Conjugated Polymer Actuators and Devices: Progress and Opportunities

Conjugated polymers (CPs), as exemplified by polypyrrole, are intrinsically conducting polymers with potential for development as soft actuators or “artificial muscles” for numerous applications. Significant progress has been made in the understanding of these materials and the actuation mechanisms, aided by the development of physical and electrochemical models. Current research is focused on developing applications utilizing the advantages that CP actuators have (e.g., low driving potential and easy to miniaturize) over other actuating materials and on developing ways of overcoming their inherent limitations. CP actuators are available as films, filaments/yarns, and textiles, operating in liquids as well as in air, ready for use by engineers. Here, the milestones made in understanding these unique materials and their development as actuators are highlighted. The primary focus is on the recent progress, developments, applications, and future opportunities for improvement and exploitation of these materials, which possess a wealth of multifunctional properties.     

Electrochemically stimulated 2‐ethylhexyl phosphate (EHP) release through redox switching of conducting polypyrrole film and polypyrrole/poly (N‐methylpyrrole) or self‐doped polyaniline bilayers

2‐Ethylhexyl phosphate (EHP) released from poly(pyrrole 2‐ethylhexyl phosphate) (PP‐EHP) was investigated at open circuit and compared with electrochemically stimulated release during potential cycling. It was found that the fast EHP release from the PP‐EHP single layer is substantially retarded and that amounts of spontaneously and electrochemically released EHP can be reduced by constructing bilayers, consisting of a PP‐EHP inner layer and a poly(N‐methylpyrrole)‐poly(styrene sulfonate) (PNMP‐PSS) or self‐doped poly(aniline) sulfonate (SPANI) as the outer films. The presence of outer film over the PP‐EHP allowed surface‐property modification, as well as the control of the rate of EHP release, while electrochemically stimulated EHP release from inner films was not substantially hampered by the outer layer. The quantity of the EHP released was investigated using UV‐vis spectrophotometery and an electrochemical quartz‐crystal microbalance (EQCM) during reduction of PP‐EHP from single layer and bilayers through electrochemical stimulation. EHP was reincorporated to the inner film by applying an anodic potential and then the release of EHP was performed again. The results showed that the outer film could act as a barrier to ion‐and solvent‐transport between the inner film and electrolyte, yielding a more balanced counter‐directional movement of anions. © 2002 Society of Chemical Industry     

Electrocatalytic oxidation of hydrazine at overoxidized polypyrrole film modified glassy carbon electrode

Electrocatalytic oxidation of hydrazine (HZ) was studied on an overoxidized polypyrrole (OPPy) modified glassy carbon electrode using cyclic voltammetry and chronoamperometry techniques. The OPPy-modified glassy carbon electrode has very high catalytic ability for electrooxidation of HZ, which appeared as a reduced overpotential in a wide operational pH range of 5-10. The overall numbers of electrons involved in the catalytic oxidation of HZ, the number of electrons involved in the rate-determining and diffusion coefficient of HZ were estimated using cyclic voltammetry and chronoamperometry. It has been shown that using the OPPy-modified electrode, HZ can be determined by cyclic voltammetry and amperometry with limit of detection 36 and 3.7 μM, respectively. The results of the analysis suggest that the proposed method promises accurate results and could be employed for the routine determination of HZ.     

Tuning the optical properties of poly(o-phenylenediamine-co-pyrrole) via template mediated copolymerization

Tailoring of conjugated monomers via copolymerization is a facile method to obtain tunable spectral, morphological and optical properties. To investigate the effect of copolymerization of pyrrole with o-phenylenediamine on the optoelectronic properties of the synthesized copolymers, the present work reports the synthesis of copolymers of o-phenylenediamine with pyrrole with varying mol ratios via chemical polymerization in methylene blue (MB) medium. Copolymerization was confirmed by Fourier transform infrared spectroscopy and ultraviolet-visible studies. Ultraviolet-visible spectroscopy revealed variation in the optical properties with the change in the monomer ratio. Fluorescence studies showed that the copolymer containing 80% poly(o-phenylenediamine) revealed highest quantum yield among all the copolymers. The emission color could therefore be tuned by careful selection of narrow band co-monomers, which could help in designing tunable fluorescence emitting materials for potential application in OLED devices.     

