Synthesis and Characterization of Conducting Polyanilines via Catalytic Oxidative Polymerization

Polyanilines have been prepared by catalytic oxidative polymerization of aniline in an acidic solution using H₂O₂ as an oxidant and ferrous sulfate as a catalyst in presence of light by photo-Fenton process. The structures of polyanilines were elucidated by UV-vis, Fourier transform infrared, and nuclear magnetic resonance spectroscopy, which confirmed the presence of benzenoid and quinoid rings in the polyanilines. Molecular weight and specific surface area were determined by gel permeation chromatography and BET analysis. The differential scanning calorimetry results and two-probe conductometry studies showed that samples had good thermal stability and electroactivity.     

Novel dye-substituted polyanilines: conducting and antimicrobial properties

Conducting and antimicrobial properties of chemically synthesized dye-substituted polyanilines were found to be affected by varying the dye moieties. The dye-polyanilines were characterized by various analytical techniques including UV–visible spectroscopy, IR spectroscopy, fluorescence spectroscopy, AC impedance and thermo-gravimetric analysis and X-ray diffraction. The temperature dependence of DC conductivity was studied by two-probe method to learn about the conduction behavior in the synthesized compounds. The conductivity of the dye-substituted polyanilines was found to be in the range of 10^?3–10^?2 Scm^?1. For the study of antimicrobial behavior of the synthesized polyanilines, different microorganisms, including the bacteria Escherichia coli (MTCC 442), Pseudomonas aeurginosa (MTCC 441), Staphylococus aureus (MTCC 96), and S. pyogenus (MTCC 443) and fungal strains Candida albicans (MTCC 227), Aspergillus niger (MTCC 282) and A. clavatus (MTCC 1323), were chosen based on their clinical and pharmacological importance.     

Synthesis of needle‐like polyanilines

Needle‐like polyanilines were prepared in aqueous media by chemical oxidation. p‐Toluenesulfonic acid (pTSA) was used to protonate aniline (ANi) and readily made the anilinium complex. By slowly adding ammonium peroxydisulfate (APS) at 15°C, polyanilines were prepared in the micelles and grew to be needle‐like aggregates potentially useful as conductive fillers for electromagnetic interference shielding and radar‐absorbing materials. The needle‐like aggregates of protonated polyaniline prepared at 15°C and 0.5 M aniline concentration with 3 h of APS addition time showed conductivity up to 3 S/cm and a maximum aspect ratio of 26 L/D. They were observed by scanning electron microscopy to peel off partially into fibrils after washing. The needle‐like polyaniline‐pTSA complexes prepared with 0.5 M aniline concentration showed good thermal stability up to 200°C. The high conductivity of the needle‐like aggregates was ascribed to their well‐developed crystalline structures, compared with those of spherical particles. J. VINYL ADDIT. TECHNOL., 13:76–86, 2007. © 2007 Society of Plastics Engineers.     

Cyclic polyaniline nanostructures from aqueous/organic interfacial polymerization induced by polyacrylic acid

Cyclic nanostructural polyanilines have been synthesized by means of a simple modified aqueous/organic interfacial polymerization with the aid of polyacrylic acid, and yet only nanofiber nanostructural polyanilines were obtained by conventional interfacial polymerization in the presence of polyacrylic acid. These nanostructures were characterized using TEM, X-ray diffraction and UV-vis. The cyclic polyaniline nanostructures were formed by severe secondary overgrowth through the electrostatic interaction between aniline/oligoaniline and polyacrylic acid chains. The average diameter of the obtained cyclic-structure was ca. 400 nm and its conductivity was 1.06 S/cm.     

Broadband luminescence and emission enhancement

Three novel quinoline– and fluorene–coumarin hybrids were prepared and characterised by Fourier Transform–infrared spectroscopy, proton and carbon nuclear magnetic resonance spectroscopy, mass spectrometry, elemental analysis and ultraviolet–visible spectrophotometry. Their photoluminescence properties were investigated. All of these hybrid molecules exhibited a broadband emission from ca. 450 to 800 nm when excited by a 325 nm helium–cadmium laser at room temperature. Importantly, the fluorene–coumarin hybrid shows a very bright red emission at ca. 650 nm and displays up to a 10‐fold increase in fluorescence emission intensity, as compared with the other samples. The experimental results confirm that remarkable enhancements in the fluorescence emission intensity can be obtained by introducing a fluorene group into the azo‐bridged coumarin‐based π‐conjugated framework. The geometry structures and frontier orbitals are calculated by the ab initio Hartree–Fock method.     

