2 was 0.1 ng/mL too ( n = 7). The precisions were in the range of 2.829–2.976% ( n = 3), and linear ranges were within 0.1 and 400 ng/mL. The method was successfully applied to the analysis of cereals (peanut, wheat, rice) with the relative recoveries from 47.43% to 106.83%.

The effect of chloride concentration and pH on pitting corrosion of AA7075 aluminum alloy coated with phenyltrimethoxysilane

The effect of chloride ion concentration and pH of solution on the corrosion behavior of aluminum alloy AA7075 coated with phenyltrimethoxysilane (PTMS) immersed in aqueous solutions of NaCl is reported. Potentiodynamic polarization, linear polarization, open circuit potential, and weight loss measurements were performed. The surface of samples was examined using SEM and optical microscopy. Elemental characterization of the coating by secondary ion mass spectrometry indicates an intermediate layer between coating and aluminum alloy surface. The corrosion behavior of the aluminum alloy AA7075 depends on chloride concentration and pH of solution. In acidic or neutral solutions, general and pitting corrosion occur simultaneously. On the contrary, exposure to alkaline solutions results in general corrosion only. Results further reveal that aluminum alloy AA7075 is susceptible to pitting corrosion in all chloride solutions with concentrations between 0.05 M and 2 M NaCl; an increase in the chloride concentration slightly shifted both the pitting and corrosion potentials to more active values. Linear polarization resistance measurements show a substantially improved corrosion resistance value in case of samples coated with PTMS as compared to uncoated samples in both neutral (pH = 7), acidic (pH = 0.85 and 3), and alkaline chloride solutions (pH = 10 and 12.85). The higher corrosion resistance of the aluminum alloy coated with PTMS can be attributed to the hydrophobic coating which acts as a barrier and prevents chloride ion penetration and subsequent reaction with the aluminum alloy.

Effect of silanes on the morphology, hydrophobicity, and dynamical mechanical properties of polyimide/silica hybrid membranes

AbstractPolyimide (PI)/silica hybrid membranes with high contact angles were prepared through the in situ sol–gel process. The precursor, poly(amic acid) with controlled block chain length, was synthesized using 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenone‐tetracarboxylic dianhydride (BTDA) and 3‐aminopropyl‐trimethoxysilane (APrTMOS) or 3‐aminopropyldimethylethoxysilane (APDiMOS). And then, phenyltrimethoxysilane (PTS) or tetramethoxysilane (TMOS) or methyltrimethoxysilane (MTrMOS) was respectively, added to the above polyamic acid and mixed thoroughly. Following curing reaction, the PI/silica hybrid membranes with different cross‐linkages, silica content, and hydrophobic properties were prepared. The effect on the formation of PI imide ring during imidization reaction is increased as the increase of silanes content and characterized by frequency shiftment and absorbance ratio of Fourier transform infrared (FTIR) measurements. All the hybrid membranes show high transparency though with high silica contents. The storage modulus, tan δ, and damping intensity by DMA measurements are all correlated with silane content or block chain length. And all these membranes with silane content possess high contact angle as compared to pure PI without any silanes added and the contact angles increase with increasing the silane content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A Comparison of Protease Active Sites and their Ability to Process Silicon-Based Substrates

Many enzymes have been identified that can participate in the hydrolysis of alkoxysilanes; each with a different degree of specificity. Our working hypothesis was that the nature of the active site of the enzyme (i.e., the compatibility of binding pockets with the substrate) could have a direct effect on the rate of catalysis. This communication reports our experiments on the relative rates of hydrolysis of a model alkoxysilane, phenyltrimethoxysilane (PTMS), by three proteases: trypsin, α-chymotrypsin, and pepsin. Trypsin which typically accepts amino acids bearing positively charged basic residues was not particularly proficient for the hydrolysis of PTMS. On the other hand, both α-chymotrypsin and pepsin, each of which contains a binding pocket, or two in the case of pepsin, suitable for accommodating aromatic residues, were more suitable for mediating hydrolysis. This report provides some preliminary data to support the hypothesis that the architecture of the enzyme active site is important in determining the proficiency with which an enzyme will process a given organosilicon substrate.