Silver nanoparticles decorated polypyrrole/graphene nanocomposite: A potential candidate for next‐generation supercapacitor electrode material

In the present study, we report a simple method to synthesize silver (Ag)‐polypyrrole (PPy)/graphene (Gr) nanocomposite as efficient electrode materials for supercapacitor application. The probable interaction between Ag nanoparticles with both PPy and Gr were characterized by FTIR, UV–visible, and Raman spectroscopies. The morphological analysis confirmed that the Gr sheets are uniformly coated by PPy and in the coated Gr sheets there is the presence of Ag nanoparticles. The Ag‐PPy/Gr nanocomposite achieved the highest specific capacitance of 472 F/g at a 0.5 A/g current density. Better energy and power density also obtained for the nanocomposite. The presence of both Ag nanoparticles and Gr is the main reason for the enhancement of the electrochemical properties of the nanocomposite. Based on the superior electrochemical properties, the nanocomposite can be used for next‐generation supercapacitor electrode material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44724.     

Nafion/polypyrrole and Nafion/DMSO Organic Coatings for Magnesium Protection

Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.     

Complexation of poly(pyrrole-EDTA like) film modified electrodes: Application to metal cations electroanalysis

Complexing polymer-coated electrodes have been synthesized by oxidative electropolymerization of N,N′-ethylenebis[N-[(3-(pyrrole-1-yl)propyl) carbamoyl) methyl]-glycine] (L). There were used for the electrochemical detection of Cu(II), Pb(II) and Cd(II) ions by means of the chemical preconcentration-anodic stripping technique. For thick polymeric binding materials and long accumulation times, competitive experiments showed that the polyL film modified electrodes are selective towards Cu(II) ions and particularly insensitive to the presence of Cd(II). In contrast, imprinted polymer-coated electrodes prepared by electropolymerization of the Cd(II) complex of L allowed an efficient complexation and sensing of Cd(II) cations. The selectivity of the molecular electrode materials can thus be subtly modulated upon playing on the accumulation time and on the pre-structuration of the complexing polymers.     

含钕硅钼钨杂多酸盐电催化性能的研究

报道了含钕硅钼杂多酸盐在水溶液中及其修饰到聚吡咯膜里的电化学性质,并对Ｈ２Ｏ２还原反应的催化作用进行了研究,提出了可能的机理。     

可拉伸聚吡咯/棉针织物的制备及其储电性能

为赋予棉针织物导电和储电的新功能并将其用于可穿戴器件中,将吡咯单体原位聚合到棉针织物上。借助扫描电子显微镜和红外光谱仪对棉针织物和聚吡咯的微观形貌以及化学结构进行表征,并测试了聚吡咯/棉针织物在不同拉伸应变时的表面电阻及电化学性能。结果表明:聚吡咯充分附着在针织棉纤维上;当拉伸应变从0%增至40%时,织物电阻值从429.2 Ω降至231.4 Ω;织物在5 mV/s条件下的储电面积容量为680.6 mF/cm ²,在2 mA/cm² 条件下为1 014.2 mF/cm²;由聚吡咯/棉针织物组装成的对称型超级电容器在1、5 mA/cm²时的面积容量分别为229.8、161.5 mF/cm²,经过10 000次恒流充放电循环后容量保留率为76.3%。     

A water‐soluble self‐doped conducting polypyrrole‐based copolymer

A water‐soluble self‐doped conducting polypyrrole‐based copolymer was synthesized via the grafting of pyrrole onto the p‐aminodiphenylamine moieties of a water‐soluble copolymer. The conductive copolymer exhibited a conductivity as large as 3.4 S/cm. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 86–89, 2001