Emulsion synthesis of nanoparticles containing PEDOT using conducting polymeric surfactant: Synergy for colloid stability and intercalation doping

Poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is a widely used conductive aqueous dispersion synthesized by using emulsion polymerization method. To further enhance its solution processability and conductivity of PEDOT derivatives, we proposed to replace the nonconductive PSS with conductive poly[2‐(3thienyl)‐ethoxy‐4‐butylsulfonate] (PTEB) as surfactant for the emulsion polymerization of PEDOT. The reaction involved colloid stabilization and doping in one step, and yielded PEDOT:PTEB composite nanoparticles with high electrical conductivity. Contrary to its counterpart containing nonconductive surfactant, PEDOT: PTEB showed increasing film conductivity with increasing PTEB concentration. The result demonstrates the formation of efficient electrical conduction network formed by the fully conductive latex nanoparticles. The addition of PTEB for EDOT polymerization significantly reduced the size of composite particles, formed stable spherical particles, enhanced thermal stability, crystallinity, and conductivity of PEDOT:PTEB composite. Evidence from UV–VIS and FTIR measurement showed that strong molecular interaction between PTEB and PEDOT resulted in the doping of PEDOT chains. X‐ray analysis further demonstrated that PTEB chains were intercalated in the layered crystal structure of PEDOT. The emulsion polymerization of EDOT using conducting surfactant, PTEB demonstrated the synergistic effect of PTEB on colloid stability and intercalation doping of PEDOT during polymerization resulting in significant conductivity improvement of PEDOT composite nanoparticles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2536–2548, 2008     

Supramolecular assembly of poly(ionic liquid) nanogel driven by host‐stabilized charge transfer interaction

Poly(ionic liquid) (PIL)‐based nanogels, functionalized by naphthyl (Np), are fabricated via a facile one‐step ternary crosslinking copolymerization in selective solvent. The size of PIL nanogels can be conveniently regulated through the feed ratio of IL monomer to crosslinker. The presence of Np groups in PIL nanogel is confirmed by using ultraviolet–visible (UV–vis), Fourier transform infrared, and X‐ray photoelectron spectroscopy measurements. Through introducing cucurbit[8]uril (CB[8]) and bisviologen compound (DEDV) as the host molecule and electron acceptor, respectively, host‐stabilized charge transfer (HSCT) interaction is achieved through utilizing Np containing PIL nanogel as the building block. The studies reveal that PIL nanogels can form schistose aggregates in the scale of micrometer via HSCT interaction. The aggregates will be broken in the presence a competitive guest molecule (amantadine) and can recover by adding another host molecule (CB[7]). HSCT interaction among CB[8], DEDV and PIL nanogel is investigated by dynamic light scattering, UV–vis, and Proton nuclear magnetic resonance. Our studies thus provided an applicable strategy for constructing dynamic polymer nanoparticles through noncovalent interaction. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2251–2259     

Preparation of main‐chain imidazolium‐functionalized amphiphilic block copolymers through combination of condensation polymerization and nitroxide‐mediated free radical polymerization and their micelle study

Main‐chain imidazolium‐functionalized amphiphilic block copolymers (PIL‐b‐PS) consisting of polyionic liquid (PIL) and polystyrene (PS) blocks have been first synthesized by condensation polymerization combined with nitroxide‐mediated free radical polymerization (NMP). The di‐functional imidazolium‐based ionic liquid (IL) having both hydroxyl and ester end groups was synthesized through Michael addition between imidazole and methylacrylate (MA) and further quaternization by 2‐chloroethanol. The HTEMPO (4‐hydroxy‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy) terminated polyionic liquid (HTEMPO‐PIL) as the hydrophilic block was prepared by condensation polymerization of di‐functional imidazolium IL and HTEMPO at a certain ratio. The hydrophobic PS block was synthesized by controlled radical polymerization of styrene using HTEMPO‐PIL through NMP, resulting PIL‐b‐PS block copolymers. The structure of block copolymers obtained has been characterized and verified by FTIR, ¹H NMR, and size exclusion chromatography analyses. In addition, the morphology and size of the micelles formed by PIL‐b‐PS block copolymers in water were investigated by transmission electron microscopy and dynamic light scattering. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Initialization behavior at various target molecular weight RAFT‐mediated methyl acrylate polymerizations

In the reversible addition‐fragmentation chain transfer (RAFT) mediated polymerization of methyl acrylate, a selective reaction is observed in the early stages of the polymerization. This initialization process was earlier observed in in situ ¹H NMR spectroscopy experiments where extremely low target molar masses were chosen (around DP = 5). Here, for the first time, the presence of the initialization process is identified as the cause of an induction period under typical conditions of a RAFT‐mediated polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2500–2509, 2008     