Manipulation of Work Function and Surface Free Energy of Tungsten Oxide Hole Injection Layer Modified with a Self-Assembled Monolayer

As a hole injection layer for organic devices, a tungsten oxide (WOx) thin film was vapor-deposited on an indium–tin oxide (ITO) substrate, on which a self-assembled monolayer (SAM) of either 3-aminopropyltrimethoxysilane (APS), phenyltrimethoxysilane (PTMS), or octadecyltrimethoxysilane (ODS) was prepared to modify the surface characteristics. The deposition of WOx substantially increased the ionization potential (Ip) of the substrate surface, which was effective in enhancing hole injection. The formation of SAM on WOx reduced Ip, but enabled the control of the surface free energy so as to modify the growth morphology of an organic film deposited on its surface. A hole-only device was prepared using a hole transport material of N,N '-diphenyl-N,N '-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD). In the space-charge-limited region, a high current was drawn by using an anode that has a high Ip. At low driving voltages, however, the current flow was considerably influenced by the surface free energy. It was found that the PTMS-SAM on WOx gives a satisfactory accommodation of both the work function and the surface energy.

Effect of additive ratio of mixed silane alkoxides on reactivity with TiO 2 nanoparticle surface and their stability in organic solvents

To improve stability of TiO 2 nanoparticles in various organic solvents, their surface was modified using a mixture of silane coupling agents having hydrophobic and hydrophilic groups. Decyltrimethoxysilane (DTMS) and phenyltrimethoxysilane (PTMS) were used as the former and 3-aminopropyltrimethoxysilane (APTMS), as the latter. First, effects of mixing ratios of silane coupling agents on reactivity with TiO 2 nanoparticle surfaces were investigated. The addition of APTMS increased the pH value of TiO 2 nanoparticle suspension due to the presence of the amine group and largely affected to the reacted amount of hydrophobic silanes. Next, relationships between the reacted amounts of silanes and their dispersion stability in various organic solvents were then investigated. Surface-modified TiO 2 nanoparticles were re-dispersible into low-polar solvents such as hexane, toluene, and THF when the reacted amount of hydrophobic silane was relatively high; however, TiO 2 nanoparticles were re-dispersible in highly polar solvents when the reacted amount of hydrophilic silanes increased. By controlling the amount of hydrophilic and hydrophobic silanes added, it is possible to effectively improve the dispersion stability of TiO 2 nanoparticles in various organic solvents.

Adsorption and interaction of organosilanes on TiO 2 nanoparticles

Organosilanes with different organic functional groups are precursors of corresponding organosilanol which can be attached to the surface of oxide nanoparticles by silyation. In this work, surface of commercial TiO 2 nanoparticles was modified by 3-aminopropyltrimethoxysilane (APS) and phenyltrimethoxysilane (PTMS) through an aqueous process. The amount of adsorbed organosilane was evaluated by energy dispersive X-ray spectroscopy and was found to be 3 times higher on PTMS treated sample than on APS treated sample. The orientation and bonding of the molecules on particle surface was analyzed using Fourier transform infrared spectroscopy and time-of-flight secondary ion mass spectrometry. The obtained data confirmed that bonding of organosilanols on particle surface was realized through Si–O–Ti bonds and organic functional groups were extended away from particle surface on both APS and PTMS modified particles. It was found that phenylsilanol molecules are cross-linked to each other through Si–O–Si bonds, while such bonds are very little to none between aminosilanol molecules. A model of adsorption is proposed to explain these observations.

Synthesis, Characterization and Ceramic Conversion Studies of Borosiloxane Oligomers from Phenyltrialkoxysilanes

Borosiloxane oligomers, which give ceramic residue in the range of 64–75% (at 900 °C in inert atmosphere), were synthesized through the condensation of boric acid with phenyltrimethoxysilane (PTMOS) and phenyltriethoxysilane in diglyme both in the presence and absence of hydrochloric acid as catalyst. The effect of concentration of the reactants and reaction time on the processability, yield and thermal stability of the product obtained was studied. The oligomers obtained are soluble in common organic solvents and were characterized by FT-IR and NMR spectroscopy, GPC and TGA. The ceramic conversion of one of the oligomers was carried out by heat treatment at 900, 1,500 and 1,650 °C in inert atmosphere. XRD studies reveal that the ceramic formed at 1,500 °C is amorphous and undergoes crystallization to β-SiC when heat treated at 1,650 °C.

