Truly solid state electrochromic devices constructed from polymeric ionic liquids as solid electrolytes and electrodes formulated by vapor phase polymerization of 3,4-ethylenedioxythiophene

Using polymeric ionic liquids, namely poly[1-(2-(2-(2-(methacryloyloxy)ethoxy)ethoxy)ethyl)-3-methylimidazolium]bis(trifluoromethylsulfonyl)imide or tetracyanoborate, and poly(3,4-ethylenedioxythiophene) (PEDOT) as an ion conductor and electrodes, respectively, the all-polymer-based thin-film symmetrical electrochromic devices (ECDs) have been constructed and tested. The proposed architecture serves as a prove of concept that polymeric ionic liquids (PILs) can be themselves used as solid electrolytes thus avoiding any electrolyte leakage since the ionic liquid species are grafted on the polymer backbone. Three different methods for the synthesis of PEDOT electrode films, including two new approaches consisted in vapor phase polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of ionic monomer and poly(ethylene glycol)(di)methacrylates, have been investigated. Two oxidants, Fe[(CF₃SO₂)₂N]₃ and Fe[(CN)₄B]₃, bearing the same anions as PILs were prepared for the first time and utilized in the vapor phase polymerization of EDOT. It was found that the more compact structure and the highest conductivity are achieved for PEDOT electrodes prepared by vapor phase polymerization of EDOT in the presence of ionic monomer and poly(ethylene glycol)(di)methacrylates, followed by radical polymerization of the latters. The simplicity of ECDs assembly, their fast switching times (3–5 s), high coloration efficiency (up to 430 cm²/C), satisfactory optical contrast (up to 28.5%), absence of any liquids and good performance in air and in vacuum were found among the advantages of the proposed technology.     

Composite nanofibers of conducting polymers and hydrophobic insulating polymers: Preparation and sensing applications

Various conducting polymer/hydrophobic insulating polymer (CP/HIP) composite nanofibers have been prepared by electrospinning and vapor deposition polymerization (VDP) with benzoyl peroxide (BPO) as oxidant. BPO is soluble in N,N-dimethylformamide (DMF) and can form homogenous solutions with hydrophobic polymers such as poly(methyl methacrylate) (PMMA) and polystyrene (PS). High-quality nanofibers of PMMA or PS containing a certain amount of BPO were produced by electrospinning and used as the templates for VDP of pyrrole, 3,4-ethylenedioxythiophene (EDOT), and aniline. The non-woven mats of the resulting CP/HIP composite fibers can be used as the high-sensitive sensing elements of gas sensors. A gas senor based on polypyrrole (PPy)/PMMA composite fibers was fabricated for sensing ammonia or chloroform vapor, and exhibited greatly improved performances comparing with those of the device based on a PPy flat film.     

Comparison of the thermally stable conducting polymers PEDOT, PANi, and PPy using sulfonated poly(imide) templates

We showed that it is possible to use sulfonated poly(amic acid)s (SPAA) to template polymerize 3,4-ethylenedioxythiophene (EDOT) to PEDOT, resulting in an aqueous dispersion of conducting polymer. This study compares PEDOT with poly(aniline) (PANi) and poly(pyrrole) PPy using the same and another, more rigid, poly(amic acid) template. A variety of system parameters, including reaction time, conductivity, and overall thermal stability, were noted to change systematically depending on the systems chosen. PANi-SPAA takes less than one tenth of the reaction time of PEDOT-SPAA (12 h versus 7 days), and results in higher conductivities at room temperature (ca. 10 S/cm). However, it is not as thermally stable as the PEDOT-SPAA system; conductivity is not measureable after annealing at 300 °C. PPy-SPAA was found to be more thermally stable than PANi-SPAA (less mass lost at 300 °C), but it was still more conductive than un-doped PEDOT-SPAA by a factor of 1000 (ca. 1.0 S/cm).     

