Synthesis of tapioca cellulose-based poly(hydroxamic acid) ligand for heavy metals removal from water

A graft copolymerization was performed using free radical initiating process to prepare the poly(methyl acrylate) grafted copolymer from the tapioca cellulose. The desired material is poly(hydroxamic acid) ligand, which is synthesized from poly(methyl acrylate) grafted cellulose using hydroximation reaction. The tapioca cellulose, grafted cellulose and poly(hydroxamic acid) ligand were characterized by Infrared Spectroscopy and Field Emission Scanning Electron Microscope. The adsorption capacity with copper was found to be good, 210 mg g^?1 with a faster adsorption rate (t_1/2 = 10.5 min). The adsorption capacities for other heavy metal ions were also found to be strong such as Fe³⁺, Cr³⁺, Co³⁺ and Ni²⁺ were 191, 182, 202 and 173 mg g^?1, respectively at pH 6. To predict the adsorption behavior, the heavy metal ions sorption onto ligand were well-fitted with the Langmuir isotherm model (R² > 0.99), which suggest that the cellulose-based adsorbent i.e., poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability was checked by the sorption/desorption process for six cycles and the sorption and extraction efficiency in each cycle was determined. This new adsorbent can be reused in many cycles without any significant loss in its original removal performances.     

A non‐volatile,bistable, and rewritable memory device fabricated with poly(nitroxide radical) and silver salt layers

A non‐volatile, bistable, and rewritable organic memory device was successfully fabricated with the layers of poly(2,2,6,6‐tetramethylpiperidine‐1‐oxyl methacrylate) (PTMA) and poly(methyl methacrylate) (PMMA) containing silver salt. The PTMA layer was employed as a p‐dopable material, while the silver salt‐dispersed PMMA layer acted as an n‐dopable material. The ON–OFF ratio between low‐conductivity and high‐conductivity states amounted to more than four orders of magnitude, and the retention time was longer than 10³ sec. The device was characterized by excellent rewritability. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and applications of porous spg (shirasu porous glass) microspheres

Fairly uniform porous microspheres of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) were synthesized using a particular microporous glass membrane (SPG). Average diameters of these spheres are from 2.5 to 38 μm with the coefficient of variation (CV) around 10%. A maximum specific surface area of 370 m² /g was achieved. Uniform dispersion of MMA droplets was successfully prepared only when the swelling process reported by Higuchi and Misra was adopted. Two potential applications, one as a packing material for column chromatography, and the other as a carrier of enzyme immobilization, were demonstrated.     

Sulfonated poly(ether ether ketone) as an alternative charged material to poly(vinyl chloride) in the design of ion-selective electrodes

To date, poly(vinyl chloride) (PVC) is the most used polymer in the design of ion selective electrode (ISE) membranes. This paper is focused on the use of sulfonated poly(ether ether ketone) (SPEEK) as an alternative material to PVC for the design of ISEs. SPEEK of the desired degree of sulfonation is synthesized from poly(ether ether ketone) (PEEK). An NH₄⁺-ISE has been chosen as a model electrode to study the efficiency of SPEEK as polymer matrix of the membrane. The material was evaluated in ionophore free ion exchanger membranes as well as in ion-selective electrodes membranes containing nonactine as ionophore. Analytical performance parameters of the prepared electrodes were evaluated. The electrodes show a slope between 50 and 60 mV dec⁻¹ depending on both the calibration medium and the membrane composition. A linear range of response between 10⁻⁴ and 1.0 M and a lifetime of 1-2 months were obtained. The interferences of cations such us Ca²⁺, Na⁺, Li⁺ and K⁺ over the prepared ISEs are studied as well. Although the plasticizer in the SPEEK based membrane matrix is not necessary, its presence improves the sensibility. This makes SPEEK a good potential choice over alternative membrane matrices reported in the literature and a promising platform for the establishment of membrane components.     

