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1.
Poly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles were synthesized via chemical oxidation polymerization using 3,4‐ethylenedioxythiophene as the starting monomer and ammonium peroxydisulfate (APS) as the oxidant. The effects of APS concentration, surfactant concentration and type of surfactant, namely dodecylbenzenesulfonic acid and sodium dodecylsulfate, were investigated. Distinct particle shapes were obtained: irregular, raspberry agglomerate, coralliform, orange‐peel, globular and plum shapes. The particle sizes and the electrical conductivity are in the ranges 60 to 900 nm and <1 to 153 S cm?1, respectively, depending on the polymerization conditions. PEDOT synthesis in the absence of a surfactant yields a smaller particle size because a larger amount of initiator induces lower molecular weights and smaller PEDOT particles. The smaller PEDOT particles correspond to higher electrical conductivity because of the larger surface areas for electron transfer and a smaller amount of obstructing surfactant aliphatic segments. Moreover, particle size and shape can be varied, depending on surfactant type and concentration which dictate the micellar shapes in the polymerization reaction. This work is focused on the tailor‐made PEDOT shape and property relationship under synthesis conditions where several shapes have not been previously seen. © 2013 Society of Chemical Industry  相似文献   

2.
Poly(3,4‐ethylenedioxythiophene) (PEDOT) doped with a series of anionic polysaccharides such as carboxymethyl cellulose, sodium hyaluronate, xanthan gum, pectin, gellan gum were prepared by electropolymerization in aqueous solutions. Some other dopants of potassium nitrate, potassium sulfate, sodium poly(styrenesulfonate), and sodium polyacrylate were used in comparison with the anionic polysaccharides. The electrochemical properties and stability of the obtained PEDOT films were also investigated. It was found that indium tin oxide (ITO) conductive glass could be used as the working electrode of the electropolymerization of EDOT and that the dopant had a great influence on polymerization potential and overoxidation potential. These charged biomolecules of anionic polysaccharides were found to facilitate electropolymerization of EDOT instead of common doping anions as counterion. The electroactive PEDOT films doped with anionic polysaccharides showed stable electrochemical properties, good texture, and adhesion properties to the ITO conductive glass. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

3.
This article reports the synthesis of conducting ferromagnetic complex of 3,4‐ethylenedioxythiophene (EDOT) and aniline (An) containing M‐type hexagonal barium ferrite (BaFe12O19) particles using in situ emulsion polymerization and electrochemical oxidative polymerization. Magnetic and conductivity studies reveal that the conducting ferromagnetic complex possesses high‐saturation magnetization (Ms) value of 29.2 emu/g and conductivity of the order of 0.256 S/cm determined through vibrating sample magnetometer and four‐probe method. Microwave measurement has shown the reflection loss (RL) of ?12.1 dB in Ku‐band that can be used as a microwave absorbing material. The polymer complex was further characterized by techniques like X‐ray diffraction, Fourier transform infrared, UV–visible, cyclic voltammetry, and thermal analysis with thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008  相似文献   

4.
A new emulsion polymerization process, in which water acted as the dispersed phase and a mixture of methyl methacrylate (MMA) and cyclohexane acted as the continuous phase, was applied to the preparation of a poly(methyl methacrylate) (PMMA) resin. The primary (latex) particles were formed in the early stage of polymerization and coagulated as the polymerization conversion increased. Scanning electron micrographs showed that the final PMMA particles were porous and composed of loosely aggregated primary particles. The porosity characterized by cold di(2‐ethylhexyl) phthalate absorption increased as the water/oil and cyclohexane/MMA mass ratios increased. The PMMA primary particles were smaller than the primary particles in the PMMA resin prepared by suspension polymerization in the presence of cyclohexane. Because of the phase composition of the reaction system, the solubility of PMMA in a mixture of cyclohexane and MMA, and the particle morphology of PMMA, a particle formation mechanism, including the formation, growth, and coagulation of primary particles in dispersed water droplets, was proposed. The primary particles formed mainly through a homogeneous nucleation mechanism and increased in size as MMA diffused from the oil phase to the water phase to the primary particles. The coagulation of the primary particles occurred because of the lower colloidal stability and the space limitations of the primary particles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1905–1911, 2004  相似文献   

