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     

Synthesis and characterization of single‐wall‐carbon‐nanotube‐doped emeraldine salt and base polyaniline nanocomposites

Nanocomposites of polyaniline (PANI) and single‐wall carbon nanotubes (SWNTs) were prepared and characterized via resonance Raman and electronic absorption spectroscopy (ultraviolet–visible/near‐infrared). The chemical synthesis of PANI was performed in the presence of SWNTs in concentrations ranging from 10 to 50 wt % (SWNT/PANI). The obtained materials were hydrophilic, homogeneous composite compounds. The chemical interaction between PANI (in the conducting emeraldine salt form and in the insulating emeraldine base form) and metallic and semiconducting nanotubes was investigated. The emeraldine salt form of the polymer was significantly stabilized in the composite in comparison with plain PANI. A selective electronic interaction process between PANI and metallic SWNTs was found. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 815–822, 2005     

Enhanced dielectric properties of polymer composite films induced by encapsulated MWCNTs with a one core‐two shell structure

Multiwalled carbon nanotubes (MWCNTs) can endow high dielectric constant to polymer‐based composites. However, the accompanying poor dispersion of MWCNTs and high dielectric loss for composites severely limit their application in dielectric field. Herein, a modified acid‐treated MWCNTs encapsulated by the polyaniline/poly(sodium 4‐styrenesulfonate) layers (aMWCNTs@PANI‐PSS) with a one core‐two shell structure was fabricated by in situ polymerization followed by electrostatic self‐assembly technique. Furthermore, the composite films based on aMWCNTs@PANI‐PSS/poly(vinylidenefluoride‐hexaflouropropylene) (PVDF‐HFP) were fabricated by a solution‐casting method. An ultrathin insulating PSS shell is wrapped onto aMWCNTs@PANI, resulting in the improvement of dispersibility for aMWCNTs@PANI and the decrease of dielectric loss for composite films. When the content of aMWCNTs@PANI‐PSS is 5.0 wt %, the dielectric constant of aMWCNTs@PANI‐PSS/PVDF‐HFP reaches 430 (100 Hz), which is about 55 times of pure PVDF‐HFP and 1.7 times of aMWCNTs@PANI/PVDF‐HFP (247). Besides, the responding dielectric loss of aMWCNTs@PANI‐PSS/PVDF‐HFP composite film is only 0.67, much lower than that of aMWCNTs@PANI/PVDF‐HFP (25) and aMWCNTs/PVDF‐HFP (3185). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 948–956     

Thermoresponsive graphene oxide‐PNIPAM nanocomposites with controllable grafting polymer chains via moderate in situ SET–LRP

In this study, we report a mild and efficient strategy for growing thermosensitive polymers directly from the surface of exfoliated graphene oxide (GO). Exfoliated GO sheets were sequentially subject to the epoxide ring‐opening reaction with tris(hydroxymethyl) aminomethane (TRIS) to increase the amount of reactive sites, the esterification with 2‐bromo‐2‐methylpropionyl bromide to introduce the Br‐containing initiating groups, and the surface‐initiated single electron transfer–living radical polymerization of N‐isopropylacrylamide (NIPAM) to tune the molecular weights of grafted polymers. All these reactions were performed at ambient temperature without losing any other oxygen‐containing functionality on GO. The resulting TRIS‐GO‐PNIPAM nanocomposites still maintain the separated single layers in dispersion, and the dispersibilities in organic solvents are significantly improved. Meanwhile, the aqueous dispersion of TRIS‐GO‐PNIPAM shows reversible temperature switching self‐assembly and disassembly behavior at about 40°C. Such smart graphene‐based hybrid materials are promising for applications in nanoelectronics, sensors, and microfluidic switches. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

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     

Enzymatic‐catalyzed polymerization of water‐soluble electrically conductive polymer PEDOT:PSS