Nanohybrids based on polymeric ionic liquid prepared from functionalized MWCNTs by modification of anionically synthesized poly(4‐vinylpyridine)

We report the synthesis of a composite material comprised of poly(4‐vinylpyridine) (P4VP) grafted on multiwall carbon nanotubes (MWCNTs) and the preparation of a nanohybrid via quaternization of the nitrogen atom per monomeric unit of the polymer chains. 4‐Vinylpyridine was polymerized anionically using high vacuum techniques and was reacted with MWCNTs under vacuum to be grafted on the polymer segments. The composite material was soluble in common solvents and the dispersion of the carbon nanotubes was improved after quaternization due to the formation of polymeric ionic liquid (PIL) of the MWCNTs‐g‐[P4VP‐r‐poly(4ViEtPy⁺Br^‐)] type. The successful synthesis was confirmed with Fourier‐transform infrared and Raman spectroscopies, whereas differential scanning calorimetry was adopted to verify the stability of the polymer's glass transition temperature before and after grafting on the MWCNTs. Moreover, thermogravimetric analysis was used for examining the thermal stability and the PIL formation of the composite. Energy dispersive spectroscopy measurements confirm the precipitation of silver bromide when the MWCNTs‐g‐[P4VP‐r‐poly(4ViEtPy⁺Br^‐)] is reacted with silver nitrite indicating the successful quaternization and formation of the appropriate PIL. High temperature size exclusion chromatography was used for the determination of the molecular characteristics (average molecular weight by number $\overline M _n$ , polydispersity I) of the homopolymer obtained from the filtration of the composite material. Finally, field‐emission scanning electron microscopy was used to verify the successful grafting of the polymer to the MWCNTs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Role of counteranions in polymeric ionic liquid-based solid-phase microextraction coatings for the selective extraction of polar compounds

A polymeric ionic liquid (PIL) poly(1-vinyl-3-hexylimidazolium chloride) (poly(ViHIm⁺Cl⁻)) was designed as a coating material for solid phase microextraction (SPME) to extract polar compounds including volatile fatty acids (VFAs) and alcohols. The extracted analytes were analyzed by using gas chromatography (GC) coupled with flame ionization detection (FID). Extraction parameters of the HS–SPME–GC–FID method, such as ionic strength, extraction temperature, pH and extraction time were optimized. Calibration studies were carried out under the optimized conditions to further evaluate the performance of the PIL-based SPME coating. For comparison purposes, the PIL poly(1-vinyl-3-hexylimidazolium bis[(trifluoromethyl)sulfonyl]imide) (poly(ViHIm⁺NTf₂⁻)) was also used as the SPME coating to extract the same analytes. The results showed that the poly(ViHIm⁺Cl⁻) PIL coating had higher selectivity towards more polar analytes due to the presence of the Cl⁻ anion which provides higher hydrogen bond basicity than the NTf₂⁻ anion. The limits of detection (LODs) determined by the designed poly(ViHIm⁺Cl⁻) PIL coating ranged from 0.02 μg L⁻¹ for octanoic acid and decanoic acid and 7.5 μg L⁻¹ for 2-nitrophenol, with precision values (as relative standard deviation) lower than 14%. The observed performance of the poly(ViHIm⁺Cl⁻) PIL coating was comparable to previously reported work in which commercial or novel materials were used as SPME coatings. The selectivity of the developed PIL coatings was also evaluated using heptane as the matrix solvent. This work demonstrates that the selectivity of PIL-based SPME coatings can be simply tuned by incorporating different counteranions to the sorbent coating.     

