Formation Of Silica Network Research Articles

Bonding of activated ethylene–propylene rubber to surface–modified stainless steel

Film formation of self synthesized Polymer EPM–g–VTMDS (ethylene–propylene rubber, EPM, grafted with vinyltetramethyldisiloxane, VTMDS) was studied regarding bonding to adhesion promoter vinyltrimethoxysilane (VTMS) on oxidized 18/10 chromium/nickel–steel (V2A) stainless steel surfaces. Polymer films of different mixed solutions including commercial siloxane and silicone, dimethyl, vinyl group terminated crosslinker (HANSA SFA 42100, CAS# 68083-19-2, 0.35 mmol Vinyl/g) and platinum, 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complex Karstedt's catalyst (ALPA–KAT 1, CAS# 68478-92-2) were spin coated on V2A stainless steel surfaces with adsorbed VTMS thin layers in order to analyze film formation of EPM–g–VTMDS at early stages. Surface topography and chemical bonding of the high performance polymers on different oxidized V2A surfaces were investigated with X–ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and surface enhanced Raman spectroscopy (SERS). AFM and SEM as well as XPS results indicated that the formation of the polymer film proceeds via growth of polymer islands. Chemical signatures of the essential polymer contributions, linker and polymer backbones, could be identified using XPS core level peak shape analysis and also SERS. The appearance of signals which are related to Si–O–Si can be seen as a clear indication of lateral crosslinking and silica network formation in the films on the V2A surface.

Synthesis and Characterization of 50S8P Bioglass through Sol Gel Method

Bioactive glasses (BG) were applied in bone and dental applications as well as in tissue engineering. In this studies, a new bioglass 50S8P (50% SiO2, 22% CaO, 20% Na2O and 8% P2O5) with different aging time (3, 7, 10 and 15 days) was prepared by sol-gel method. These synthesized glasses were analyzed using X- ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The bioactivity of all BG is evaluated by incubating the BG powder in Hank's Balanced Salt Solution (HBSS) for 7, 14 and 21 days. Thermal analyses indicated the compositions can be stabilized at 700°C. XRD confirmed the primary crystalline phase was Na4Ca4Si6O18. Formation of silica network is established with the existence of functional group Si-O-Si (tetrahedral), confirmed with FTIR analyses. In vitro test confirm the apatite formation on the BG surface with characteristic of carbonate group (C-O) and P-O band noticed from FTIR and morphology of apatite formation on BG surface was observe using SEM

Synthesis, Characterization, and Investigation of Inhibitor Release of the Anticorrosion Sol–Gel Hybrid Nanocomposite Coatings

Corrosion protective coatings were developed on 1050 aluminum alloy through the sol–gel process using 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS), and diethylenetriamine (DETA) as the cross-linking agent. Two organic corrosion inhibitors (2-mercaptobenzothiazole and 2-mercaptobenzimidazole) were applied to induce inhibition properties. Salt spray method was employed to evaluate the corrosion protection performance. It was found that organic inhibitors improved the corrosion resistance of the coatings. Formation of silica networks from two precursors of GPTMS and TMOS in the presence of DETA curing agent was confirmed by FTIR. Distribution of silicon and sulfur, surface morphology and the presence of nanoparticles in the matrix were studied by SEM, EDX and TEM techniques. Physical and thermal properties of the coatings were investigated by water contact angle, Pull Off and DMTA tests, respectively. The results revealed that the presence of the organic inhibitors decreased the hydrophilicity and increased adhesion strength but has no significant effect on thermal properties. The controlled release of MBI was also investigated by UV-Vis spectrophotometry.

Influence of silane coupling agent on the properties of UV curable SiO2-PMMA hybrid nanocomposite