Synthesis and characterization of conducting and non-conducting polymers of sodium 2,4,6-trichlorophenolate by microwave initiation

A novel synthesis of poly(dichlorophenylene oxide) and a conducting polymer were achieved simultaneously from 2,4,6-trichlorophenol in a very short time, using microwave energy. The characterizations of poly(dichlorophenylene oxide) and the conducting polymer were performed by DSC, TGA, elemental analysis, FTIR, ¹H and ¹³C NMR, SEM, MS and X-ray diffraction spectrometer analyses. The combined molecular weight of the polymer, 1.8×10⁴, was determined by using viscometry measurement. Poly(dichlorophenylene oxide) displaces selectivity in the favor of mainly 1,2-addition structure. The optimum conditions for the polymer and the conducting polymer synthesis were 70 W for 5 min and 100 W for 1 min, respectively. The direct synthesis of highly conducting polymer, with the conductivity of 0.3 S cm⁻² were achieved in the absence of applied doping process in a very short time sequence. Conductivity-temperature relation was examined for the conducting polymer.     

Mechanism of the droplet formation and stabilization in the aqueous two‐phase polymerization of acrylamide

Aqueous two‐phase polymerization of acrylamide has been carried out in an aqueous solution of poly(ethylene glycol) initiated by ammonium persulfate. The chemical composition of the product was characterized by FTIR, and the droplet size distribution in the initial stage of the polymerization was followed by dynamic light scattering. On the basis of the evolution of polyacrylamide aqueous droplets size distribution and morphology at every stage, a new mechanism of droplet formation was proposed. The experimental phenomenon that the small droplets always existed in the process of polymerization and some irregular shape droplets were formed in the product of aqueous two phase polymerization could be successfully explained by the new mechanism. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Simultaneous novel synthesis of conducting and non-conducting halogenated polymers by electroinitiation of (2,4,6-trichloro- or 2,6-dichlorophenolato)Ni(II) complexes

NiL₂(Ph)₂·xH₂O [L=3,5-dimethylpyrazole or N-methyl imidazole; Ph=DCP or TCP; x=0, 1 or 3] complexes were synthesised and characterised by analytical and spectroscopic methods using elemental analysis and FTIR. The electrochemical behavior of the complexes was studied by cyclic voltammetry in tetrabutylammoniumtetrafluoroborate-N,N-dimethylformamide electrolyte-solvent couple. Cyclic voltammogram of the complexes displayed two-step oxidation processes under the nitrogen gas atmosphere. The polymerization of the complexes was accomplished in the same solvent-electrolyte couple by the constant potential electrolysis of NiL₂(Ph)₂·xH₂O, synthesizing the poly(di- or monochlorophenylene oxide)s via free radical mechanism. The simultaneous polymerization of non-conducting polymer and conducting polymer (the conductivity of 0.7 S cm⁻²) were achieved by electroinitiated polymerization of Ni(DMPz)₂(TCP)₂. The structural analysis of the polymers were performed using FTIR, ¹H NMR and ¹³C NMR spectroscopic techniques and DSC for the thermal analysis. The kinetics of the polymerization was followed by in situ UV-vis spectrophotometer during the electrolysis. The low temperature ESR spectrum of the electrolysis solution also confirmed the formation of phenol radical (g=2.0028). One electron oxidation process of NiL₂(DCP)₂·xH₂O produces a new Ni(II) complex, Ni(L-L)(DCP)₂(S) by the rapid decomposition of Ni^IIIL₂(DCP)₂ into a ligand radical producing a singlet with the g value of 2.0015. Second electron oxidation process generates oligemers, which could not be isolated from the electrolyte solution.     

Enzymatic oxidation of alkoxyanilines for preparation of conducting polymers

A biomimetic route for synthesis of a conducting molecular complex between polyalkoxyanilines and a polyelectrolyte, poly (sodium 4‐styrenesulfonate) (SPS) is presented. Horseradish peroxidase (HRP) was used to catalyze the polymerization of alkoxyanilines. A few of water‐soluble ring‐substituted polyalkoxyanilines have been enzymatically synthesized with variation of groups, such as ortho‐methoxy, meta‐methoxy, ortho‐ethoxy, and meta‐ethoxy to form polyalkoxyanilines/SPS complexes. The presence of alkoxy substituents affects the polymerization reactions. These enzymatic oxidation reactions occur in a different potential range to that observed for the chemical polymerization. Similar electrochemical and optical properties were obtained for every pair of ortho‐ and meta‐alkoxy substituted polyanilines. For comparing, polyalkoxyanilines were also prepared by chemical polymerization in the presence of SPS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 103: 3724–3729, 2007     

Preparation of high‐molecular‐weight poly(L‐lactic acid)‐based polymers through direct condensation polymerization in bulk state