Synthesis and electrochemical properties of polypyrrole-coated poly(2,5-dimercapto-1,3,4-thiadiazole)

A new composite cathode active material, conductive polypyrrole (PPy)-coated poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) was prepared as a thin film via the surfactant template (TFST) technique. The formation of the uniform and well-connected film on the surface of PDMcT particles was confirmed by Fourier transform infrared spectra (FT-IR) and transmission electron micrographs (TEM). By cyclic voltammetry and galvanostatic charge–discharge tests, the coated composite showed a better electrochemical performance than PDMcT, such as enhanced redox processes and improved coulumbic efficiency, etc. The electrical conductivity of the material reached to 10⁻³ S cm⁻¹ and an initial discharge capacity of 250 mAhg⁻¹ was obtained. Moreover, it showed a slower fading of discharge capacity than PDMcT when used as cathode material in secondary lithium batteries with liquid electrolyte solution.     

Enhanced performance of lithium polymer batteries using a V2O5–PEG composite cathode

A new concept is proposed to realize solid-state high-performance lithium polymer batteries in which two different polymers are used as ionically conductive matrices in the cathode and in the separator. A solid, low molecular weight poly(ethylene glycol) was used in the cathode while a blend with a higher molecular weight poly(ethylene oxide) (PEO) was used in the separator. The enhanced transport properties in the cathodic compartment allow us to discharge the battery (190 mAh g⁻¹) at a moderate temperature (65°C) in a reasonable time (about 3.3 h). Batteries cycled at 100°C showed enhanced performance with respect to PEO-based batteries. At a power density of about 416 W kg⁻¹, energy density as high as 460 Wh kg⁻¹, based on the weight of the active material, was achieved in about 1 h of discharge. The work was developed within the ALPE (Advanced Lithium Polymer Electric Vehicle Battery) project, an Italian integrated project devoted to the realization of lithium polymer batteries for electric vehicle applications, in collaboration with the Osaka National Research Institute.     

Photophysical Studies on Terpyridine-Eu3+ Complexes in Sol-Gel Nanocomposite Materials

The luminescence of the terpyridine-Eu³⁺-complex associated with poly(ethyleneoxide) or poly(propyleneoxide) chains has been studied in various fluid or solid environments including silica/poly(alkyleneoxide) nanocomposite materials. Strongly luminescent materials are obtained. Their emission can be tuned by varying the organic/inorganic content and, generally, the structure of the host material. In this respect, the complex luminescence itself is a sensor of the structural aspects of the host material.     

Poly(thieno[3,4‐b]‐1,4‐oxathiane) and poly(3,4‐ethylenedioxythiophene‐co‐thieno[3,4‐b]‐1,4‐oxathiane)/poly(styrene sulfonic sodium): Preparation,characterization, and optoelectronic performance

In this work, the asymmetrical analog of 3,4‐ethylenedioxythiophene (EDOT), thieno[3,4‐b]‐1,4‐oxathiane (EOTT), was synthesized and chemically polymerized first in aqueous solution using poly(styrene sulfonic sodium) (PSS) as the polyelectrolyte to yield poly(thieno[3,4‐b]‐1,4‐oxathiane) (PEOTT)/PSS. As‐formed film exhibited low electrical conductivity (～10^?4 S/cm). Alternatively, EOTT together with EDOT (in different molar ratio of 1:1 and 1:5) was copolymerized and the polymer poly(EOTT‐co‐EDOT)/PSS had electrical conductivity of 10^?1 S/cm. After dimethyl sulfoxide (DMSO) treatment, the electrical conductivity was enhanced to 10⁰ S/cm; however, the conductivity of the above homopolymer was reduced (～10^?5 S/cm). Raman spectroscopy was used to interpret conductivity enhancement or reduction after DMSO treatment. The conductivity decrease of PEOTT/PSS compared to poly(EOTT‐co‐EDOT)/PSS may arise from the conformational change of PEOTT backbone from the quasi‐planar to the distorted planar mode induced by PSS^–/PSSH through ionic interaction. Kinetic studies revealed that the copolymer had high coloration efficiencies (375 cm²/C), low switching voltages (?0.8 to +0.6 V), decent contrast ratios (45%), moderate response time (1.0 s), excellent stability, and color persistence. An electrochromic device employing poly(3‐methylthiophene) and poly(EOTT‐co‐EDOT)/PSS as the anode and cathode materials was also studied. From these results, poly(EOTT‐co‐EDOT)/PSS would be a promising candidate material for organic electronics. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2285–2297     