This work reports the preparation of UV-curable organic–inorganic hybrid nanocomposites synthetized by sol–gel method with the aim of obtaining highly transparent anti-abrasive coatings with long-term storage and stability for the protection of organic light emitting diodes (OLEDs). The inorganic phase is composed of tetraethoxysilane (TEOS) condensed under acid catalysis and mixed with tetrafunctionnal acrylate monomer and oligomer. Vinyltriethoxysilane (VTES), 3-methacryloxypropyltrimethoxysilane (MEMO), and 3-mercaptopropyltriethoxysilane (MTMO) are used as silane coupling agent and hybrid network modifier. Among the various parameters influencing the structure and properties of the hybrid, this work focuses on the nature and amount of coupling agent and their influence in terms of transparency, mechanical properties, and stability of the formulation. An optimum can be found in the silica to coupling agent ratio. Low level of functionalization leads to hybrids displaying poor optical performances and stability due to the coalescence of silica domains. On the contrary, an excess of functionalization reduces the abrasion resistance and the silica network formation. Changing the organic pendant of coupling agents greatly influences the properties of the coating by promoting the organic–inorganic balance. Dense and flexible as well as mechanically resistant coatings can be obtained from similar formulation by simply tuning the nature of the coupling agent depending of the needs of the application.

Oxidized cellulose reinforced silica gel: New hybrid for dye adsorption

A benign dicarboxylic cellulose/silica hybrid was synthesized through periodate-chlorite oxidation of cellulose followed by in-situ silica network formation through sol-gel process. The crosslinked 2, 3 dicarboxylic cellulose/silica hybrid showed a homogenous morphology and the internal structure shows rod-like structure for 2, 3 dicarboxylic cellulose with ∼5 nm in width. The current hybrid was investigated as a new adsorbent for methylene blue (MB) adsorption from aqueous solutions. The adsorption data were best represented by pseudo-second-order model and Langmuir isotherm model. The maximum adsorption is 526 mg/g according to Langmuir fitting. The obtained results suggested potential applications of dicarboxylic cellulose/silica hybrid for the efficient removal of MB from contaminated wastewater.

FURTHER EVIDENCE OF FILLER–FILLER MECHANICAL ENGAGEMENT IN RUBBER COMPOUNDS FILLED WITH SILICA TREATED BY LONG-CHAIN SILANE

ABSTRACT The present study discusses that filler–filler mechanical engagement resulting from the grafted long-chain silanes on the silica surface is indeed a reinforcing mechanism in rubber composites, as already speculated by nonlinear viscoelastic properties in our previous study. The existence and severity of such a phenomenon are assessed purely by isolating the energetic contribution of reinforcement from interfering with filler mechanical engagement in the silica network formation and breakdown processes. In a novel approach, the driving force of fillers to flocculate energetically at elevated temperatures was defined using surface energy theories, and it was adjusted to be similar in two composites having silica treated by short- and long-chain silanes. Filler–filler mechanical engagement was monitored by tracking network formation (filler flocculation) in a matrix of styrene–butadiene rubber and also by conducting various dynamic viscoelastic experiments on liquid paraffin suspensions having short- and long-chain silica of similar surface energy. Results consistently confirmed the existence of mechanical engagement between silica particles having the long-chain silane in both rubber compounds and paraffin suspensions. The results may find applications in the rolling resistance of tires, for example, where stabilization of the filler network by displacing the peak energy dissipation of the network breakdown from applied service strains to larger values would be of technical importance.

Development of New Composition of Bioactive Glass Powder from SiO<sub>2</sub>-CaO-Na<sub>2</sub>O-P<sub>2</sub>O<sub>5</sub> System through Melt-Derived Route

In this studies, melt-derived route was employed to fabricate new composition of bioactive glass (BG) from SiO2-CaO-Na2O-P2O5 system. Amorphous glass structure is confirmed through X-ray diffraction (XRD). Fourier transform infrared spectroscope (FTIR) confirmed the formation of silica network with the existence of functional groups Si-O-Si (bend), Si-O-Si (tetrahedral) and Si-O-Si (stretch) for all glass composition. The bioactivity of all BG is verified by incubation in Hank’s Balanced Salt Solution (HBSS) for 1h and 24h. Based on XRD pattern, it is confirmed that all glass composition remained in amorphous structure even after 24h of immersion with weak characteristic of carbonate group (C-O) and P-O band detected in FTIR analysis on carbonated hyrdoxyapatite (CHA) formation. Therefore, the objective to develop new composition of BG is achiveable despite the lack of CHA formation.