Poly(3,4‐ethylenedioxythiophene) Derived from Poly(ionic liquid) for the Use as Hole‐Injecting Material in Organic Light‐Emitting Diodes

We report that poly(3,4‐ethylenedioxythiophene) derived from poly(ionic liquid) (PEDOT:PIL) constitutes a unique polymeric hole‐injecting material capable of improving device lifetime in organic light‐emitting diodes (OLEDs). Imidazolium‐based poly(ionic liquid)s were engineered to impart non‐acidic and non‐aqueous properties to PEDOT without compromising any other properties of PEDOT. A fluorescent OLED was fabricated using PEDOT:PIL as a hole‐injection layer and subjected to a performance evaluation test. In comparison with a control device using a conventional PEDOT‐based material, the device with PEDOT:PIL was found to achieve a significant improvement in terms of device lifetime. This improvement was attributed to a lower indium content in the PEDOT:PIL layer, which can be also interpreted as the effective protection characteristics of PEDOT:PIL for indium extraction from the electrodes.

     

Bipolar poly(p‐phenylene vinylene)s bearing electron‐donating triphenylamine or carbazole and electron‐accepting quinoxaline moieties

Two new poly(phenylene vinylene)s (PPVs) carrying electron‐donating triphenylamine or carbazole and electron‐deficient quinoxaline units were synthesized and characterized. Their properties were compared with those of PPV containing only quinoxaline unit. The two polymers showed PL maximum at 501–510 in solution and 533–540 in thin film. Because of the presence of electron donor and acceptor units they displayed strong intramolecular charge transfer (ICT) effects; hence, low‐photoluminescence quantum yields. The polymers showed reversible electrochemical reduction with electron affinity of 2.75 eV and irreversible oxidation with ionization potential of 5.10–5.24 eV. Single‐layer LED of configuration ITO/PEDOT/polymer/Al showed low turn‐on voltage at 5 V, but limited brightness of 50–60 cdm^?2. The electroluminescence maximum was voltage‐tunable varying from 500 to 542 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2367–2378, 2008     

Why does the electrical conductivity in PEDOT:PSS decrease with PSS content? A study combining thermoelectric measurements with impedance spectroscopy

We have investigated the electrical transport properties of poly(3,4‐ethylenedioxythiophen)/poly(4‐styrene‐sulfonate) (PEDOT:PSS) with PEDOT‐to‐PSS ratios from 1:1 to 1:30. By combining impedance spectroscopy with thermoelectric measurements, we are able to independently determine the variation of electrical conductivity and charge carrier density with PSS content. We find the charge carrier density to be independent of the PSS content. Using a generalized effective media theory, we show that the electrical conductivity in PEDOT:PSS can be understood as percolation between sites of highly conducting PEDOT:PSS complexes with a conductivity of 2.3 (Ωcm)^?1 in a matrix of excess PSS with a low conductivity of 10^?3 (Ω cm)^?1. In addition to the transport properties, the thermoelectric power factors and Seebeck coefficients have been determined. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Synthesis of low‐polydispersity poly(N‐ethylmethylacrylamide) by controlled radical polymerizations and their thermal phase transition behavior

Controlled radical polymerizations of N‐ethylmethylacrylamide (EMA) by atom transfer radical polymerization and reversible addition‐fragmentation chain transfer processes were investigated in detail for the first time, employing complementary characterization techniques including gel permeation chromatography, ¹H NMR spectroscopy, and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. In both cases, relatively good control of the polymerization of EMA was achieved, as revealed by the linear evolution of molecular weights with monomer conversions and the low polydispersity of poly(N‐ethylmethylacrylamide) (PEMA). The thermal phase transitions of well‐defined PEMA homopolymers with polydispersities less than 1.2 and degrees of polymerization up to 320 in aqueous solution were determined by temperature‐dependent turbidity measurements. The obtained cloud points (CPs) vary in the range of 58–68 °C, exhibiting inverse molecular weight and polymer concentration dependences. Moreover, the presence of a carboxyl group instead of an alkyl one at the PEMA chain end can elevate its CP by ～3–4 °C. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 60–69, 2008     

Partially sulfonated ethylene–vinyl alcohol copolymer as new substrate for 3,4‐ethylenedioxythiophene vapor phase polymerization