Synthesis and characterization of new poly(ether amide)s based on a new cardo monomer

A new cardo diamine monomer 3, 3‐bis‐[4‐{2′trifluoromethyl 4′‐(4″‐aminophenyl) phenoxy} phenyl]‐2‐phenyl‐2, 3‐dihydro‐isoindole‐1‐one ( 4 ) has been synthesized from potentially cheap phenolphthalein as the starting material. This diamine was used for the synthesis of a new poly(ether amide) and two co‐poly(ether amide)s using 4, 4′‐diaminodiphenyl ether (ODA) as co‐monomer by direct solution polycondensation with 5‐t‐butyl iso‐phthalic acid. These new polymers showed inherent viscosities of 0.48–0.62 dL g^?1. The resulting poly(ether amide) and co‐poly(ether amide)s were readily soluble in polar aprotic solvents like NMP, DMF, DMAc, DMSO, and pyridine. The polymers have been fully characterized by ¹H and ¹³C NMR, FTIR spectroscopy, and elemental analysis. These polymers showed glass transition temperatures in the range of 267–310°C. Thermogravimetric analysis indicated high thermal stability of these polymers at 5 and 10% weight loss temperature in air above 357°C and 419°C, respectively. The poly(ether amide) films cast from DMAc were flexible with tensile strength up to 91 MPa, elongations at break up to 11%, and modulus of elasticity up to 1.82 GPa. X‐ray diffraction measurements indicate the amorphous nature of the poly(ether amide)s. Copyright © 2009 John Wiley & Sons, Ltd.     

A new electrochromic material from an indole derivative and its application in high-quality electrochromic devices

A novel electrochromic material, poly(indole-6-carboxylic acid) (PIn), and its application in electrochromic devices (ECDs) are discussed. PIn was switched between yellow in the reduced state and green in the oxidized state. Electrochromic switching of PIn film shows that it has fast switching time and high optical contrast. ECD based on PIn and poly(3,4-ethylenedioxythiophene) (PEDOT) was also fabricated and characterized. The response time of this device was found to be 1.0 s and the optical contrast was 45%. The coloration efficiency (CE) was calculated to be 510 cm² C^?1. Clear change from green (neutral) to blue-violet color (oxidized) of ECD is demonstrated with robust cycle life. These results provide an avenue for applications of polyindole family in electrochromic devices.     

Synthesis and photovoltaic properties of a low‐band‐gap polymer consisting of alternating thiophene and benzothiadiazole derivatives for bulk‐heterojunction and dye‐sensitized solar cells

We synthesized a novel low‐band‐gap, conjugated polymer, poly[4,7‐bis(3′,3′‐diheptyl‐3,4‐propylenedioxythienyl)‐2,1,3‐benzothiadiazole] [poly(heptyl₄‐PTBT)], consisting of alternating electron‐rich, diheptyl‐substituted propylene dioxythiophene and electron‐deficient 2,1,3‐benzothiadiazole units, and its photovoltaic properties were investigated. A thin film of poly(heptyl₄‐PTBT) exhibited an optical band gap of 1.55 eV. A bulk‐heterojunction solar cell with indium tin oxide/poly(3,4‐ethylenedioxythiophene)/poly(heptyl₄‐PTBT): methanofullerene [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) (1:4)/LiF/Al was fabricated with poly(heptyl₄‐PTBT) as an electron donor and PCBM as an electron acceptor and showed an open‐circuit voltage, short‐circuit current density, and power conversion efficiency of 0.37 V, 3.15 mA/cm², and 0.35% under air mass 1.5 (AM1.5G) illumination (100 mW/cm²), respectively. A solid‐state, dye‐sensitized solar cell with a SnO₂:F/TiO₂/N3 dye/poly(heptyl₄‐PTBT)/Pt device was fabricated with poly(heptyl₄‐PTBT) as a hole‐transport material. This device exhibited a high power conversion efficiency of 3.1%, which is the highest power conversion efficiency value with hole‐transport materials in dye‐sensitized solar cells to date. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1394–1402, 2007     