5.
Films of poly(3,4‐ethylenedioxythiophene) were prepared with single and multiple electropolymerization steps, where the numbers of polymerization steps (n's) were 3, 5, and 7, with identical experimental conditions and total polymerization times (τ's). The electroactivity of the films prepared with multiple steps remained almost unaltered when n increased, with the ability of the films to store charge with n > 3 being smaller than that of the films with similar thicknesses but derived from a single electrodeposition step. In contrast, the stability of the films produced with n polymerization steps was significantly higher than that of the films derived from a single step with the same τ, with the difference between the two systems increasing with n, that is, τ used to yield the films. On the other hand, although the morphological and topological characteristics of the surface and the electrical conductivity were affected by the procedure used to produce the films, the organization of the polymer molecules in the crystalline phase, the thermal stability, and the electronic properties (ionization potential, electron affinity, and lowest π–π* transition energy) were practically identical in both cases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

6.
In this study, we prepared poly(3,4‐ethylenedioxythiophene) (PEDOT) via the chemical oxidation of the 3,4‐ethylenedioxythiophene monomer in a system consisting of miscible binary organic solvents, that is, acetonitrile (CH3CN) and chloroform (CHCl3). This successful technique was then used to synthesize a poly(3,4‐ethylenedioxythiophene) (PEDOT)/silver (Ag) nanocomposite as well. In this facile and efficient technique, a higher solubility of the oxidizing reagent, which originated from a relative enhancement in the polarity of the reaction medium, led to significant changes in the optical and thermal behaviors of the resulting products. To investigate the degree of validity of the technique applied, a pure sample of PEDOT (PEDOT I) was also synthesized with CHCl3 alone, and this was then compared with a sample prepared in CH3CN/CHCl3 binary solvents (PEDOT II). To prepare the PEDOT/Ag nanocomposite, first the PEDOT synthesized in binary solvents was thoroughly dissolved in a dimethyl sulfoxide solvent. Next, Ag nanopowder was uniformly dispersed in the previous solution of PEDOT with sonication. The PEDOT/Ag nanocomposite was then precipitated through the addition of a methanol nonsolvent. The approximate size of nano‐Ag within the polymer matrix was found to be about 40 nm. Scanning electron microscopy images of the pure PEDOT II and PEDOT/Ag nanocomposite exhibited an agglomerated sponge and nanospherical homogeneity, respectively. In comparison with PEDOT I, considerable redshifts in the ultraviolet–visible absorption spectra of the pure PEDOT II and PEDOT/Ag nanocomposite were observed. In addition, the thermostability order was found to be PEDOT/Ag > PEDOT II > PEDOT I at all temperatures above 300°C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2707–2712, 2013  相似文献   

7.
Suspension‐emulsion combined polymerization process, in which methyl methacrylate (MMA) emulsion polymerization constituents (EPC) were drop wise added to styrene (St) suspension polymerization system, was applied to prepare polystyrene/poly(methyl methacrylate) (PS/PMMA) composite particles. The influences of the feeding condition and the composition of EPC on the particle feature of the resulting composite polymer particles were investigated. It was found that PS/PMMA core‐shell composite particles with a narrow particle size distribution and a great size would be formed when the EPC was added at the viscous energy dominated particle formation stage of St suspension polymerization with a suitable feeding rate, whereas St‐MMA copolymer particles or PS/PMMA composite particles with imperfect core‐shell structure would be formed when the EPC was added at the earlier or later stage of St suspension polymerization, respectively. It was also showed that the EPC composition affected the composite particles formation process. The individual latex particles would exist in the final product when the concentrations of MMA monomer, sodium dodecyl sulfate emulsifier, and potassium persulfate initiator were great in the EPC. Considering the feature of St suspension polymerization and the morphology of PS/PMMA composite particles, the formation mechanism of PS/PMMA particles with core‐shell structure was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