Poly(L ‐lactic acid‐co‐succinic acid‐co‐1,4‐butanediol) (PLASB) was synthesized by a direct condensation copolymerization of L ‐lactic acid, succinic acid (SA), and 1,4‐butanediol (BD) in bulk state using titanium(IV) butoxide (TNBT) as a catalyst. Weight average molecular weight (M_w) of PLASB increased from 3.5 × 10⁴ to 2.1 × 10⁵ as the content of SA and BD went up from 0.01 to 0.5 mol/100 mol of L ‐lactic acid (LA). PLASB having M_w in the range from 1.8 × 10⁵ to 2.1 × 10⁵ showed tensile properties comparable to those of commercially available poly(L ‐lactic acid) (PLLA). In sharp contrast, homopolymerization of LA in bulk state produced PLLA with M_w as low as 4.1 × 10⁴, and it was too brittle to prepare specimens for the tensile tests. M_w of PLASB synthesized by using titanium(IV)‐2‐ethyl(hexoxide), indium acetate, indium hydroxide, antimony acetate, antimony trioxide, dibutyl tin oxide, and stannous‐2‐ethyl 1‐hexanoate was compared with that of PLASB obtained by TNBT. Ethylene glycol oligomers with different chain length were added to LA/SA in place of BD to investigate effect of chain length of ethylene glycol oligomers on the M_w of the resulting copolymers. Biodegradability of PLASB was analyzed by using the modified Sturm test. Toxicity of PLASB was evaluated by counting viable cell number of mouse fibroblast cells that had been in contact with PLASB discs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 466–472, 2006     

Poly(ethylene glycol) as a ‘green solvent’ for the RAFT polymerization of methyl methacrylate

We demonstrate the use of a range of poly(ethylene glycol)s (PEGs) to control the polymerization of methyl methacrylate (MMA) using reversible addition-fragmentation chain transfer (RAFT) polymerization. The use of PEG as the solvent (M_n = 4600 g mol⁻¹) resulted in an increase in the rate of the reaction over that of other solvents by a factor of 5 at 60 °C, allowing MMA to be polymerized to high conversions with a DP of 100 much more rapidly than in standard solvents, while maintaining control over the molecular weight with polydispersities as low as 1.05. Interestingly, whilst the same rate increase is seen when polymerizing to a DP of 500, PEG appears to limit the achievable molecular weight to differing degrees depending on its chain length. Advantages of using PEG include its very low toxicity and other environmentally friendly aspects of its nature that allow it to be classed as a ‘green’ solvent.     

Synthesis of water‐soluble and conducting polyaniline by growing of poly (N‐isopropylacrylamide) brushes via atom transfer radical polymerization method

Polyaniline‐graft‐Poly(N‐isopropylacrylamide) copolymers were synthesized by atom‐transfer radical polymerization (ATRP) of N‐isopropylacrylamide using polyaniline macro‐initiators. Polyaniline‐chloroacetylchloride and polyaniline‐chloropropionylchloride macroinitiators were obtained by the reaction of amine nitrogens of polyaniline with chloroacetyl chloride and 2‐choloropropionyl choloride, respectively. Both macroinitiators and graft copolymers were characterized by FT‐IR and ¹H‐NMR spectroscopy. The cyclic voltammetry (CV) and UV‐Vis spectroscopy studies showed that these copolymers are electroactive. The solubility test revealed that the polyaniline‐graft‐poly (N‐isopropylacrylamide) copolymers are water soluble or water/methanol soluble. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) images showed the growing of poly (N‐isopropylacrylamide) chains on polyaniline backbone. Investigation of thermal behavior of graft copolymers by thermal gravimetry analysis (TGA) confirmed the results obtained from AFM and SEM images. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A new polymerization method and kinetics for acrylamide: Aqueous two‐phase polymerization

The concept of aqueous two‐phase polymerization and a new polymerization method for the preparation of water‐soluble polymers are presented. The phase diagram of poly(acrylamide) (PAAm)‐poly (ethylene glycol) (PEG)‐water two‐phase system was measured by the gel permeation chromatography (GPC). The aqueous two‐phase of PAAm‐PEG‐water system can be easily formed. The critical concentration of phase separation was affected by the molecular weight of PEG. The aqueous two‐phase polymerization of acrylamide (AAm) has been successfully carried out in the presence of PEG by using ammonium persulfate (APS) as the initiator. The polymerization behaviors with varying concentration of AAm, initiator and PEG, the polymerization temperature, the molecular weight of PEG, and emulsifier types were investigated. The activation energy of aqueous two‐phase polymerization of AAm was 132.3 kJ/mol. The relationship of initial polymerization rate (R_p0) with APS and AAm concentrations was R_p0 ∝ [APS]^0.72 [AAm]^1.28. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Kinetics of radical polymerization of glycidyl methacrylate initiated by multi‐site phase transfer catalyst–potassium peroxydisulfate in two‐phase system