Development of imprinted materials for the selective extraction of nitroaromatic explosives

Molecularly imprinted sorbents were synthesized and used as selective extraction sorbents for the analysis of nitroaromatic explosives. Their synthesis by radical polymerization using organic monomers and by sol–gel approach using organosilanes was considered to develop a selective sorbent. The sol–gel approach with phenyltrimethoxysilane (PTMS) as monomer and 2,4-dinitrotoluene (2,4-DNT) as template gave the most promising results. An optimized procedure adapted to the selective treatment of aqueous samples was then developed and applied to various target explosives. For the first time four nitroaromatic compounds were retained on the molecularly imprinted silica (MIS) with extraction recoveries between 29% and 81%, while only low recoveries were obtained on the non-imprinted sorbent, thus highlighting the high degree of selectivity. The MIS was then used for the clean-up of a sample containing motor oil spiked with 2,4-DNT and 2,4,6-trinitrotoluene (2,4,6-TNT). The results were compared with those obtained using a conventional sorbent (Oasis HLB). The cleanest chromatogram obtained using the MIS emphasized the high potential of the MIS as selective sorbent.

Effect of coupling agent on the thermal and dielectric properties of PTFE/Sm 2Si 2O 7 composites

The present study investigates the dielectric and thermal properties of PTFE/Sm 2Si 2O 7 composites. The composites were prepared by powder processing technique followed by hot pressing. The variation of the dielectric properties with filler content (0–0.5 V f ) was studied at 1 MHz and 9 GHz. The filler surface was chemically modified using phenyl trimethoxy silane (PTMS) as a coupling agent. The microstructural study using scanning electron microscopy (SEM) showed that the particles were well dispersed in the matrix when coupled with PTMS. The surface modification led to an improvement in the dielectric properties. The PTFE filled with 0.4 V f silane treated Sm 2Si 2O 7 composite showed a low dielectric loss of 0.0054 and slightly higher relative permittivity of 3.92 when compared with the untreated composite of the same composition. The experimental values of relative permittivities were compared with the theoretical predictions and the Effective Medium Theory was found to agree well even for higher content of silane treated filler. It was found that the addition of silane coupling agent is very effective in improving the thermal properties of the PTFE/Sm 2Si 2O 7 composites.

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

Organo-functionalized FDU-12 type silicas exhibiting large pore sizes and ordered mesoporous structures were synthesized at low reaction (15 °C) and high hydrothermal (160 °C) temperatures via the co-condensation of tetraethoxysilane (TEOS) with a suite of organosilanes, i.e., 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), vinyltrimethoxysilane (VTMS), and phenyltrimethoxysilane (PTMS), in the presence of structure directing micelles formed using the surfactant pluronic F127 and the pore enlarging reagent trimethylbenzene (TMB). Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) confirmed that all synthesized materials possessed a face-centered cubic mesostructure (space group Fm3̅m), while nitrogen sorption analyses showed that the synthesized materials had extra large pores with cavity sizes of up to 25.4 nm and entrance sizes of up to 10.8 nm. X-ray photoelectron spectroscopy (XPS) and 13C solid-state magic-angle spinning nuclear magnetic resonance (13C-MAS NMR) measurements verified the incorporation of the different organosilanes into the silica network and more importantly on the inner and outer surfaces of the materials. As-obtained mesoporous silicas were tested in protein immobilization studies using bovine serum albumin and the cellulose-hydrolyzing enzyme cellulase, which in itself is a mixture of three large enzymes. Enzyme immobilization efficiency, activity, and stability varied significantly with organic functionality due to size exclusion effects at pore entries, electrostatic and hydrophobic interactions between the organo-functionalized surfaces and the enzymes, and conformational changes of the enzymes which can occur on some of the material surfaces. As a result, phenyl (PTMS)- and thiol (MPTMS)-functionalized FDU-12 mesoporous silicas had a very low adsorption capacity of proteins because of their small pore sizes. Amino (APTES)-functionalized FDU-12 mesoporous silica showed the highest adsorption amount of proteins yet the lowest activity of immobilized cellulase. Cellulase immobilization on vinyl (VTMS)-functionalized FDU-12 mesoporous silica appeared to be the most promising approach, since it occurred with high efficiency, maintained enzyme activity, and provided temporal enzyme stability.