Water‐soluble electrically conductive polymer poly(3,4‐ethylenedioxythiophene) (PEDOT) was synthesized by the enzymatic‐catalyzed method using 3,4‐ethylenedioxythiophene (EDOT) as monomer, poly(styrenesulfonate) (PSS) as water‐soluble polyelectrolyte, horseradish peroxidase enzyme as catalyst, and hydrogen peroxide (H₂O₂) as oxidant. Fourier transform infrared spectra and UV–vis absorption spectra confirm the successful enzymatic‐catalyzed polymerization of PEDOT. Dynamic light scattering data confirm the formation of a stable PEDOT:PSS aqueous dispersion. The thermo gravimetric data show that the obtained PEDOT is stable over a fairly high range of temperatures. The atomic force microscopy height images show that the PEDOT:PSS aqueous dispersion can form excellent homogeneous and smooth films on various substrates by conventional solution processing techniques, which renders this PEDOT:PSS aqueous dispersion a very promising candidate for various application in electronic devices. This enzymatic polymerization is a new approach for the synthesis of optical and electrical active PEDOT polymer, which benefits simple setting, high yields, and environmental friendly route. Copyright © 2014 John Wiley & Sons, Ltd.     

Preparation of polyaniline grafted multiwalled carbon nanotubes and conductive application in polyetherimide

A methodology for improving antistatic property of polyetherimide (PEI) composite using polyaniline (PANI) grafted multi‐walled carbon nanotubes (MWNTs) as conductive medium was proposed. First, the MWNTs grafted with PANI (PANI‐g‐MWNTs) were prepared by in‐situ polymerization in an emulsion system. Subsequently, PANI‐g‐MWNTs were blended with PEI using N‐methyl‐2‐pyrrolidone as solvent. After removing the solvent, the PEI/PANI‐g‐MWNT composite was prepared. As assisted conductive medium, the grafted PANI molecular chains on MWNT surface were dispersed in the PEI matrix to decrease the percolation value of the antistatic composites. The structure and morphology of PANI‐g‐MWNTs were characterized by Fourier transform infrared spectroscopy, transmission electron microscope, thermogravimetric analysis, and X‐ray powder diffraction, respectively. The dispersion of PANI‐g‐MWNTs in PEI matrix was studied by scanning electron microscope. The electrical performance was characterized by highly resistant meter. The volume resistivity of the conductivity percolation threshold was 1.781 × 10^?8 S/cm when the loading of PANI‐g‐MWNTs was 1.0 wt%. The conductivity of PANI‐g‐MWNTs/PEI composites was found to be higher than that of pristine MWNTs/PEI composite. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of graphene reinforcement in conductive polymer: Synthesis and characterization

Lightweight conductive polymers are considered for lightning strike mitigation in composites by synthesizing intrinsically conductive polymers (ICPs) and by the inclusion of conductive fillers in insulating matrices. Conductive films based on polyaniline (PANI) and graphene have been developed to improve through‐thickness conductivity of polymer composites. The result shows that the conductivity of PANI enhanced by blending polyvinylpyrrolidone (PVP) and PANI in 3:1 ratio. Conductive composite thin films are prepared by dispersing graphene in PANI. The conductivity of composite films was found to increase by 40× at 20 wt% of graphene inclusion compared with PVP and PANI blend. Fourier‐transform‐infrared (FTIR) spectra confirmed in situ polymerization of the polymer blend. The inclusion of graphene also exhibits an increase in Tg by 21°C. Graphene additions also showed an increase in thermal stability by approximately 148°C in the composite films. The mechanical result obtained from DMA shows that inclusion of graphene increases the tensile strength by 48% at 20 wt% of graphene reinforcement. A thin, highly conductive surface that is compatible with a composite resin system can enhance the surface conductivity of composites, improving its lightning strike mitigation capabilities.     

On the structure and electrical conductivity of polyaniline/polystyrene blends prepared by an aqueous‐dispersion blending method

This article describes electrically conductive polymer blends containing polyaniline‐dodecyl benzene sulfonic acid (PANI‐DBSA) dispersed in a polystyrene (PS) matrix or in crosslinked polystyrene (XPS). Melt blending of previously mixed, coagulated, and dried aqueous dispersions of PANI‐DBSA and PS latices lead to high conductivities at extremely low PANI‐DBSA concentrations (∼0.5 wt % PANI‐DBSA). In these blends, the very small size of the PANI‐DBSA particles and the surface properties (with surfactants used) of both the PANI and polymer particles play a major role in the PANI‐DBSA particle structuring process. The PANI‐DBSA behavior is characteristic of a unique colloidal polymeric filler with an extremely high surface area and a strong interaction with the matrix, evidenced by a significantly higher glass‐transition temperature of the matrix. The effect of the shear level on the conductivity and morphology of the PS/PANI‐DBSA blends was studied by the production of capillary rheometer filaments at various shear rates. An outstanding result was found for XPS/PANI‐DBSA blends prepared by the blending of aqueous XPS and PANI‐DBSA dispersions. Some of these blends were insulating at low shear levels; however, above a certain shear level, smooth surface filaments were generated, with dramatically increased and stable conductivities. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 611–621, 2001     