8.
Poly(2‐chloromethyl‐2,3‐dihydrothieno[3,4‐b][1,4]dioxine), a chloromethyl functionalized poly(3,4‐ethylenedioxythiophene) derivative (PEDOT‐MeCl), was synthesized electrochemically via the potentiostatic polymerization of its monomer in dichloromethane solution containing suitable tetrabutylammonium tetrafluoroborate, then it was used for the characterization of film properties and the fabrication of electrochemical sensor. The properties of the resulting PEDOT‐MeCl film were characterized by different methods such as cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared and ultraviolet–visible techniques, scanning electron microscope, and thermogravimetric analysis. The PEDOT‐MeCl film displayed a good reversible redox activity, remarkable capacitance properties, good thermal stability, rough, and porous structure, especially fluorescent spectra indicated that PEDOT‐MeCl was a blue‐emitter with maximum emission centered at 396 and 398 nm. Finally, the PEDOT‐MeCl film was employed for the fabrication of the sensing electrode, and dopamine was chosen as a model analyte for the application of the electrochemical sensor. Results indicated that the PEDOT‐MeCl film as sensing interface was feasible, and studies of these film properties were very beneficial for studying properties and applications of other poly(3,4‐ethylenedioxythiophene) derivative films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2660–2670, 2013  相似文献   

9.
The chemical oxidative copolymerization of 3,4‐ethylenedithiathiophene (EDTT) with 3,4‐ethylenedioxythiophene (EDOT) and 2′‐hydroxymethyl‐3,4‐ethylenedioxythiophene in a poly(styrene sulfonic acid) aqueous solution was successfully carried out to form stable, dark blue colloidal dispersions in water. Coating these dispersions onto polypropylene substrates led to the formation of free‐standing copolymer films. The mechanical, electrical, and thermoelectrical properties of these films were investigated; the films showed superior properties in comparison with those of poly(3,4‐ethylenedithiathiophene) (PEDTT)/poly(styrene sulfonate) (PSS). The copolymer film based on EDTT and EDOT achieved a high electrical conductivity (8.2 × 10?2 S cm?1) at 298 K; this could be improved about 10 times through the addition of dimethyl sulfoxide (DMSO) or DMSO/isopropyl alcohol into the polymer dispersion with almost constant Seebeck coefficients of about 9 μV K?1. On the contrary, these additives had almost no effect on the conductivity of PEDTT/PSS. The structure and morphology of the polymer films were studied by X‐ray diffraction and SEM analyses. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

10.
The effect of surfactant (sodium dodecyl sulfate) concentration on particle size, molar masses, glass transition, and tacticity of poly(methyl methacrylate) (PMMA) nanoparticles synthesized by semicontinuous heterophase polymerization under monomer‐starved condition at constant monomer feeding rate is reported. Starved conditions are confirmed by the low amount of residual monomer throughout the reaction and by the fact that the instantaneous polymerization rate is similar to the feeding rate of monomer. Under these conditions, polymer particles in the nanometer range (20–30 nm) were obtained with narrow size distribution (1.07 < Dw/Dn < 1.18), depending of surfactant concentration. Final particle size diminishes as the surfactant concentration is increased. Glass transition temperatures and syndiotactic content (54%–59%) of the produced polymers are substantially higher than those reported for commercial and bulk‐made PMMA. Molar masses are much lower than those expected from termination by chain transfer to monomer, which is the typical termination mechanism in 0–1 emulsion and microemulsion polymerization of this monomer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
In this study, the effect of solvents on the morphology and conductivity of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) nanofibers is investigated. Conductive PEDOT:PSS nanofibers are electrospun by dissolving a fiber‐forming polymer, polyvinyl alcohol, in an aqueous dispersion of PEDOT:PSS. The conductivity of PEDOT:PSS nanofibers is enhanced 15‐fold by addition of DMSO and almost 30‐fold by addition of ethylene glycol to the spinning dopes. This improvement is attributed to the change in the conformation of the PEDOT chains from the coiled benzoid to the extended coil quinoid structure as confirmed by Raman spectroscopy, X‐ray diffraction, and differential scanning calorimetry. Scanning electron microscopy images show that less beady and more uniform fiber morphology could be obtained by incorporation of ethylene glycol in the spinning dopes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40305.  相似文献   