A new conducting composite polymer film is obtained by vapor phase polymerization of 3,4‐ethylenedioxythiophene (EDOT) on a biocompatible polyanion derived from the partial sulfonation (32%) of statistical ethylene vinyl alcohol copolymer (EVAL32). EVALS32 and the oxidant (iron(III) p‐toluenesulfonate, [PTS]) are contemporaneously spin coated from a methanol/water solution on glass slide. EVALS32–PTS‐coated glass slides are exposed to EDOT vapors, and the polymerization is followed by Vis–NIR spectroscopy. We observed that PEDOT slowly grows into the bulk of EVALS32 matrix. Thanks to the sulfonic groups of the polyanion acting as doping agents, a highly conjugate p‐doped EVALS32‐PEDOT composite film with a good conductivity (1.6 × 10² S cm^?1), transparency, and stability in water is obtained. The EVALS32–PEDOT film seems an ideal candidate for the preparation of organic devices to be applied in electronics, biosensor, or actuation technology. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1203–1210     

Secondary doping in poly(3,4‐ethylenedioxythiophene):Poly(4‐styrenesulfonate) thin films

The electrical and structural properties of poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) thin films deposited from aqueous dispersion using different concentrations of selected secondary dopants are studied in detail. An improvement of the electrical conductivity by three orders of magnitude is achieved for dimethyl sulfoxide, sorbitol, ethylene glycol, and N,N‐dimethylformamide, and the secondary dopant concentration dependence of the conductivity exhibits almost identical behavior for all investigated secondary dopants. Detailed analysis of the surface morphology and Raman spectra reveals no presence of the secondary dopant in fabricated films, and thus the dopants are truly causing the secondary doping effect. Although the ratio of benzenoid and quinoid vibrations in Raman spectra is unaffected by doping, the phase transition in PEDOT:PSS films owing to doping is confirmed. Further analysis of temperature‐dependent conductivity reveals 1D variable range hopping (VRH) charge transport for undoped PEDOT:PSS, whereas highly conductive doped PEDOT:PSS films exhibit 3D VRH charge transport. We demonstrate that the charge ‐ hopping dimensionality change should be a fundamental reason for the conductivity enhancement. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1139–1146     

Synthesis of polymeric ionic liquid microsphere/Pt nanoparticle hybrids for electrocatalytic oxidation of methanol and catalytic oxidation of benzyl alcohol

Herein, we present a facile approach for the synthesis of polymeric ionic liquids (PILs) microspheres for metal scavenging and catalysis. Crosslinked poly(1‐butyl‐3‐vinylimidazolium bromide) microspheres with the diameter of about 200 nm were synthesized via miniemulsion polymerization, in which 1,4‐di(vinylimidazolium) butane bisbromide was added as the crosslinker. Anion exchange of PIL microspheres with Pt precursor and followed by the reduction of Pt ions produced PIL microsphere supported Pt nanoparticle hybrids. The synthesized Pt nanoparticles with a diameter of about 2 nm are uniformly dispersed and strongly bound to the surface of PIL microspheres. The catalytic performances of PIL/Pt nanoparticle hybrids were evaluated for both the electrocatalytic oxidation of methanol and oxidation of benzyl alcohol. The PIL/Pt nanoparticle hybrids show better electrocatalytic activity towards the electrooxidation of methanol than pure Pt nanoparticles. Furthermore, they are effective and easily reusable catalysts for the selective oxidation of benzyl alcohol in aqueous reaction media, demonstrating that the synthesized PIL microspheres are suitable scaffolds for heterogeneous catalysts Pt. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Fabrication of poly(vinyl alcohol)‐graphene quantum dots coated with poly(3,4‐ethylenedioxythiophene) for supercapacitor

Conducting nanofiber composed of poly(vinyl alcohol) (PVA), graphene quantum dots (GQDs) and poly(3,4‐ethylenedioxythiophene) (PEDOT) was prepared for symmetrical supercapacitor through electrospinning and electropolymerization techniques. The formation of PVA nanofibers with the addition of GQDs was excellently prepared with the average diameter of 55.66 ± 27 nm. Field emission scanning electron microscopy images revealed that cauliflower‐like structure of PEDOT was successfully coated on PVA‐GQD electrospun nanofibers. PVA‐GQD/PEDOT nanocomposite exhibited the highest specific capacitance of 291.86 F/g compared with PVA/PEDOT (220.73 F/g) and PEDOT (161.48 F/g). PVA‐GQD/PEDOT also demonstrated a high specific energy and specific power of 16.95 and 984.48 W/kg, respectively, at 2.0 A/g current density. PVA‐GQD/PEDOT exhibited the lowest resistance of charge transfer (R_ct) and equivalent series resistance compared with PEDOT and PVA/PEDOT, indicating that the fast ion diffusion between the electrode and electrolyte interface. PVA‐GQD/PEDOT nanocomposite also showed an excellent stability with retention of 98% after 1000 cycles. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 50–58     