Characterization on melt-derived bioactive glass powder from SiO2-CaO-Na2O-P2O5 system

In the present work melt-derived route was employed to fabricate new compositions of bioactive glasses (BG) from SiO2-CaO-Na2O-P2O5 system. Thermal analyses indicated all compositions can be melted at lower temperature than 1400°C. X-ray fluorescence (XRF) revealed that the amount of SiO2 and Na2O detected within the fabricated glass was significantly different compared to the initial weight measured during glass compositions preparation. X-ray diffraction (XRD) confirmed the amorphous glass structure for all glass compositions. Formation of silica network is established with the existence of functional group Si-O-Si (tetrahedral), confirmed with Fourier transform infrared spectroscope (FTIR) analyses. The bioactivity of all BG is evaluated by incubating the BGs in Hank's Balanced Salt Solution (HBSS) for 1h, 24h, 7 and 30days. The finding showed that all glass compositions remained in amorphous structure even after 30days of immersion with weak characteristic of carbonate group (C-O) and P-O band detected in FTIR analysis on carbonated hydroxyapatite (CHA) formation.

Textural and morphological studies of transition metal doped SBA-15 by co-condensation method

The 3d transition metals were incorporated into SBA-15 matrix by co-condensation synthesis method. Very low concentrations of metals were introduced into silica framework by maintaining the metal to silica ratio in the synthesis gel at 0.01. The difference in hydrolysis rates of metal and silica precursors have led to textural modifications while demonstrating the structural integrity akin to pristine SBA-15. The physicochemical properties obtained offer some insights into the P123 micelle aggregation and mechanism of formation of silica network in the presence of metal salts under similar synthesis conditions of pure SBA-15. The metal doping into SBA-15 leads to increased pore diameters. Higher lattice constants (a0) observed in these samples are attributed to the increased pore wall thickness. The significant retention of the hexagonal mesostructure seen in LXRD indicates diminutive influence of metal salts at lower concentrations. Macroscopic morphologies studied by SEM show the formation of spheres along with conventional fibre-like rods. The 3d-transition metals were incorporated in SBA-15 by co-condensation method. The structural and textural properties of modified SBA-15 materials elucidate the increased pore wall thickness besides retaining their typical two dimensional hexagonal mesochannels with p6mm symmetry. The metal dopants have promoted the condensation of silica and induced morphological changes.

One-pot synthesis of pore-expanded hollow mesoporous silica particles

One-pot hard/soft template-free synthesis of hollow structured mesoporous silica particles (H-MSPs) with enlarged pore sizes was developed. By a simplified in situ hydrothermal treatment under mild conditions (70°C), a hollow interior evolution to a final size of ~150nm was successfully induced for the as-prepared particles from the sol–gel synthesis solution. The particles were evenly spherical with an average particle diameter of 350nm, as well as a mean pore size of 5nm in the mesoporous shell. Pore-swelling agents and aminosilane were demonstrated to contribute to the chemical irregularities in the silica network formation during particle growth, consequently leading to selective dissolution of the interior silica.

Poly(γ-glutamic acid)–silica hybrids with fibrous structure: effect of cation and silica concentration on molecular structure, degradation rate and tensile properties

Biodegradable organic/inorganic hybrid fibremats were prepared by electrospinning using poly(γ-glutamic acid) (γ-PGA) and glycidoxypropyl trimethoxysilane (GPTMS) for application in bone tissue engineering. Ca(OH)2 was used for preparing the calcium salt form of γ-PGA (Ca-γPGA), which is water-soluble. Effects of the amount of Ca(OH)2 mixed with γ-PGA on the chemical structure and characteristics of resulting hybrid fibremats were studied. ATR-FTIR data indicated that cross-linking between γ-PGA chains was achieved due to the coupling reaction between the polymer side chain and epoxy terminated group of GPTMS and silica network formation between GPTMS molecules. 13C CP/MAS-NMR and 29Si MAS-NMR spectra indicated that open epoxy groups in GPTMS reacted with each other and the rate of condensation between its silanol groups was lower when the added amount of Ca(OH)2 was smaller. Tensile test data demonstrated that elongation to failure was improved for the hybrid fibremat in comparison with just Ca-γPGA fibremats.

Bioactive organic-inorganic poly(CLMA-co-HEA)/silica nanocomposites.