12.
The high water solubility of vinyl acetate (VAc) monomer increases the need for a good initiator system to speed up the polymerization and remove unreacted monomers. Ultrasonic energy can be used to initiate VAc redox emulsion polymerization in the absence of an inert gas and with sodium dodecyl sulfate as a surfactant. Combining ultrasonic energy and a redox initiator at the ambient temperature leads to a higher conversion and higher rate of polymer production in comparison with just using a redox initiator. Ultrasonic energy plays an important role in synthesizing and controlling the polymer structure. The particle size distribution is an important variable in the formulation of latex paint. Ultrasonic energy has an effect on the particle size distribution and average molecular weight of VAc polymer. The particle size increases with an increase in the monomer conversion for ultrasonic polymerization, whereas the particle size stays constant with the monomer conversion for redox polymerization. An ultrasonic polymer has a broader particle size distribution than a redox polymer. The average molecular weight of poly(vinyl acetate) falls with an increase in the sonication time, whereas it increases with time for a redox polymer. Ultrasonic energy also produces a stable, milky white, opaque latex. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 812–817, 2005  相似文献   

13.
Conductive polymer particles, polyaniline (PANI)‐coated poly(methyl methacrylate–butyl acrylate–acrylic acid) [P(MMA–BA–AA)] nanoparticles, were prepared. The P(MMA–BA–AA)/PANI core–shell complex particles were synthesized with a two‐step miniemulsion polymerization method with P(MMA–BA–AA) as the core and PANI as the shell. The first step was to prepare the P(MMA–BA–AA) latex particles as the core via miniemulsion polymerization and then to prepare the P(MMA–BA–AA)/PANI core–shell particles. The aniline monomer was added to the mixture of water and core nanoparticles. The aniline monomer could be attracted near the outer surface of the core particles. The polymerization of aniline was started under the action of ammonium persulfate (APS). The final product was the desired core–shell nanoparticles. The morphology of the P(MMA–BA–AA) and P(MMA–BA–AA)/PANI particles was characterized with transmission electron microscopy. The core–shell structure of the P(MMA–BA–AA)/PANI composites was further determined by Fourier transform spectroscopy and ultraviolet–visible measurements. The conductive flakes made from the core–shell latexes were prepared, and the electrical conductivities of the flakes were studied. The highest conductivity of the P(MMA–BA–AA)/PANI pellets was 2.05 S/cm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

14.
PMMA nanoparticles with highly mono‐dispersed size distribution were prepared using the RAFT living radical emulsion polymerization technique. A novel sur‐iniferter for the RAFT reaction, DTBA, was synthesized and its chemical structure was identified using several spectroscopic techniques. The relationship between the particle size and the molecular weight of the polymer was investigated measuring the rate of growth of each during formation of particles, and was well explained by the simple random flight molecular conformation model. The particle size increased up to a certain value with decreasing sur‐iniferter concentration and then leveled off, because the surface charge density of the growing particles was not high enough to stabilize the particles in aqueous medium above that value. The core‐shell type di‐block copolymer nanoparticles were also successfully prepared via RAFT reaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

15.
A high cycling stability material and an additive manufacturing method are reported for the fabrication of solid electrochromic devices. The poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)/multi‐walled carbon nanotube (PEDOT:PSS/MWCNT) nanocomposites were synthesized via in situ polymerization. A carboxymethyl cellulose gel was used as the ink vehicle for screen printing. The electrochromic (EC) performance of films patterned by screen printing was also examined. The results of characterization indicate that strong interfacial interactions occurred between PEDOT:PSS and the MWCNTs and the MWCNTs formed a network in these conducting polymers film, so the composite was more conductive than pure PEDOT:PSS. Devices containing PEDOT:PSS/MWCNTs were more stable after 1000 cycles, exhibited higher rate of ion exchange and faster increases in current. The composite containing 0.3 wt % MWCNTs also had a 23% higher color contrast (ΔE*) than pure PEDOT:PSS at 2.5 V applied voltages. The EC inks with well printability not only can be used to print large area films, but also can print fine lines and pixel‐type dots in displays. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45943.  相似文献   

16.
Poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT–PSS) was blended with poly(vinyl alcohol) (PVA) to form 0, 10, 20, 30, 40, and 50 vol % PEDOT–PSS/PVA solutions, and their freestanding films were prepared with a simple and cost‐effective solution casting technique at 27 °C in the absence of additives. Field emission scanning electron microscopy images revealed changes in the cocontinuous network to a rodlike morphology in the composite films from 10 to 50 vol % PEDOT–PSS/PVA. The alternating‐current conductivity was found to obey Jonscher's power law. The obtained values of the dielectric constant at 27 °C were relatively high, and a maximum value of 6.7 × 104 at 100 Hz for 40 vol % PEDOT–PSS'/PVA was observed. The dielectric loss attained a maximum value of about 106 at 100 Hz for 40 vol % PEDOT–PSS/PVA. However, a decrease in the dielectric parameters was observed at 50 vol % PEDOT–PSS/PVA because of locally induced strain in the microstructure. The variations in polarization with respect to the applied electric field (P–E) were determined for 50, 100, and 500 Hz at 500 V for the freestanding composite films of lower concentrations up to 20 vol % PEDOT–PSS/PVA. In summary, the dielectric and P–E measurements confirmed that the electrical characteristics changed in accordance to the contribution from both resistive and capacitive sites in the PEDOT–PSS/PVA composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45079.  相似文献   