The kinetics of radical polymerization of glycidyl methacrylate, initiated by the free radicals formed in situ in the multi‐site phase transfer catalyst (PTC), 1,1,2,2‐tetramethyl‐1‐benzyl‐2‐n‐propylethylene‐1,2‐diammonium bromide chloride–potassium peroxydisulfate system was studied in an aqueous–organic two‐phase media at 60°C ± 1°C under inert and unstirred condition. The rate of polymerization (R_p) was determined at various concentrations of the monomer, initiator, catalyst, and volume fraction of aqueous phase. The effect of acid, ionic strength, and water‐immiscible organic solvents on the R_p was examined. The temperature dependence of the rate was studied, and activation parameters were calculated. R_p increased with an increase in the concentrations of monomer, initiator, multi‐site PTC, and increase in the polarity of solvent and temperature. The order with respect to monomer, initiator, and multi‐site PTC was found to be 0.50. A feasible free‐radical mechanism consistent with the experimental data has been proposed, and its significance was discussed. The synthesized polymer was confirmed by Fourier transform infrared spectral analysis. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In-situ QCM-D analysis reveals four distinct stages during vapour phase polymerisation of PEDOT thin films

Gaining a deeper understanding of the growth of poly(3,4-ethylenedioxythiophene) (PEDOT) films by vapour phase polymerisation (VPP) is essential for the rational design and optimization of such films. The VPP process was used to synthesise films of PEDOT on oxidant-coated substrates. Atomic force microscopy images showed that the morphology of the films changed considerably with time. Utilising a quartz crystal microbalance with dissipation measurement (QCM-D), we found that the kinetics of polymerisation and the viscoelastic properties of the films varied. The data reveal four distinct stages in film growth. Each stage produces a layer having different conductivity values, from a low of 276 S cm⁻¹ to a high of 1196 S cm⁻¹. Conductivity and electrochromic optical contrast, Δ%Tx, can thus be maximized by appropriate termination of the polymerisation reaction. Factors determining the polymerisation rate and changes in conductivity and optical performance are discussed.     

Temperature distribution effects during polymerization of methacrylate‐based monoliths

Monolithic stationary phases are becoming increasingly important in the field of liquid chromatography. Methacrylate‐based monoliths are produced via free‐radical bulk polymerization. The preparation of large‐volume monoliths is a major problem because the intensive heat released during polymerization causes distortion of the porous monolithic structure. This work presents experimental measurements of temperature distributions during polymerization in moulds of different sizes and at various experimental conditions. A mathematical model for the prediction of temporal and spatial temperature distribution during the polymerization of methacrylate‐based monolithic columns is introduced. The polymerization is described by an unsteady‐state heat conduction equation with the generation of heat related to the general kinetics of polymerization. Predictions from the mathematical model are in good agreement with the experimental measurements at different experimental conditions. A method for construction of large‐volume monolithic columns is presented and an attempt is made to adopt the developed mathematical model in annular geometry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2326–2334, 2003     

Electrically-assisted chemical vapor polymerization: A novel method for in situ polymerization of pyrrole

This article offers a fast and innovative process for carrying out in situ polymerization of pyrrole onto a polyester fabric. This process is based on electrically-assisted chemical vapor polymerization that takes around 180 s to produce an electroconductive fabric with a surface resistance of as low as 70 Ω. The ultrasonication carried out at 20 kHz frequency is quite effective in binding the polymer to the fabric. Fourier-transform infrared spectroscopy and X-ray diffraction studies confirm that the polymer formed is polypyrrole. The application of electric potential across an oxidant-enriched fabric results in polymer add-on of polypyrrole as high as 250%. The amount of polypyrrole formed and the surface resistance of the fabric are found to depend on the potential applied across the fabric. The concentrations of the oxidant and the dopant, the time of polymerization, and the rate of monomer vaporization are found to be critical in deciding the surface resistance of the fabric.     