Polarons radical polymerization

Polystyrene has been typically prepared with radical polymerization by benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN). In this report, polymerization of styrene was carried out by radical cations of polyaniline (PANI). Polarons of conducting polymers are consisting of radical cations. The polarons bear electrical conduction as a charge carrier. We employ the polarons as an initiator for radical polymerization. Polymerization of styrene and acrylonitrile by the polarons was conducted to explore new possibility of conducting polymers. Fourier‐transfer infrared absorption (FTIR) spectroscopy measurements for the resultant polymers obtained with polarons of polyaniline indicates that the polystyrene thus synthesized grows from polyaniline. The qualitative solubility, average molecular weight, and thermal stability are comparable to that of polystyrene obtained by the common method with BPO. Radical polymerization by polarons may provide a new avenue for radical polymerizations through application of conducting polymer. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 805–811     

Pure blue electroluminescent poly(aryl ether)s with dopant–host systems

A series of novel arylene ether polymers (P5F‐BCzVFs) containing both pentafluorene (5F) and distyrylarylene derivative (BCzVF) units in the side chains for efficient pure blue light emission were prepared by a facile, metal‐free condensation polymerization. The emission spectra indicated that color tuning could be achieved through efficient Förster energy transfer from the deep‐blue 5F host to the pure‐blue BCzVF dopant. Single‐layer polymer light‐emitting diodes (PLEDs) based on P5F‐BCzVFs (ITO/(PEDOT:PSS)/polymer/Ca/Al) exhibited voltage‐independent and stable pure blue emission with a Commission International de L'Eclairage (CIE) coordinate of (0.15, 0.15), a maximum brightness of 3576 cd/m², and a maximum luminous efficiencies of 2.15 cd/A, respectively. As most polymers with dopant‐host systems, the luminous efficiencies of all P5F‐BCzVFs surpassed that of the host‐only polymer (P5F), due to the energy transfer and charge trapping from the host to the dopant. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Surfactant‐free synthesis of amphiphilic diblock copolymer in aqueous phase by a self‐stability process

Amphiphilic polymeric particles with hydrophobic cores and hydrophilic shells were prepared via living radical emulsion polymerization of styrene using a water‐soluble poly(acrylamide)‐based macro‐RAFT agent in aqueous solution in the absence of any surfactants. Firstly, the homopolymerization of acrylamide (AM) was carried out in aqueous phase by reversible addition‐fragmentation chain transfer radical polymerization (RAFT) using a trithiocarbonate as a chain transfer agent. Then the PAM‐based macro‐RAFT agent has been used as a water‐soluble macromolecular chain transfer agent in the batch emulsion polymerization of Styrene (St) free of surfactants. The RAFT controlled growth of hydrophobic block led to the formation of well‐defined poly(acrylamide)‐copolystyrene amphiphilic copolymer, which was able to work as a polymeric stabilizer (self‐stability). Finally, very stable latex was prepared, having no visible phase separation for several months. FTIR and ¹H‐NMR measurements showed that the product was the block copolymer PAM‐co‐PS in the form of stable latex. Atomic force microscope (AFM), transmission electron microscope (TEM), and dynamic light scattering (DLS) studies indicated that the nanoparticles have a narrow particle size distribution and the average particle hydrodynamic radius was kept in the diameter of 58 nm. Core‐shell structure of the copolymer was also recorded by TEM. The mechanism of the self‐stability of polymer particles during the polymerization in the absence of surfactants was studied. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3098–3107, 2008     

Tailor‐made hybrid nanostructure of poly(ethyl acrylate)/clay by surface‐initiated atom transfer radical polymerization

Hybrid nanoarchitecture of tailor‐made Poly(ethyl acrylate)/clay was prepared by surface‐initiated atom transfer radical polymerization (SI‐ATRP), by tethering ATRP initiator on active hydroxyl group, present in surface as well as in the organic modifier of the clay used. Extensive exfoliation was facilitated by using these initiator modified clay platelets. Poly(ethyl acrylate) chains with controlled polymerization and narrow polydispersities were forced to be grown from within the clay gallery (intergallery) as well as from the outer surface (extragallery) of the clay platelets. The polymer chains attached onto clay surfaces might have the potential to provide the composites with enhanced compatibility in blends with common polymers. Attachment of the initiator on clay platelets was confirmed by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), elemental analysis, Wide‐angle X‐ray diffraction (WAXD), and microscopic analysis. Finally, end group analysis (by Matrix‐Assisted Laser Desorption Ionization Mass Spectrometry, and chain extension experiment) of the cleaved polymer and morphological study (by WAXD, Transmission Electron Microscopy), performed on the polymer grafted clays examined the effect of grafting on the efficiency of polymerization and the degree of dispersion of clay tactoids in polymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5014–5027, 2008     