17.
Poly(3,4‐ethylenedioxythiophene) (PEDOT) was in situ polymerized on nylon 6, poly(ethylene terephthalate) (PET), and poly(trimethylene terephthalate) (PTT) fabrics using ferric p‐toluenesulfonic acid (FepTS) and ferric chloride (FeCl3) as oxidants. The effect of the organic solvents used in the polymerization bath was investigated. Prepared PEDOT/nylon 6 composite fabrics have superior electrical conductivity (0.75 S/cm, in ethanol solvent) compared to those of the other PEDOT composite fabrics. In particular, after five cycles of polymerization, the electrical conductivity of the composite fabric reached about 2 S/cm. However, the nylon 6 fabric was damaged by EDOT radical cations and the strong acidity of FepTS during the polymerization process. It was concluded that PTT fabric, which has excellent elastic recovery and acid resistance, is a suitable substrate for in situ polymerization of PEDOT, because the PEDOT/PTT composite fabric was hardly damaged during the polymerization process and its electrical conductivity is comparatively good (0.36 S/cm, in butanol solvent). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1326–1332, 2005  相似文献   

18.
Montmorillonite, organically modified by octadecylammine salt, has been adopted to successfully fabricate the exfoliated organic montmorillonite/poly(3,4‐ethyldioxythiophene) (OMMT/PEDOT) nanocomposites by in situ polymerization in aqueous media. Hydrochloric acid, 1,5‐naphthalenedisulfonic acid, and sodium benzenesulphonate have been employed to activate the polymerization of 3,4‐ethyldioxythiophene by offering active sites on the layers of montmorillonite. The resulting exfoliated nanocomposites have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, thermogravimetric analysis, and electrical conductivity measurement and showed controllable conductivity in the range of 10?7 to 10?2 S/cm and improved thermal stability compared with pure PEDOT. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

19.
Composite conductive fibers based on poly(3,4‐ethylenedioxythiophene) (PEDOT)–polystyrene sulfonic acid (PSS) blended with polyacrylonitrile (PAN) were prepared via a conventional wet‐spinning process. The influences of the PEDOT–PSS content on the electrical conductivity, thermal stability, and mechanical properties of the composite fibers were investigated. The fibers with 1.83 wt % PEDOT–PSS showed a conductivity of 5.0 S/cm. The breaking strength of the fibers was in the range 0.36–0.60 cN/dtex. The thermal stability of the PEDOT–PSS/PAN composite fibers was similar to but slightly lower than that of the pure PAN. The X‐ray diffraction results revealed that both the pure PAN and PEDOT–PSS/PAN composite fibers were amorphous in phase, and the crystallization of the latter was lower than that of the former. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

20.
This paper reports a range of effective sequential chemical processes to enhance the thermoelectric performance of conducting poly(3,4‐ethylenedioxythiophene) films doped with poly(styrene sulfonate) anions (PEDOT:PSS). The electrical conductivity of the PEDOT:PSS films was significantly increased from 0.33 to 3748 S cm?1 after a series of sequential treatments with trifluoroacetic acid (TFA) while the Seebeck coefficient and thermal conductivity were slightly reduced from 17.5 ± 1.2 to 16.0 ± 1.1 μV K?1 and 0.537 to 0.415 W m–1 K?1 for the pristine film and treated film, respectively, leading to a significant improvement in power factor up to 97.1 ± 5.4 μW m–1 K?2. More importantly, around 80% of the electrical conductivity and Seebeck coefficient was retained after 20 days for these TFA‐treated PEDOT:PSS films, revealing the potential for real thermoelectric applications. © 2019 Society of Chemical Industry  相似文献   

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