Facile green strategy for micro/nano structured conducting polyaniline‐clay nanocomposite via template polymerization using amphiphilic dopant, 3‐pentadecyl phenol 4‐sulphonic acid

Novel self‐assembled nano/microstructured conducting PANICN was prepared by in situ intercalative emulsion polymerization of aniline in aqueous dispersion of clay using bifunctional amphiphilic dopant, 3‐pentadecyl phenol‐4‐sulphonic acid (PDPSA) derivable from renewable resource. X‐ray diffraction and scanning electron microscopy (SEM) studies revealed the formation of monolayer of protonated PANI intercalated nanoclays with template polymerized self‐assembled micro/nanostructured protonated PANI. Nano/micro structured PANIs were formed by the supra molecular self‐assembling of the inter‐chain hydrogen bonding, inter‐plane phenyl stacking and electrostatic layer by layer self‐assembling (ELBS) between polarized alkyl chains present dopant anions and were manifested using fourier transform infra red spectroscopy and differential scanning calorimetry. On the basis of the results, structure‐directing effect of ‘anilinium salt micelle’ was schematically illustrated in this article. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2664–2673, 2007     

Thermosensitive graphene nanocomposites formed using pyrene‐terminal polymers made by RAFT polymerization

Thermosensitive graphene‐polymer composites have been prepared by attaching poly(N‐isopropylacrylamide) (PNIPAAm) onto the basal plane of graphene sheets via π‐π stacking. Pyrene‐terminated PNIPAAm was synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization via a pyrene‐functional RAFT agent. Aqueous solutions of the graphene‐polymer composites were stable and thermosensitive. The lower critical solution temperature (LCST) of pyrene‐terminated PNIPAAm was measured to be 33 °C. When the pyrene‐functional polymer was attached to graphene the resultant composites were also thermosensitive in aqueous solutions exhibiting a reversible suspension behavior at 24 °C. Atomic force microscopy (AFM) analysis revealed that the thickness of a graphene‐PNIPAAm (M_n: 10,000 and PDI: 1.1) sheet was ～5.0 nm. The surface coverage of polymer chains on the graphene basal plane was calculated to be 7.2 × 10^?11 mol cm^?2. The graphene‐PNIPAAm composite material was successfully characterized using X‐ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR‐IR) spectroscopy, and thermogravimetric analysis (TGA). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 425–433, 2010     

Synthesis and characterization of polyaniline–polyamidoamine dendrimer blends

A novel conductive blend of polyaniline (PANI) with polyamidoamine dendrimer (PAMAM (G 2.0)) was prepared by different blending procedure. The PANI‐PAMAM blended polymers were characterized by UV–vis, FTIR, and electron paramagnetic resonance (EPR) spectra. The effect of varying the blending procedure on structure and EPR properties of PANI‐PAMAM blended polymers was investigated. Varying the blending procedure and temperature has a direct effect on the structure and EPR parameters (ΔH_PP, g factor, N_S, T₂, and A/B ratio). EPR spectroscopic studies suggested the presence of chemical interaction between PANI and PAMAM. Electron localization effects in PANI‐PAMAM blended polymers can therefore be studied using the technique of EPR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1–8, 2006     

Preparation and characterization of PVC/PANI conductive composite with extremely low percolation threshold

Aniline was polymerized in the presence of poly(vinyl chloride) (PVC) powders in hydrochloric acid to in situ prepare poly(vinyl chloride)/polyaniline (PVC/PANI) composite particles. UV‐vis spectra and FT‐IR spectra indicate PANI in PVC/PANI composite particles possessed a higher oxidation state with decreased aniline content in reactants. Both conductivity and impact strength of the dodecylbenzenesulfonic acid (DBSA) doped PANI composites (PVC/PANI‐DBSA), which were compression molded from the in situ prepared PVC/PANI particles, increase with the pressing temperature and decrease with the increase of DBSA doped PANI (PANI‐DBSA) loading. An excellent electric conductivity of 5.06 × 10^?2 S/cm and impact strength of 0.518 KJ/m² could be achieved for the in situ synthesized and subsequently compression molded composite. Copyright © 2004 John Wiley & Sons, Ltd.     