A series of novel poly(CLMA-co-HEA)/silica nanocomposites is synthesized from caprolactone 2-(methacryloyloxy)ethyl ester (CLMA) and 2-hydroxyethyl acrylate (HEA) as organic comonomers and the simultaneous sol-gel polymerization of tetraethyloxysilane (TEOS) as silica precursor, in different mass ratios up to a 30 wt% of silica. The nanocomposites are characterized as to their mechanical and thermal properties, water sorption, bioactivity and biocompatibility, reflecting the effect on the organic matrix provided by the silica network formation. The nanocomposites nucleate the growth of hydroxyapatite (HAp) on their surfaces when immersed in the simulated body fluid of the composition used in this work. Proliferation of the MC3T3 osteoblast-like cells on the materials was assessed with the MTS assay showing their biocompatibility. Immunocytochemistry reveals osteocalcin and type I collagen production, indicating that osteoblast differentiation was promoted by the materials, and calcium deposition was confirmed by von Kossa staining. The results indicate that these poly(CLMA-co-HEA)/silica nanocomposites could be a promising biomaterial for bone tissue engineering.

Exploring GPTMS reactivity against simple nucleophiles: chemistry beyond hybrid materials fabrication

Hybrid materials with interpenetrating networks of silica and degradable polymers have the potential to outperform current biomaterials as their mechanical properties and degradation rates can be tightly controlled. GPTMS is one of the most widely used precursors for sol–gel hybrid fabrication. It can be used as the silica precursor or as a coupling agent to create hybrids with covalent bonds between the silica and organic components. Understanding its reactivity with nucleophilic groups on organic molecules in aqueous conditions is of key importance to hybrid synthesis. NMR spectrometry assisted by mass spectrometry was successfully used for the investigation of the reaction system of (3-glycidoxypropyl)trimethoxysilane (GPTMS) in the presence of different simple nucleophiles. Inorganic condensation and silica network formation is accelerated in the presence of propylamine; propanoic acid gives nucleophilic attack on the epoxy ring; propanol and propanthiol do not seem to participate in the reaction.

Reinforcement of Silica Aerogels Using Silane-End-Capped Polyurethanes

Proper selection of silane precursors and polymer reinforcements yields more durable and stronger silica aerogels. This paper focuses on the use of silane-end-capped urethane prepolymer and chain-extended polyurethane for reinforcement of silica aerogels. The silane end groups were expected to participate in silica network formation and uniquely determine the amounts of urethanes incorporated into the aerogel network as reinforcement. The aerogels were prepared by one-step sol-gel process from mixed silane precursors tetraethoxysilane, aminopropyltriethoxysilane (APTES), and APTES-end-capped polyurethanes. The morphology and mechanical and surface properties of the resultant aerogels were investigated in addition to elucidation of chemical structures by solid-state (13)C and (29)Si nuclear magnetic resonance. Modification by 10 wt % APTES-end-capped chain-extended polyurethane yielded a 5-fold increase in compressive modulus and 60% increase in density. APTES-end-capped chain-extended polyurethane was found to be more effective in enhancement of mechanical properties and reduction of polarity.

Bioactivity in silica/poly(γ-glutamic acid) sol–gel hybrids through calcium chelation

Bioactive glasses and inorganic/organic hybrids have great potential as biomedical implant materials. Sol–gel hybrids with interpenetrating networks of silica and biodegradable polymers can combine the bioactive properties of a glass with the toughness of a polymer. However, traditional calcium sources such as calcium nitrate and calcium chloride are unsuitable for hybrids. In this study calcium was incorporated by chelation to the polymer component. The calcium salt form of poly(γ-glutamic acid) (γCaPGA) was synthesized for use as both a calcium source and as the biodegradable toughening component of the hybrids. Hybrids of 40wt.% γCaPGA were successfully formed and had fine scale integration of Ca and Si ions, according to secondary ion mass spectrometry imaging, indicating a homogeneous distribution of organic and inorganic components. 29Si magic angle spinning nuclear magnetic resonance data demonstrated that the network connectivity was unaltered with changing polymer molecular weight, as there was no perturbation to the overall Si speciation and silica network formation. Upon immersion in simulated body fluid a hydroxycarbonate apatite surface layer formed on the hybrids within 1week. The polymer molecular weight (Mw 30–120kDa) affected the mechanical properties of the resulting hybrids, but all hybrids had large strains to failure, >26%, and compressive strengths, in excess of 300MPa. The large strain to failure values showed that γCaPGA hybrids exhibited non-brittle behaviour whilst also incorporating calcium. Thus calcium incorporation by chelation to the polymer component is justified as a novel approach in hybrids for biomedical materials.