One-pot synthesis of organo-functionalized monodisperse silica particles in W/O microemulsion and the effect of functional groups on addition into polystyrene

The direct synthesis from TEOS and organosilanes is carried out in W/O microemulsion in order to prepare monodisperse functionalized silica nanoparticles. The well monodisperse particles are obtained successfully from a wide range of concentration of 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), phenyltrimethoxysilane (PTMS), vinyltriethoxysilane (VTES) and 3-cyanoethyltriethoxysilane (CETES) in the solution of TEOS and polyoxyethylene nonylphenol ether (NP-5). The particle size can be controlled without widening the distributions. On the other hand, the direct synthesis with these organosilanes and TEOS by conventional Stöber method using no surfactant provides colloidal solutions with DLS plots with wide or bimodal dispersions. NP-5 is removed by washing the colloids with DEGDEE and the decline of IR absorptions due to the benzene ring stretching is observed. The resultant colloidal powder is occluded into polystyrene by the polymerization of styrene monomer in the presence of these functionalized silica nanoparticles. The heat resistance of modified polystyrene is investigated by TG–DTA in dry air. The position of DTA peak due to combustion of the polymer is shifted to a higher temperature with the addition of silica nanoparticles. The considerably large shift is found in silica nanoparticles prepared with VTES and PTMS, whose difference is higher than that by the addition of simple silica nanoparticle with no functional groups.

Electrochemical codeposition of sol–gel films on stainless steel: controlling the chemical and physical coating properties of biomedical implants

The electrochemically assisted codeposition of sol-gel thin films on stainless steel is described. Specifically, electrodeposition of films based on aminopropyltriethoxysilane (APTS), and its codeposition with propyltrimethoxysilane (PrTMOS) and phenyltrimethoxysilane (PhTMOS) has been accomplished by applying negative potentials. The latter increases the concentration of hydroxyl ions on the stainless steel surface and thus catalyzes the condensation and deposition of the sol-gel films. The films were characterized by profilometry, electrochemical impedance spectroscopy (EIS), alternating current voltammetry (ACV), goniometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM and SEM analysis of codeposited APTS:PrTMOS films disclosed the structural changes induced by altering the deposition solution composition and the applied potential. Codeposited APTS:PhTMOS did not show any structural differences from their electrodeposited homopolymers, while Nano Scratch Test clearly revealed the changes in the elastic and adhesion properties, suggesting the formation of an APTS:PhTMOS composite. EIS of the films showed good resistance towards penetration of hydrophilic species, such as hexacyanoferrate. ACV measurements of the homo and codeposits showed the decrease of the interfacial capacity as a result of the electrochemical deposition. In essence, controllable sol-gel films with tunable chemical and physical properties based on controlling the combination of the precursors, pH and electrochemical properties can be electrodeposited on conducting surfaces. The application of this approach has been demonstrated by coating a stainless steel coronary stent.

Synthesis of Functionalized Mesoporous Material with Various Organo-Silanes

Two kinds of ordered mesoporous silicas, SBA-15 and MSU-H, have been synthesized and functionalized by direct and post synthesis method to widen their various application possibilities. In this study, phenyltrimethoxysilane (PTMS), methacryloxy-methyltrimethoxysilane (MAMTMS), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECETMS), and N(beta-aminoethyl)-gamma-aminopropylmethyldimethoxysilane (AEAPMDMS) were used as a silane precursor for the functionalization. The post synthesis was more effective method to sustain ordered pore structure than the direct synthesis method under our experimental conditions. The surface area and pore size of mesoporous silica SBA-15 and MSU-H decreased through the functionalization process. FT-IR and XPS results confirmed the functionalized silane existence in the SBA-15/MAMTMS. These functional groups (vinyl, epoxide, and amine group) could be useful for various applications such as a linker of functional organic materials or active metal for heterogeneous catalysts. As a practical instance, rhodium immobilized on the aminated SBA-15 was investigated as a 1-octene hydroformylation.

Algae–silica systems as functional hybrid materials

Microalgal cells were entrapped within two different sol–gel silica matrices with the aim of carrying out viability studies and developing active phases for sensor development. The first sol–gel system, based on methacryloxypropyltrimethoxysilane (MAPTS) and tetramethoxysilane (TMOS) monomers, was able to entrap lyophilized Chlorella vulgaris and Anabaena sp. PCC7120, but its rather non-porous nature limited the algal viability to the surface and fractures of the resulting hybrid material. However, this sol–gel material prepared with Chlorella tissue successfully performed as an active phase in the development of sensors for heavy-metal ions (e.g. Pb2+, Cu2+ and Cd2+) in water solution. The second sol–gel system was obtained using methyltrimethoxysilane (MTMOS), phenyltrimethoxysilane (PhTMOS) and TMOS monomers. Here, entrapped algae appeared to weakly interact with the resulting matrix probably due to its high hydrophobicity and also very low porosity. In this context, SEM and AFM studies carried out with the Anabaena-sol–gel material showed that algae could be removed from the polymeric network leaving traces having the algae’s peculiar three-dimensional shape. This opens the way to prepare imprinted materials using a soft lithographic approach, which could be potentially used as artificial receptors for electrochemical sensing of algae target species.