一步共沉积法制备ZSM-5/PANI/PSS电活性膜及其电控选择性分离重金属Pb2+的动力学特性

本文采用双脉冲一步共沉积法制备了ZSM-5/聚苯胺/聚苯乙烯磺酸钠(ZSM-5/PANI/PSS)电活性膜,通过FT-IR、XRD和SEM对ZSM-5/PANI/PSS电活性膜进行了表征. 由水热法合成纳米级ZSM-5颗粒,经超声处理将ZSM-5分散,有利于合成均匀的ZSM-5/PANI/PSS电活性膜. 实验结果表明该电活性膜对Pb²⁺具有优良的选择分离性能,在10 mg﹒L^-1的Pb²⁺溶液中电控离子交换法对Pb²⁺的去除率是传统离子交换法的2.3倍,且前者的平衡吸附量是后者的2.5倍. 吸附过程满足Langmuir等温吸附方程,ZSM-5/PANI/PSS电活性膜对Pb²⁺的交换量高达235 mg·g^-1. 吸附过程为准一级动力学吸附,电控离子交换过程的准一级吸附速率常数(0.0227 g·mg^-1·min^-1)明显高于传统离子交换(0.0117 g·mg^-1·min^-1). 该电活性膜在电控离子交换处理废水领域具有很好的应用前景.     

Syntheses of conductive adhesives based on epoxy resin and polyanilines by using N‐tert‐butyl‐5‐methylisoxazolium perchlorate as a thermally latent curing reagent

Conductive composites consisted of epoxy resin and polyanilines (PANIs) doped with dodecylbenzenesulfonic acid ( 1 ), dodecylsulfonic acid (2), di(2‐ethylhexyl)sulfosuccinic acid (3), and HCl were synthesized by use of N‐tert‐butyl‐5‐methylisoxazolium perchlorate (5) under various reaction conditions. It was found that the composites with PANI doped with acid 2 (PANI‐2) prepared by curing with 10 mol % of reagent 5 at 80 °C for 12 h showed high electroconductivity along with the low conducting percolation threshold (3 wt % of PANI‐2). Furthermore, the composite with even ?10 wt % of PANI‐2 exhibited ?10^?1 S/cm of electroconductivity. The UV–vis and IR measurements indicated that the conductive emeraldine salt form of PANI‐2 in the composite was maintained after the curing reaction. The thermal stability was studied by TGA and DSC measurements, and then, the T_d10 and T_g of the composite with 5 and 10 wt % of PANI‐2 were found to be similar to those with the cured epoxy resin itself. In addition, the similar investigation with an oxetane resin instead of the epoxy resin was also carried out. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 718–726, 2006     

Simultaneous synthesis of silver nanoparticles and poly(2,5‐dimethoxyaniline) in poly(styrene sulfonic acid)

Silver nanoparticles were formed in situ along with poly(2,5‐dimethoxyaniline) (PDMA) in an interconnected network matrix (reactor), comprising the electronic conductive polymer, PDMA, and a polyelectrolyte, poly(styrene sulfonic acid) (PSS), through the simultaneous reduction of Ag⁺ ions and polymerization of 2,5‐dimethoxyaniline. In situ ultraviolet‐visible spectroscopy showed that peaks corresponding to the plasmon resonance of silver nanoparticles at 411 nm and the polaronic transition of PDMA at 438 nm provided evidences for the simultaneous formation of silver nanoparticles and PDMA. Transmission electron microscopy and size distribution analysis revealed the presence of spherical silver nanoparticles with an average diameter of 12 nm in the composite. X‐ray photoelectron spectroscopy showed that the amine units in PDMA changed to imine units upon the formation of silver nanoparticles. A comprehensive mechanism for the formation of the PDMA‐PSS‐Ag nanocomposite is proposed. A 10‐fold increase in the conductivity was noticed for the PDMA–PSS–Ag nanocomposite (1 S/cm) in comparison with the PDMA–PSS composite (0.1 S/cm). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3843–3852, 2006     

