Hybrid photochromic multilayer films based on chitosan and europium phosphomolybdate

Multilayer films based on chitosan and K₁₁[Eu^III(PMo₁₁O₃₉)₂] were prepared on different substrates using the layer-by-layer method. UV–Vis spectra of the films showed regular stepwise growth. X-ray photoelectron spectroscopy data confirmed the presence of chitosan and phosphomolybdate within the films and scanning electron microscopy images revealed a completely covered surface with a roughened texture. The film electrochemical responses and permeability were studied by cyclic voltammetry. Films revealed four surface-confined Mo-based reduction processes (Mo^VI → Mo^V). Studies with [Fe(CN)₆]^3?/4? and [Ru(NH₃)₆]^3+/2+ showed that film permeability depended on the film thickness and on the charge of the outer layer. Irradiation of films with UV light confirmed their photochromic properties through the colour change from transparent to blue. Colouration–discolouration cycles could be repeated up to 36 cycles without the loss of optical contrast, indicating high film photochromic stability. These results provided valuable insights for exploring the potential application of polyoxometalate-based films for the construction of photochromic devices.     

Influence of pH on the morphology and photocatalytic activity of CuO obtained by the sonochemical method using different surfactants

In this work, copper oxide II (CuO) was obtained using different surfactants (PVP, PEG and EDA), as well as without surfactant (WS), varying synthesis pH (8, 11 and 13). The powders were characterized by X-ray diffraction (XRD), field scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET), UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), photoluminescent properties and their photocatalytic properties were measured against the methylene blue dye under UV radiation. XRD patterns showed that a pH increase from 8 to 13 favors CuO single phase formation, whereas Cu₂(OH)₃(NO₃) secondary peaks appear at lower values. FTIR spectra confirmed the appearance of Cu₂(OH)₃(NO₃) through the vibrations related to the hydroxide nitrate. The SEM images showed the variations in morphology obtained through the different surfactants and the medium pH, in which, the morphology presents a leaf appearance with a lower value (pH =?8), while increasing the pH to 13, changed the morphology into agglomerate flower-like nanoparticles. The BET results showed that the samples obtained without surfactant and with PEG at pH =?8 had the highest and lowest surface area, being 18.935 and 4.531?m² g^?1, respectively. The photocatalytic activity shows that the CuO powders that have a small amount of Cu₂(OH)₃(NO₃) present better methylene blue dye degradability when illuminated by UV–Vis radiation.     

A novel biosensor based on electro-co-deposition of sodium alginate-Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>-graphene composite on the carbon ionic liquid electrode for the direct electrochemistry and electrocatalysis of myoglobin

A novel biosensor based on electro-co-deposition of myoglobin (Mb), sodium alginate (SA), Fe₃O₄-graphene (Fe₃O₄-GR) composite on the carbon ionic liquid electrode (CILE) was fabricated using Nafion as the film forming material to improve the stability of protein immobilized on the electrode surface, and the modified electrode was abbreviated as Nafion/Mb-SA-Fe₃O₄-GR/CILE. FT-IR and UV–vis absorption spectra suggested that Mb could retain its native structure after being immobilized in the SA-Fe₃O₄-GR composite film. The electrochemical behavior of the modified electrode was studied by cyclic voltammetry, and a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode, which was ascribed to the good electrocatalytic capability of Fe₃O₄-GR composite, the good biocompatibility of SA and the synergistic effects of SA and Fe₃O₄-GR composite. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α) and the electron transfer rate constant (k _s) were calculated as 0.982, 0.357 and 0.234 s^?1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) with wide linear range from 1.4 to 119.4 mmol/L, low detection limit as 0.174 mmol/L (3σ), good stability and reproducibility.     