Role of pH and temperature on silica network formation and calcium incorporation into sol–gel derived bioactive glasses

Bioactive glasses and inorganic/organic hybrids have great potential as implant materials. Bioactive glasses can bond to bone through the formation of a bone-like hydroxycarbonate apatite (HCA) layer and stimulate bone growth via their dissolution products. The brittle nature of these glasses can be combined with the toughness of a biodegradable polymer by forming a hybrid through the sol–gel process. However, for polymer incorporation, lower temperatures and milder pH conditions are required rather than the current method which uses pH < 1 and stabilisation at 600 °C. The impact of varying pH at low temperature processing (40 °C) on the inorganic component is unknown and must be investigated as a fundamental examination for hybrid research. This work seeks to combine pH control with a calcium source to examine the effect on porosity and silica network connectivity and to determine if raising the pH of synthesis can form a more highly connected glass without the need for high temperatures. Glass monoliths (70 mol% SiO2 and 30 mol% CaO) were fabricated, using calcium hydroxide as the calcium precursor and at different pH values (pH 0.5–5.5). With a view to hybrid synthesis, gels were dried at 40 °C and were compared with glasses made from identical gels that had been stabilised at 600 °C. When dried at 40 °C, gels synthesised at pH < 2 were not mesoporous whereas those formed at pH > 2 were mesoporous. This indicates a difference in gel formation about the isoelectric point of silicic acid, which was confirmed by 29Si solid state NMR. When immersed in simulated body fluid (SBF), the glasses stabilised at 600 °C were more porous, yet had a slower ion release rate than the gels dried at 40 °C. All gels and glasses formed an HCA layer in SBF; however, calcium was only incorporated into the silica network after stabilisation at 600 °C and thus a new way of incorporating calcium at low temperatures must still be found. This work is an important foundation for hybrid synthesis as raising the pH of the sol–gel process from pH < 1 to pH 5.5 was found to have no adverse effects on silica network formation and thus polymer can be incorporated into the sol–gel process at milder pH conditions without the concern of acid catalysed polymer degradation by chain scission.

Surface self-segregation, wettability, and adsorption behavior of core–shell and pentablock fluorosilicone acrylate copolymers

The surfaces of films cast from core–shell fluorosilicone acrylate copolymer (BA/MMA/DFHM and BA/MMA/DFHM/MPTMS/D4) latexes and linear pentablock fluorosilicone acrylate copolymer (PDMS-b-(PMMA-b-PDFHM)2) solutions are intensively investigated and compared by XPS, DCA, AFM, and QCM-D measurements. It is found that the molecular structures and in-solution aggregate structures of these well-defined copolymers have a dramatic influence on the surface structure formation, surface wetting, and adsorption behavior. The PDMS-b-(PMMA-b-PDFHM)2 film cast from chloroform solution with high concentration of low-density unimers is able to perform as strong surface self-segregation of fluorine-containing groups as core–shell copolymer latex films. The BA/MMA/DFHM/MPTMS/D4 in the core–shell latex particles exhibits the less pronounced surface self-segregation of silicon-containing groups than PDMS-b-(PMMA-b-PDFHM)2 due to the occurrence of cross-linking reactions between polysiloxane chains. Indeed, such reactions induce the formation of silica network within the film material, which immobilizes tightly the fluorinated groups on the film surface and thus endows the film with higher surface structural stability for water compared to PDMS-b-(PMMA-b-PDFHM)2 film with similar surface fluorine concentration and even higher silicon concentration. Still, the PDMS-b-(PMMA-b-PDFHM)2 film definitely demonstrates higher advancing and receding contact angles for water than BA/MMA/DFHM/MPTMS/D4 latex film in the case of synergism between surface enrichment of fluorine and silicon.