Novel comb‐structured‐polymer‐grafted carbon black by surface‐initiated atom transfer radical polymerization and ring‐opening polymerization

Novel comb‐structured‐polymer‐grafted carbon black (CB) was synthesized with a combination of surface‐initiated atom transfer radical polymerization and ring‐opening polymerization. First, poly(2‐hydroxyethyl methacrylate) (PHEMA) was grafted onto the CB surface by surface‐initiated atom transfer radical polymerization. The prepared CB‐g‐PHEMA contained 35.6–71.8% PHEMA, with the percentage depending on the molar ratio of the reagents and the reaction temperature. Then, with PHEMA in CB‐g‐PHEMA as the macroinitiator, poly(?‐caprolactone) (PCL) was grown from the CB‐g‐PHEMA surface by ring‐opening polymerization in the presence of stannous octoate. CB‐g‐PHEMA and CB‐g‐(PHEMA‐g‐PCL) were characterized with Fourier transform infrared, ¹H‐NMR, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The resultant grafted CB had a shell of PHEMA‐g‐PCL. On the whole, the CB nanoparticles were oriented in dendritic lamellae formed by these shells. This hopefully will result in applications in gas sensor materials and nanoparticle patterns. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Particle growth modeling of gas phase polymerization of butadiene

Butadiene polymerization in the gas phase is modeled by a polymeric multilayer model. Intraparticle mass and heat transfer effects are studied. The effects of catalyst size and diffusivity of butadiene on the radial profile of monomer concentration in polymeric particles and on the rate of particle growth are significant. Intraparticle temperature gradients do appear to be negligible under normal reaction conditions. External boundary layer heat effects are studied for various operation conditions. The model predicts that there is no significant temperature rise of the polymeric particles, even in the case of large catalyst particles. The effect of deactivation of active sites on the rate of particle growth is also studied. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 203–212, 1997     

Molecular selectivity of tyrosine-imprinted polymers prepared by seed swelling and suspension polymerization

Tyrosine-imprinted microspheres have been prepared in an aqueous system by seed swelling and suspension polymerization, using trimethylolpropane trimethacrylate (TRIM), acrylamide (AM) as well as methacrylic acid (MAA), linear polystyrene and toluene as crosslinker, functional monomers, seeds and porogens, respectively. The size distribution proved to be greatly influenced by the ratio of water:TRIM (W/T) and the concentration of dispersant. When W/T was 46:1 (v/v), 4.6% (by mass) of poly(vinyl alcohol) (PVA) was used as dispersant, the molar ratios of tyrosine, MAA, AM and TRIM were 1:8:8:17, the polymer beads had the better size monodispersity, and the average size was 135 µm, while the sizes of the pores on the beads surfaces ranged from 1.25 µm to 9.0 µm. The adsorption behaviour and molecular selectivity of the beads were analysed using liquid chromatography; the results showed that the adsorption behaviour of the beads followed the rule of Langmuir, and the value of saturated absorption was 0.197 mmol g⁻¹. The tyrosine-imprinted polymers exhibited an inherent selectivity for tyrosine; when phenylalanine was used as the competing molecule the separation factor α was up to 1.91. However, the control polymers did not have this special molecule-selection capability, and the relative separation factor β was about 1.82 compared with the imprinted polymers. © 2002 Society of Chemical Industry     

Selective solid‐phase extraction of naphazoline using imprinted polymers as matrix prepared by precipitation polymerization

The molecularly imprinted polymers (MIP) for drug naphazoline (NAZ) have been synthesized by precipitation polymerization. The effect of the dispersive solvents dichloromethane (DCM), acetonitrile (ACN), and Methanol (MeOH) on particle size and morphology of MIP (P1, P2, and P3) was investigated by scanning electron microscopy (SEM). The selectivity of P1, compared with nonimprinted polymer (NIP), C₈ and C₁₈ were evaluated via static adsorption using UV spectrophotometer. The result showed that the bond amount of P1 for NAZ was significantly higher than other sorbents. The P1 were applied as a solid‐phase extraction (SPE) stationary phase to extract the NAZ from nasal drops and recoveries of more than 89% (relative standard deviations, RSD <5%) were obtained by high performance liquid chromatograph (HPLC) analyses. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010