TiO<Subscript>2</Subscript> porous ceramic/Ag–AgCl composite for enhanced photocatalytic degradation of dyes under visible light irradiation

TiO₂ porous ceramic/Ag–AgCl composite was prepared by incorporating AgCl nanoparticles within the bulk of TiO₂ porous ceramic followed by reducing Ag⁺ in the AgCl particles to Ag⁰ species under visible light irradiation. The porous TiO₂ ceramic was physically robust and chemically durable, and the porous structure facilitated the implantation of AgCl NPs. Compared with the bare TiO₂ ceramic, TiO₂ porous ceramic/Ag–AgCl composite exhibited higher photocatalytic performance for the degradation of MO and RhB under visible light irradiation. The reaction rate constants k of MO and RhB degradation over TiO₂ porous ceramic/Ag–AgCl composite was respectively 6.25 times and 3.62 times higher than those recorded over the bare TiO₂ porous ceramic. The photocatalytic activity showed virtually no decline after four times cyclic experiments under visible light irradiation. Scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectra and X-ray photoelectron spectroscopy were used to characterize the TiO₂ porous ceramic/Ag–AgCl composite.     

Electrochemical,spectroscopic and morphological characterization of electrostatic self-assembled hybrids of tetracationic phosphonium porphyrins and CdTe quantum dots

Cationic porphyrins (i.e., [Ttolyl(P-(C₆H₅)₃)₄]⁴⁺, where Ttolyl = 5,10,15,20-tetrakis tolylporphyrin and CdTe capped with glutathione) were electrostatically self-assembled via a layer-by-layer methodology onto ITO electrodes and characterized by UV–Vis spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and SEM-EDX microscopy. Cyclic voltammetry studies of the cationic porphyrin [Ttolyl(P-(C₆H₅)₃)₄]⁴⁺ demonstrated its ability to absorb both glassy carbon and ITO electrodes. The electrochemical properties of the hybrid porphyrin/quantum dot films (i.e., ITO/{[Ttolyl(P-(C₆H₅)₃)₄]⁴⁺/CdTe}_n, where n = 1–5 is the immersion step) were explored in buffer solutions in the presence or absence of the Fe(CN) ₆ ^3? /Fe(CN) ₆ ^4? redox couple at pH 7.0. The resistance to electron transfer determined by cyclic voltammetry and EIS is in agreement with the increase in the UV–Vis absorption of the material adsorbed onto the ITO surface for each newly assembled bilayer. The prepared bilayers exhibited an interesting homogeneous morphological distribution of CdTe quantum dots on the surface, which indicated the ability of [Ttolyl(P-(C₆H₅)₃)₄]⁴⁺ to organize CdTe nanoparticles on the ITO surface. EDX analysis of the bilayers confirmed the presence of Cd, Te, and S from the quantum dot. Linear sweep voltammetry indicated that ITO/{[Ttolyl(P-(C₆H₅)₃)₄]⁴⁺/CdTe}₅ has oxygen reduction electrocatalytic properties and demonstrated a synergetic effect between the cationic porphyrin and the CdTe quantum dot.     

Effect of oxidation debris on spectroscopic and macroscopic properties of graphene oxide

Oxidation debris (OD) and graphene oxide (GO) before and after OD removal were characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, mass spectroscopy, X-ray diffraction, transmission electron microscopy and potentiometric titration, respectively. OD removal decreased GO absorption intensity in UV/Vis spectra, caused changes in peak position and absorption intensity in FTIR spectra, and resulted in the decrease of I_D/I_G in Raman spectra. OD was amorphous and had higher content of acidic groups than purified GO. OD contributed 10–25% of overall surface charge density to unpurified GO in spite of small amount (ca. 1% mass). OD removal decreased significantly GO dispersibility in aqueous solution, but increased obviously the electrical conductivity of reduced graphene oxide (rGO) and the apparent density of compacted rGO. The removal of OD was necessary because of its striking effects on both GO spectroscopic and macroscopic properties. Batch desorption in NaOH solution was recommended for OD removal from as-prepared graphite oxide because of slow OD desorption kinetics.     