Cationic UV curing behavior and thermal properties of oxetane‐modified polysiloxane prepared from tetraethyl orthosilicate

AbstractThe oxetane‐modified polysiloxane (Oxe‐PSiO) was synthesized via the partial hydrolysis/condensation of tetraethyl orthosilicate (TEOS) and then transesterification reaction with 3‐ethyl‐3‐(hydroxymethyl)oxetane (EHO), and characterized by FT‐IR, 1H NMR, 13C NMR, and 29Si NMR spectroscopy. Using the water/TEOS molar ratios of 0.8–1.2, the number‐average molecular weights and polydispersity indices were obtained by GPC to range from 1.013 to 2.716 g mol−1 and around 2.0, respectively. The viscosity of Oxe‐PSiO prepared from the water/TEOS molar ratio of 1.2 sharply increased to 177,545 cps from 438 cps of that from the molar ratio of 0.8. A series of cationic UV‐curable formulations were prepared by blending the Oxe‐PSiO synthesized with the water/TEOS molar ratio of 1.0 into an commercial oxetane‐based resin, 3,3′‐[oxydi(methylene)]bis(3‐ethyloxetane), in different weight ratios. The photopolymerization kinetics studied by photo‐DSC in the presence of triphenylsulphonium hexafluoroantimonate as a cationic photoinitiator showed that both the maximum photopolymerization rate and final oxetane conversion in the cured film decreased with increasing Oxe‐PSiO loading mainly due to the sharp increase in viscosity. The DMTA and DSC results both indicated the improvement in thermal stability, showing 12 and 13.4°C, respectively, higher Tg for the cured film with 50 wt % Oxe‐PSiO loading compared with the pure polymer. Moreover, the temperatures (T10% and T50%) at the weight loss of 10 and 50% and final char yields measured by TGA increased with increasing Oxe‐PSiO content. After adding 50 wt % Oxe‐PSiO, compared with the pure polymer the T10% increased from 349 to 361°C, while the T50% increased from 409 to 424°C, and with a char yield increase of 8.2% at 800°C. In addition, its greatly increased crosslinking density due to the formation of silica network resulted in the enhancement in pencil hardness from B of the pure polymer to 2H grade. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Solid-State NMR Characterization of Phenylbenzimidazolesulfonic Acid Coencapsulated with Cetyltrimethylammonium in Mesoporous Silica Materials

The hydrophilic molecule phenylbenzimidazolesulfonic acid (PBSA) has been coencapsulated with cetyltrimethylammonium chloride (CTAC), an amphiphilic surfactant, via an in situ method in a mesoporous silica matrix. The effect of coencapsulation on texture and structure of the mesoporous silica host has been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen sorption experiments, and 29Si magic-angle spinning (MAS) NMR spectroscopy. It was clearly observed that the presence of PBSA led to different characteristics compared to the reference MCM-41 type organized mesoporous silica (OMS), which suggests that the active molecules perturb the silica network formation. The encapsulation of the hydrophilic PBSA molecule was found to be stable in aqueous media, indicating that strong interactions exist between PBSA and its environment (surfactant and silica framework). 1H−29Si and 1H−13C MAS NMR experiments evidenced their spatial proximity and confirmed the presence of interaction between PBSA and both CTA+ molecules and silanol of the silica framework. This NMR study gave an overall picture of the organic/inorganic interface.

An electrochemical glucose biosensor exploiting a polyaniline grafted multiwalled carbon nanotube/perfluorosulfonate ionomer–silica nanocomposite

A glucose biosensor was fabricated with loading of glucose oxidase (GOx) into a new organic–inorganic hybrid nanocomposite. The preparation involves formation of silica network into a Nafion (perfluorosulfonate ionomer) and subsequent loading of polyaniline grafted multiwalled carbon nanotubes (MWNT-g-PANI) onto Nafion–silica nanocomposite. Field emission scanning electron microscopy (FE-SEM) of Nafion–silica/MWNT-g-PANI composite reveals the presence of spherical silica particles (sizes in the range 250nm–1μm) and tubular MWNT-g-PANI particles. Chronoamperometry and cyclic voltammetry were used to evaluate the performance of biosensor towards glucose. The Nafion–silica/MWCNT-g-PANI/GOx biosensor exhibited a linear response to glucose in the concentration range of 1–10mm with a correlation coefficient of 0.9972, good sensitivity (5.01μA/mm), a low response time (∼6s), repeatability (R.S.D value of 2.2%) and along-term stability. The presence of silica network within Nafion and MWNT-g-PANI synergistically contributes to the performance of the biosensor towards the electrochemical detection of glucose.