自支撑石墨烯/聚苯胺纳米纤维薄膜的制备及其电化学电容行为

用真空抽滤氧化石墨（GO）与聚苯胺（PANI）纳米纤维的混合分散溶液,流动组装得到自支撑GO/PANI复合薄膜,再利用气态水合肼还原其中的GO,最后重新氧化和掺杂还原态PANI,制备了自支撑石墨烯（GN）/PANI薄膜.扫描电子显微镜（SEM）结果显示,GN/PANI薄膜为层状结构,且PANI纳米纤维均匀插层于GN片间.PANI纳米纤维在复合薄膜中的存在有效增大了GN之间的层间距,有利于电解液离也GN充分接触.GN的高电导性则有利于PANI氧化还原过程中的电荷传输.电化学测试表明,GN/PANI薄膜在1 mol·L^-1HCl电解液中具有良好的电化学电容性能,在0.1 A·g^-1的电流密度下的比容量为495 F·g^-1,在3A·g^-1时为313 F·g^-1.经过2000次连续充放电,其具有90%的电容保持率,表明该复合材料具有良好的电化学稳定性.     

Graphene oxide‐induced polymerization and crystallization to produce highly conductive polyaniline/graphene oxide composite

Graphene oxide (GO)–polyaniline (PANI) composite is synthesized by in situ polymerization of aniline in the presence of GO as oxidant, resulting in highly crystalline and conductive composite. Fourier transform infrared spectrum confirms aniline polymerization in the presence of GO without using conventional oxidants. Scanning electron microscopic images show the formation of PANI nanofibers attached to GO sheets. X‐ray diffraction (XRD) patterns indicate the presence of highly crystalline PANI. The sharp peaks in XRD pattern suggest GO sheets not only play an important role in the polymerization of aniline but also in inducing highly crystalline phase of PANI in the final composite. Electrical conductivity of doped GO–PANI composite is 582.73 S m^?1, compared with 20.3 S m^?1 for GO–PANI obtained by ammonium persulfate assisted polymerization. The higher conductivity appears to be the result of higher crystallinity and/or chemical grafting of PANI to GO, which creates common conjugated paths between GO and PANI. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1545–1554     

Fabrication of Polyaniline/Graphene/Polyester Textile Electrode Materials for Flexible Supercapacitors with High Capacitance and Cycling Stability

Vertical polyaniline (PANI) nanowire arrays on graphene‐sheet‐coated polyester cloth (RGO/PETC) were fabricated by the in situ chemical polymerization of aniline. The 3D conductive network that was formed by the graphene sheets greatly enhanced the conductivity of PANI/RGO/PETC and improved its mechanical stability. PANI nanowire arrays increased the active surface area of PANI, whilst the hierarchically porous structure of the PANI/RGO/PETC electrode facilitated the diffusion of the electrolyte ions. Electrochemical measurements showed that the composite electrode exhibited a maximum specific capacitance of 1293 F g^?1 at a current density of 1 A g^?1. Capacitance retention was greater than 95 %, even after 3000 cycles, which indicated that the electrode material has excellent cycling stability. Moreover, the electrode structure endowed the PANI/RGO/PETC electrode with a stable electrochemical performance under mechanical bending and stretching.     

Facile preparation of highly conductive,flexible, and strong carbon nanotube/polyaniline composite films

In general, the high electrical conductivity (EC) comes into conflict with the good flexibility and high strength of carbon nanotube (CNT)/polyaniline (PANI) composites. In other words, a high CNT content will bring about a high EC but lead to a low flexibility and strength due to the CNT‐constrained matrix deformation and CNT aggregation. In this work, a highly conductive, flexible and strong CNT/PANI composite film prepared via a facile solvent‐evaporation method is readily obtained by a cold stretching. The cold stretching is conducted at room temperature for the CNT/PANI film. It is observed that the cold stretching process leads to an unexpectedly enhanced EC. The as‐obtained EC of 231 S/cm is much higher than that (2 – 50 S/cm) of the previously reported CNT/PANI composite films. Meanwhile, the strength is obviously improved over that of the pure PANI film and the good flexibility is maintained to a high degree by the introduction of a proper CNT content. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1575–1585