Li:Ce co-doped CdO films synthesized by SILAR method: Effects of rare earth element Ce content on the physical attributes

Undoped, Li-doped (Li_0.02Cd_0.98O) and Li:Ce co-doped (Ce_x Li_0.02Cd_0.98-xO (x?=?0.005, 0.01 and 0.02)) CdO nanofilms were prepared by a successive ionic layer adsorption and reaction (SILAR) process. The effects of the Li and Li:Ce doping on the main physical properties such as crystal structure, surface morphological characteristics and optical features like bandgap and transmittance of obtained these films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis spectrophotometer respectively. X-ray diffractogram analysis verified that the synthesized CdO films pertain to the cubic structure. XRD analysis indicated the growth of CdO with polycrystalline form for preferential orientation along the (111) and (200) plane. It is obviously seen from the SEM micrographs that Li doping and Li:Ce co-doping induce remarkable changes in the CdO surface morphology. The UV–Vis spectroscopy analysis results show that the (2.0% Li+1.0% Ce) Li:Ce co-doped CdO films exhibits maximum transmittance (27%) in the range between 300 and 1100?nm and high optical bandgap energy (E_g =2.92?eV).     

Layer-by-layer assembly of myoglobin and nonionic poly(ethylene glycol) through ion-dipole interaction: An electrochemical study

Nonionic poly(ethylene glycol) (PEG) and myoglobin (Mb) were successfully assembled into {PEG/Mb}_n layer-by-layer films on various solid surfaces. Quartz crystal microbalance (QCM), UV-vis spectroscopy and cyclic voltammetry (CV) were used to monitor and confirm the film growth and characterize the films. The Mb in stable {PEG/Mb}_n films showed a quasi-reversible CV response for its heme Fe(III)/Fe(II) redox couple, and was used to electrocatalyze the reduction of various substrates. The interaction between PEG and Mb in the assembly was investigated in detail. A series of comparative experiments showed that the ion-dipole interaction between positively charged groups on the Mb surface and electronegative ether oxygen groups of PEG would be the main driving force for the assembly of {PEG/Mb}_n films, while other interactions such as hydrogen bonding and/or hydrophobic interaction may also play an important role in stabilizing the films in blank buffers.     

Electrochromic properties of Al doped B-subsituted NiO films prepared by sol–gel

In this paper, Al doped B-substituted NiO films were prepared by sol–gel method. The effect of the Al content on the structure of the Al_xB_0.15NiO films were studied with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical and EC properties were examined by cyclic voltammetric (CV) measurements and UV–Vis spectrophotometry, respectively. Al doping could prevent the crystallization of the films, which exhibited much better electrochemical and electrochromic properties than undoped samples. The bleached state absorbance could be significantly lowered when the Al added. EC efficiencies measured at λ = 500 nm of the films with different Al doping content reach ～30 cm² C^?1, with a change in transmittance up to 70%.     

Bifunctional mesoporous Cu–Al–MCM-41 materials for the simultaneous catalytic abatement of NOx and VOCs

This study explored the possibility of using waste organic solvent as the source of volatile organic compound (VOC) and it served as a reducing agent of selective catalytic reduction (SCR) deNO_x process, in which the VOC itself can be catalytically oxidized on the mesoporous Cu and/or Al substituted MCM-41 catalysts. The synthesized Cu–Al–MCM-41 catalysts were extensively characterized by powder low-angle X-ray diffraction (XRD), N₂ adsorption–desorption measurements, transmission electron microscopy (TEM), UV–Visible diffuse reflectance spectroscopy (UV–Vis DRS), ²⁷Al magic angle spinning-nuclear magnetic resonance spectroscopy (MAS-NMR), electron paramagnetic resonance spectroscopy (EPR) and inductively coupled plasma–mass spectrometer (ICP–MS) analysis. The XRD, TEM and N₂ adsorption–desorption studies clearly demonstrated the presence of a well ordered long range hexagonal array with uniform mesostructures. The Cu–Al–MCM-41 materials showed a better long-term-stability than that of copper ion-exchanged H–ZSM-5 (Cu–ZSM-5) zeolite. The Cu–Al–MCM-41 material was found to be an efficient catalyst than that of Cu–MCM-41 without aluminum for the simultaneous catalytic abatement of NO_x and VOCs, which was attributed to the presence of well dispersed and isolated Cu²⁺ ions on the Cu–Al–MCM-41 catalyst as observed by UV–Vis DRS and EPR spectroscopic studies. And the presence of aluminum (Al³⁺ ions) within the framework of Cu–Al–MCM-41 stabilized the isolated Cu²⁺ ions thus it led to higher and stabilized activity in terms of NO_x reduction.     