Degradation behavior of stereoregular cis–transoidal poly(phenylacetylene)s

The stability of poly(phenylacetylene)s in solution was systematically studied. Cis–transoidal poly(phenylacetylene) prepared with a Rh catalyst readily underwent autoxidative degradation into oligomers, whereas a W‐based polymer with a trans‐rich geometrical structure degraded slowly under similar conditions. The degradation of W‐based poly(phenylacetylene) was independent of the solvents, whereas the degradation of the cis–transoidal material strongly depended on the solvents, and very rapid degradation was observed in toluene and CHCl₃. A reduction in the degradation rate in the absence of oxygen and the appearance of carbonyl groups in an IR spectrum and aldehyde protons in a ¹H NMR spectrum of the resulting oligomers indicated the direct participation of oxygen in the degradation where light was supposed to assist the degradation by producing radicals on the main chain. The cis content of cis–transoidal poly(phenylacetylene) was unchanged during the degradation, unlike for the acid‐catalyzed decomposition, in which the cis content decreased linearly as the molecular weight decreased. Ring‐substituted poly(phenylacetylene)s degraded slowly compared with poly(phenylacetylene), regardless of the kind of substituent, which suggests that steric factors affected the degradation rate. The use of radical scavengers such as 2,2,6,6‐tetramethylpiperidine‐1‐oxyl and diphenylpicrylhydrazil suppressed the decomposition. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3130–3136, 2001     

Evaluation of piezoelectric PVDF polymers for use in space environments. II. Effects of atomic oxygen and vacuum UV exposure

The effects of atomic oxygen (AO) and vacuum UV radiation simulating low Earth orbit conditions on two commercially available piezoelectric polymer films, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene) P(VDF‐TrFE), have been studied. Surface erosion and pattern development are significant for both polymers. Erosion yields were determined as 2.8 × 10^?24 cm³/atom for PVDF and 2.5 × 10^?24 cm³/atom for P(VDF‐TrFE). The piezoelectric properties of the residual material of both polymers were largely unchanged after exposure, although a slight shift in the Curie transition of the P(VDF‐TrFE) was observed. A lightly cross‐linked network was formed in the copolymer presumably because of penetrating vacuum ultraviolet (VUV) radiation, while the homopolymer remained uncross‐linked. These differences were attributed to varying degrees of crystallinity and potentially greater absorption, and hence damage, of VUV radiation in P(VDF‐TrFE) compared with PVDF. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2503–2513, 2005     

Efficient Blue‐Colored Solid‐State Dye‐Sensitized Solar Cells: Enhanced Charge Collection by Using an in Situ Photoelectrochemically Generated Conducting Polymer Hole Conductor

A high power conversion efficiency (PCE) of 5.5 % was achieved by efficiently incorporating a diketopyrrolopyrrole‐based dye with a conducting polymer poly(3,4‐ethylenediothiophene) (PEDOT) hole‐transporting material (HTM) that was formed in situ, compared with a PCE of 2.9 % for small molecular spiro‐OMeTAD‐based solid‐state dye solar cells (sDSCs). The high PCE for PEDOT‐based sDSCs is mainly attributed to the significantly enhanced charge‐collection efficiency, as a result of the three‐order‐of‐magnitude higher hole conductivity (0.53 S cm^?1) compared with that of the widely used low molecular weight HTM spiro‐OMeTAD (3.5×10^?4 S cm^?1).     