A comparative analysis of SET‐LRP of MA in solvents mediating different degrees of disproportionation of Cu(I)Br

Cu(I)Br/Me₆‐TREN species are unstable and disproportionate into metallic Cu(0) and Cu(II)Br₂/Me₆‐TREN in DMSO, whereas in toluene are stable and do not undergo disproportionation, at least at 25 °C. To estimate the role of the disproportionating solvent in single electron‐transfer living radical polymerization (SET‐LRP) a comparative analysis of Cu(0)/Me₆‐TREN‐catalyzed polymerization of MA initiated with methyl 2‐bromopropionate at 25 °C was performed in DMSO and toluene. A combination of kinetic experiments and chain end analysis by 500‐MHz ¹H NMR spectroscopy was used to demonstrate that disproportionation represents the crucial requirement for a successful SET‐LRP of MA at 25 °C. In DMSO a perfect SET‐LRP occurs and yields close to 100% conversion in 45 min. A first order polymerization in growing species up to 100% conversion and a PMA with perfectly functional chain ends are obtained. However, in toluene within 17 h only about 60% conversion is obtained, the polymerization does not show first order in growing species and therefore is not a living polymerization. Moreover, at 60% conversion the resulting PMA has only 80% active chain ends. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6880–6895, 2008     

Novel reversible thermoresponsive nanogel based on poly(ionic liquid)s prepared via RAFT crosslinking copolymerization

In this study, a facile strategy for the preparation of thermo‐ and pH‐responsive nanogels through reversible addition–fragmentation transfer (RAFT) crosslinking copolymerization of ionic liquid‐based monomers is demonstrated. The use of chain transfer agents (CTAs) containing carboxyl group in the RAFT polymerizations is the key to producing highly thermoresponsive nanogels. Experimental results demonstrate that the critical gelation temperature of the as‐prepared nanogels can be tuned by adjusting the feed ratio of monomer and CTA. Variable temperature Fourier transform infrared measurements and control experiments indicate that hydrogen‐bonding interactions between the carboxyl groups of CTAs are responsible for the thermoresponsive behaviors of poly(ionic liquid) (PIL)‐based nanogels. Furthermore, PIL‐based nanogels are also found to be pH‐sensitive, and can be further decorated by poly(N‐isopropylacrylamide) (PNIPAAm) via surface grafting polymerization. PNIPAAm‐grafted nanogel aqueous solutions can be reversibly transformed into macrogels upon a change in temperature. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 169–178     

Electrochemical synthesis of poly(3,4‐ethylenedioxythiophene) nanotube arrays using ZnO templates

A new method toward vertically oriented poly(3,4‐ethylenedioxythiophene) (PEDOT) nanotube arrays on transparent conductive oxide substrates is presented. The approach is based on the use of ZnO nanowire arrays as templates for the electropolymerization of PEDOT. Robust arrays of vertically oriented PEDOT nanotubes with different lengths and wall thicknesses were obtained by modifying the ZnO nanowire length and charge density passed during the electropolymerization, respectively. Furthermore, PEDOT nanotubes with different morphologies (top‐closed and mushroom‐like) were successfully designed by varying the PEDOT electropolymerization kinetics or monomer diffusion or both. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Effect of rate retardation in RAFT grafting polymerization from silicon wafer surface

Polystyrene and poly(butyl acrylate) were grafted from silicon wafer surface by reversible addition‐fragmentation chain transfer (RAFT) polymerization. Three RAFT agents were immobilized onto silicon wafer through their leaving/initiating groups (R group). Grafting polymerization of butyl acrylate (BA) and styrene (St) was then carried out from the immobilized RAFT agents. The immobilization of the RAFT agents and the subsequent grafting polymerization of St and BA were evaluated by ellipsometry and X‐ray photoelectron spectroscopy. It was found that type of monomer, structure of RAFT agent, and local RAFT concentration on the surface have dramatic influences on the thickness of grafted polymer layer. The grafting polymerization with more severe rate retardation effect yielded thinner polymer films on the silicon wafer. Selection of a RAFT agent with little rate retardation was critical in the grafting polymerization to achieve thick films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 970–978, 2008