Enhanced photocatalytic activity of highly transparent superhydrophilic doped TiO2 thin films for improving the self-cleaning property of solar panel covers

Undoped and metal doped nanocrystalline TiO₂ transparent thin films were synthesized on glass substrates via sol-gel/dip-coating method. TiO₂ thin film coatings can be applied to the surfaces of solar panels to impart self-cleaning properties to them. The structural and optical properties of few nanometer-thick films were characterized by XRD, SEM, CA, AFM, XPS, and UV–Vis spectrophotometry techniques. The stoichiometric TiO₂ films crystallized in anatase phase, with a particle size of ～100 nm, which were uniformly distributed on the surface. The prepared films with a roughness of ～1–5 nm, increased the hydrophilicity of the glass surface. Reducing the amount of Ti precursor (X) favored the improvement of film quality. To improve the photocatalytic activity of the TiO₂ thin film, it was doped with Ni, Cd, Mo, Bi and Sr metal ions. The effect of metal doping on the photocatalytic activity of the films was investigated using the degradation process of methylene blue (MB) dye as the model contaminant. Among the prepared coatings, the Sr–TiO₂ film showed the highest efficiency for MB degradation. It increased the dye degradation efficiency of the films under both UV and Vis lights. The kinetic investigations also showed that the degradation of MB by TiO₂ and M ? TiO₂ films obeyed the pseudo-first order kinetics.     

Microwave photocatalysis III. Transition metal ion‐doped TiO2 thin films on mercury electrodeless discharge lamps: preparation,characterization and their effect on the photocatalytic degradation of mono‐chloroacetic acid and Rhodamine B

BACKGROUND: Mercury electrodeless discharge lamps (Hg‐EDLs) were used to generate UV radiation when exposed to a microwave field. EDLs were coated with doped TiO₂ in the form of thin films containing transition metal ions Mⁿ⁺ (M = Fe, Co, Ni, V, Cr, Mn, Zr, Ag). Photocatalytic degradation of mono‐chloroacetic acid (MCAA) to HCl, CO₂, and H₂O, and decomposition of Rhodamine B on the thin films were investigated in detail. RESULTS: Polycrystalline thin doped TiO₂ films were prepared by dip‐coating of EDL via a sol–gel method using titanium n‐butoxide, acetylacetone, and a transition metal acetylacetonate. The films were characterized by Raman spectroscopy, UV/Vis absorption spectroscopy, X‐ray photoelectron spectroscopy (XPS), electron microprobe analysis and by atomic force microscopy (AFM). The photocatalytic activity of doped TiO₂ films was monitored in the decomposition of Rhodamine B in water. Compared with the pure TiO₂ film, the UV/Vis spectra of V, Zr and Ag‐doped TiO₂ showed significant absorption in the visible region, and hence the photocatalytic degradation of MCAA had increased. The best apparent degradation rate constant (0.0125 min^?1), which was higher than that on the pure TiO₂ film by a factor of 1.7, was obtained with the Ag(3%)/TiO₂ photocatalyst. The effect of doping level of vanadium acetylacetonate on the photocatalytic efficiency of the V‐doped TiO₂ was determined. CONCLUSIONS: Transition metal ion‐doped TiO₂ thin films showed significant absorption in the visible region. The metal doped TiO₂ photocatalyst (with an appropriate amount of V, Zr and Ag) on the Hg‐EDLs increased the degradation efficiency of MCAA in a microwave field. Copyright © 2009 Society of Chemical Industry     

High Yield Synthesis,Detailed Spectroscopic Characterization and Electrochemical Fate of Novel Cationic Surfactants

Two new cationic surfactants, N-(dodecanoyl(ethylammonio)carbonothioyl)-N-ethylbenzenaminium bromide and N-(dodecanoyl(ethylammonio)carbonothioyl)-N-ethyl-N-phenylbenzenaminium bromide were synthesized with a high yield by the reaction of appropriate amounts of lauryl chlorides, potassium thiocyanate, amine and alkyl halides. The structures were characterized by ¹H-NMR, ¹³C-NMR, FTIR and UV–Vis spectroscopy. Cyclic, square wave and differential pulse voltammetry were used to investigate the electrochemical fate of both surfactants over a wide pH range.     