A Selective Film Based on Poly(3‐octylthiophene) Doped with Dihydroxyanthraquinone Sulfonate

A stable film of poly(3‐octylthiophene)–dihydroxyanthraquinone sulfonate has been synthesized electrochemically in non‐aqueous solution. The incorporation of dihydroxyanthraquinone sulfonate as an anionic complexing ligand into poly(3‐octylthiophene) film during electropolymerization was achieved and copper ions were accumulated by reduction on the electrode surface. The presence of dihydroxyanthraquinone sulfonate during the electrochemical polymerization of 3‐octylthiophene is shown to impact the sensitivity and the stability of the organic conducting film electrode response. The electroanalysis of copper(II) ions using conducting polymer electrode was achieved by differential pulse anodic stripping voltammetry with remarkable selectivity. The analytical performance was evaluated and linear calibration graphs were obtained in the concentration range of 50–400 ng mL^?1 copper(II) ion for 240 seconds accumulation time and the limit of detection was found to be 7.8 ng mL^?1. To check the selectivity of the proposed stripping voltammetric method for copper(II) ion, various metal ions as potential interferents were tested. The developed method was applied to copper(II) determination in certified reference material, NWRI‐TMDA‐61, trace elements in fortified water.     

Dopamine Electroanalysis Using Electrochemical Biosensors Prepared by a Sinusoidal Voltages Method

A biocomposite material of tyrosinase and poly(3,4‐ethylenedioxythiophene) was electrodeposited onto gold (Au) disk microelectrode arrays and Au interdigitated microband electrode arrays (IDEs) by using a combination of sinusoidal voltages and microgravimetric method to construct amperometric biosensors for dopamine (DA). The main advantage of this new strategy consists in a reliable enzyme immobilization and in additional information related to the electropolymerization process. The determination of DA was successfully achieved in pharmaceutical formulations. The best analytical performances, in terms of the lowest limit of detection of 6×10^?7 M DA and highest recovery and stability, were obtained for IDEs based biosensor.     

ESR and spin trapping of free radicals produced in poly U and poly A using the boron-neutron capture reaction

Powdered samples of poly U and poly A containing sodium tetraborate and controls without tetraborate were irradiated at room temperature with thermal neutrons. Radical formation occurred only in the samples containing tetraborate. Thermal neutrons interact with ¹⁰B (10% naturally occurring in tetraborate) via the boron-neutron capture reaction. This reaction generates α particles and ⁷Li ions with mean kinetic energies of 1.48 and 0.85 MeV, respectively. The identification and location of the free radicals produced by the interaction of these particles with poly U and poly A, was determined by ESR and spin trapping using the spin trap 2-methyl-2-nitrosopropane (MNP). Following dissolution of irradiated poly U in an MNP solution, the spin trapped poly U was hydrolyzed with base (NaOH, pH 12.6). On readjusting the pH to pH 7.5 the spin adduct ESR spectrum showed that in poly U, radical formation occurs at the C(6) carbon of the uracil residues. For poly A the solid state ESR spectrum suggests that radicals are formed at the N(3) and/or N(7) nitrogens and at the C(4) and/or C(5) carbons. However, only the C(5) carbon-centered radicals were spin trapped. In addition, the results for poly A indicate that sugar-phosphate backbone is disrupted by the α particles and ⁷Li ions. The nature of this interactions is still unclear.     

An ionic liquid-based sensor for diclofenac determination in water

This paper details a miniaturised, solid state ion-selective electrode selective for diclofenac. The sensor comprises a novel ionic liquid electroactive material – an imidazolium–diclofenac ion associate. The ion associate is present in a plasticised poly(vinyl chloride) (PVC) membrane on planar carbon electrodes, with an intermediate poly(3,4-ethylenedioxythiophene) layer. The sensitivity and selectivity of the sensor were determined using chronopotentiometric methods. In response to diclofenac, a slope of ?53.3 ± 3.6 mV/dec was observed. A limit of detection of 2.90 × 10^?3 g L^?1 is reported, with a linear range of 3.18 × 10^?3 g L^?1 to 3.18 g L^?1. The sensors show good selectivity towards diclofenac against pertinent interferent molecules, with a response time of <15 s.