Novel semi-interpenetrating polymer network hybrid membranes for proton conduction

The synthesis and characterization of new hybrid organic–inorganic membranes (HOIMs) consisting of a semi-interpenetrating polymer network, for proton conduction, are described. Silane phases (SPs) were prepared by a sol–gel route and used in the synthesis of the hybrid membranes with cellulose triacetate (CTA) as organic matrix and dinonylnaphthalenesulfonic acid (DNSA) as proton carrier. For the preparation of the SPs dichlorodimethylsilane (DCDMSi) was crosslinked with tetraethoxysilane (TEOS) or phenyltrimethoxysilane (PTMS). FTIR spectroscopy was used to optimize this procedure and solutions 1H NMR and 29Si NMR were used to characterize the SPs. The SPs and the sulfonated compound contents were varied with respect to the organic polymer in order to optimize proton conductivity performance of the membrane. The latter property and membrane stability were determined by electrochemical impedance spectroscopy (EIS). Membranes prepared with CTA, DNSA and SP(TEOS), soaked in water for 16 days, showed conductivity values of 0.08–4.14 mS/cm and those prepared with SP(PTMS) of 5.52–23.44 mS/cm. Thermal analyses carried out using DSC and TGA techniques indicate that hybrid membranes are stable up to 175 °C. Results of membrane 29Si NMR and 13C NMR, ion-exchange capacity and water uptake are also reported.

High performance organic thin film transistor with phenyltrimethoxysilane-modified dielectrics

In this work, fabrication of organic thin film transistors (OTFTs) using a phenyltrimethoxysilane (PhTMS) modified SiO2 insulator greatly improves the device electrical properties over those with plain or octadecyltrichlorosilane (OTS) modified SiO2, particularly improves the carrier mobility, the subthreshold slope, and channel resistance resulted from reduced density of charge trapping states at the semiconductor/insulator interface. The pentacene OTFTs with modification from PhTMS (3.5‰ v/v) achieves carrier mobility of 1.03 cm2/V s, on/off current ratio of 1.98×105, and subthreshold slope of 0.20 V/decade. This work renders a new, simple approach to significantly improve the OTFT performance.

Amperometric biosensor for hydrogen peroxide based on coimmobilized horseradish peroxidase and methylene green in ormosils matrix with multiwalled carbon nanotubes

A novel amperometric biosensor for the analytical determination of hydrogen peroxide was developed. The fabrication of the biosensor was based on the coimmobilization of horseradish peroxidase (HRP), methylene green (MG) and multiwalled carbon nanotubes within ormosils; 3-aminopropyltrimethoxysilane (APTMOS), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ETMOS) and phenyltrimethoxysilane (PHTMOS). APTMOS determined the hydrophilicity/hydrophobicity of the ormosils and PHTMOS and ETMOS increased the physical and mechanical strength of the ormosil matrix. The ormosil modified electrodes were characterized with SEM, UV–vis spectroscopy and electrochemical methods. Cyclic voltammetry and amperometric measurements demonstrated the MG coimmobilized with HRP in this way, displayed good stability and could efficiently shuttle electrons between immobilized enzyme and electrode, and MWCNTs facilitated the electrocatalytic reduction of H 2O 2 at reduced over potential. The Micheaelis constant of the immobilized HRP was 1.8 mM, indicating a high affinity of the HRP to H 2O 2 without loss of enzymatic activity in ormosil matrix. The prepared biosensor had a fast response of H 2O 2, less than 10 s, and excellent linear range of concentration from 5 × 10 −7 to 2 × 10 −5 M with the detection limit of 0.5 μM (S/N = 3) under the optimum conditions. At the same time, the influence of solution pH, effect of enzyme amount, steady-state applied potential and temperature on the biosensor were investigated. The enzyme electrode retained about 90% of its initial activity after 30 days of storage in a dry state at 4 °C. The preparation of the developed biosensor was convenient and showed high sensitivity with good stability.