Fabrication of a graphene oxide–gold nanorod hybrid material by electrostatic self-assembly for surface-enhanced Raman scattering

An electrostatic self-assembly procedure was used to fabricate graphene oxide (GO) and gold nanorod (AuNR) hybrids (GO–AuNR), in which poly (N-vinyl-2-pyrrolidone) was used as a stabilizing surfactant to prevent the aggregations of GO sheets. AuNRs were loaded onto the surface of GO, which was confirmed by zeta potential measurements, transmission electron microscopy, atomic force microscopy, UV–Vis–NIR and Raman spectroscopy. The GO–AuNR materials show a great increase of Raman signals for adsorbed aromatic dye molecules, which was demonstrated using cationic and anionic aromatic dyes as probe molecules.     

Interaction between myoglobin and hyaluronic acid in layer-by-layer structures—An electrochemical study

The layer-by-layer (LBL) self-assembled film construction of the biocompatible polymer hyaluronic acid (HA) and single heme redox protein, myoglobin (Mb) is described. The films were built upon gold electrode substrates, both gold quartz crystal electrodes and bulk gold (Au(bulk)) electrodes, and formation of the LBL films was gravimetrically monitored by an electrochemical quartz crystal microbalance. The electrochemical properties of the hyaluronic acid/myoglobin films ({HA/Mb}_n) were investigated after each deposition step using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The CV response presented an oxidation peak at +0.3 V vs. SCE, not characteristic of the redox protein myoglobin, and, the peak current decreased slightly with each additional bilayer. CV at Au(bulk) electrodes in pH 5.0 acetate buffer solution, containing Mb, presented the same oxidation peak as observed at {HA/Mb}_n modified electrodes, confirming the presence of the same electroactive species. The Mb oxidation peak current depends linearly on scan rate, characteristic of adsorbed thin-layer electrochemical systems, attributed to free adsorbed heme. Impedance spectra, recorded after deposition of each bilayer, were in agreement with the cyclic voltammetry observations.     

Electrochemical characteristics of boron-doped,undoped and nitrogen-doped diamond films

Boron-doped, undoped and nitrogen-doped diamond films were synthesized by microwave plasma assisted chemical vapor deposition (MP-CVD). Raman spectroscopy, XPS, EPMA and UV–Vis were used to characterize the properties of the synthesized films. Electrochemical characteristics for several redox systems on the three kinds of diamond films were examined. For Li⁺/Li (E⁰=−3.05 V) and H⁺/H₂ (E⁰=0.00 V) redox couples, the marked differences in cyclic voltammetric (CV) behaviors were observed on the nitrogen-doped diamond films, whereas for Fe(CN)³⁻/⁴⁻ (E⁰=0.36), Au/AuCl₄⁻ (E⁰=1.00) and O₂/H₂O (E⁰=1.23 V) couples, the CV behaviors on the nitrogen-doped films were similar to those on the boron-doped or undoped diamond films. The significant differences of CV behaviors could be explained by hypothesizing that the electron transfers of the redox species in the solution on diamond electrodes happened at the top of valence band together with the surface doping model suggested by F. Maier and colleagues [F. Maier, M. Riedel, B. Mantel, J. Ristein, L. Ley, Phys. Rev. Lett. 85 (2000) 3472].     

Amperometric hydrogen peroxide biosensor based on a modified gold electrode with silver nanowires

A novel amperometric biosensor for the detection of hydrogen peroxide (H₂O₂) was prepared by immobilizing horseradish peroxidase (HRP) on highly dense silver nanowire (Ag-NW) film. The modified electrode was characterized using UV–Vis spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The electrochemical performances of the electrode were studied by cyclic voltammetry and chronoamperometry. The HRPs immobilized on the surface of Ag-NWs exhibited an excellent electrocatalytic response toward reduction of H₂O₂. The resulting Ag-NW modified sensor showed a sensitivity of ~2.55 μA μM⁻¹ (correlation coefficient r = 0.9969) with a linear range of 4.8 nM–0.31 μM. Its detection limit was 1.2 nM with a signal-to-noise ratio of 3. The Michaelis–Menten constant K_M^app and the maximum current density I _max of the modified electrode were 0.0071 mM and 8.475 μA, respectively. The preparation process of the proposed biosensor was convenient, and the resulting biosensor showed high sensitivity, low detection limit and good stability.     

Loading of myoglobin into layer-by-layer films assembled by concanavalin A and dextran based on their biospecific recognition: An electrochemical study

Lectin protein concanavalin A (Con A) and polysaccharide dextran (Dex) were assembled into {Con A/Dex}_n layer-by-layer (LBL) films by biospecific affinity between them. The films were then immersed in myoglobin (Mb) solution to load Mb into the films, designated as {Con A/Dex}_n-Mb. Quartz crystal microbalance (QCM), cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were used to monitor the growth of {Con A/Dex}_n films and characterize the {Con A/Dex}_n-Mb films. The Mb in {Con A/Dex}_n-Mb films showed a quasi-reversible CV peak pair for its heme Fe(III)/Fe(II) redox couple, and the Mb-loaded films could be used to electrocatalyze the reduction of oxygen and hydrogen peroxide. The formal potential of Mb (E°′) and the surface concentration of electroactive Mb (Γ*) in the films were affected significantly by the environmental pH. The driving forces of {Con A/Dex}_n film assembly and Mb loading into the films were investigated. This model protein-loaded LBL films may guide us to develop novel electrochemical biosensors based on the direct electrochemistry of enzymes.     

Effect of GO/CS/PbS nanocomposite films on tetraethyoxysilane sensing

In this work, a new method for generating highly fluorescent graphene oxide (GO)/chitosan (CS)/PbS nanocomposite films in a mild environment was developed via electrostatic interactions and in situ growth methods. The growth of PbS nanoparticles was initiated by ion complexation with –NH₂ in the CS chain, followed by the thioacetamide treatment of S^2? obtained from decomposed samples. Moreover, the distinct features of the nanocomposite films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, UV–vis, and scanning electron microscopy. Polymer molecules could control nucleation and PbS growth on the surface of GO/CS films to stabilize nanoparticles. The fluorescence spectral measurements clearly showed that the fluorescence of the nanocomposite film was gradually enhanced with tetraethyoxysilane addition. This enhancement was ascribed to the gradual decrease in solvent polarity. Moreover, the CS conformation changed in an extension state, which increased the distance between PbS and GO and reduced their quenching effect. The fluorescence results revealed that the GO/CS/PbS nanocomposite films were sensitive to tetraethoxysilane and could easily be recovered and reused for sensing. Therefore, the nanocomposite films may be specific sensor materials for tetraethoxysilane. Such a simple and efficient strategy would provide an opportunity for the large-scale production of various heterostructures with wide potential applications in the sensing field.     

Polypyrrole–multiwalled carbon nanotubes composites as immobilizing matrices of ascorbate oxidase for the facile fabrication of an amperometric vitamin C biosensor

An amperometric vitamin C biosensor was facilely fabricated by the immobilization of ascorbate oxidase (AO) on polypyrrole (PPy)–multiwalled carbon nanotubes (MWCNTs) composites with a one‐step electrodeposition technique in a 0.05M phosphate buffer solution (pH 6.5). The cyclic voltammetry, IR spectral analysis, electrochemical impedance spectroscopy, and scanning electron microscopy measurements indicated that AO was successfully immobilized on the PPy–MWCNT composites. The optimization of the biosensor parameters, including the working potential, pH, and temperature, was investigated in detail. The proposed biosensor showed a linear range of 5 × 10^?5 to 2 × 10^?2 M with a detection limit of 0.3 μM, a sensitivity of 25.9 mA mM^?1 cm^?2, and a current response time less than 20 s under the optimized conditions. The apparent Michaelis–Menten constant together with the apparent activation energy indicated that the proposed biosensor exhibited a high bioaffinity and a good enzyme activity. In addition, the biosensor also showed good operational and storage stabilities. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012