Polymeric ionic liquid—assisted polymerization for soluble polyaniline nanofibers

To enhance the solubility of polyanilines(PANI),polymeric ionic liquid(PIL)was introduced into the polymerization synthesis of PANI with various proportions.The structure and properties of the modified PANIs were characterized by 1H NMR,Fourier transform infrared spectroscopy,thermogravimetric analysis,ultraviolet-visible spectrum,etc.It was found that the obtained PANIs doped with PILs were soluble in various organic solvents such as N,N-dimethyl formamide and acetonitrile.Compared with the pure PANI,the PANIs doped by PILs showed remarkable solubility and their chemical structure and conductivity kept integrated.     

Molecular simulation of plasma polymerized polyaniline-iodine compounds

This work presents a molecular simulation study of plasma-polymerized polyaniline-iodine compounds. The simulation is focused on the ortho, meta and para substitutions of aniline benzene rings where the polymers can grow into the maximum and partially reduced and oxidized states of polyanilines. This simulation offers the possibility of visualizing the spatial conformation of polyanilines while interacting with iodine atoms with and without chemical bonds between them. Such cases are often found in plasma polymerization and doping processes.     

Synthesis,spectral analysis,and catalytic activity of poly(aniline‐co‐congored)–metal oxide nanocomposites

Electrically conducting, water‐soluble fluorescent copolymer nanocomposites were synthesized by a solution polymerization method under different experimental conditions in the presence of CuO and V₂O₅ nanoparticles. The prepared copolymer nanocomposites were characterized with analytical tools, including Fourier transform infrared spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and fluorescence emission spectroscopy. The order of copolymerization was determined on the basis of the UV–vis absorption spectra and fluorescence emission spectra. The copolymer–CuO nanocomposite system exhibited the highest electrical conductivity. The scanning electron microscopy image showed the presence of more CuO nanoparticles on the surface of the copolymer. Furthermore, the catalytic activity of the copolymer nanocomposites was tested for the reduction of p‐nitrophenol. All three types of polymer systems exhibited almost the same apparent rate constant values. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46469.     

Hard X-ray photon-in photon-out spectroscopy

Spectroscopic techniques to study the electron configuration and local coordination of a central atom by detecting inner-shell radiative decays following photoexcitation using hard X-rays are presented. The experimental setup requires an X-ray spectrometer based on perfect crystal Bragg optics. The possibilities arising from non-resonant and resonant X-ray emission spectroscopy are discussed when the instrumental energy broadenings of the primary (beamline) monochromator and the crystal spectrometer for X-ray emission detection are on the order of the core hole lifetimes of the intermediate and final electronic states. The small energy bandwidth in the emission detection yields line-sharpened absorption features. In transition metal compounds, electron–electron interactions as well as orbital splittings and fractional population can be revealed. Combination with EXAFS spectroscopy enables to extend the k-range beyond unwanted absorption edges in dilute samples that limit the EXAFS range in conventional absorption spectroscopy.     

Synthesis and characterization of biodegradable polymers composed of 3,4-dihydroxycinnamic acid and poly(ethylene glycol)

A novel series of biodegradable copolymers were synthesized by the thermal polycondensation of 3,4-dihydroxycinnamic acid (DHCA) and poly(ethylene glycol) (PEG). The copolymers were characterized by ¹H-NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. It was found that the incorporation of PEG reduced the glass-transition temperature (T_g) of the copolymers, and T_g decreased with increasing amount of PEG in the compositions. The fluorescence spectroscopy revealed that the homopolymer and copolymers of DHCA gave a higher fluorescence emission intensity than that of DHCA monomer, of which the strongest fluorescence emission peak occurred in the copolymers containing a small amount of PEG. X-ray diffraction spectra demonstrated that poly(3,4-dihydroxycinnamic acid) and copolymer were amorphous; this indicated the facile biodegradability of the copolymers. Furthermore, copolymer micelles formed by self-assembly were investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Metallopolymers based on a polyazomethine ligand containing rigid oxadiazole and flexible tetramethyldisiloxane units

Soluble, easily processable polymer–metal complexes with improved optical and dielectric properties for optoelectronic functional materials were obtained. For this, a new polyazomethine (PAZ2) was prepared by the reaction of a siloxane dialdehyde and bis(formyl‐p‐phenoxymethyl) tetramethyldisiloxane with 2,5‐bis(p‐aminophenyl)‐1,3,4‐oxadiazole, and it was used as a ligand for Cu(II), Co(II), and Zn(II) ions on the basis of the presence of the electron‐donor nitrogen atoms from the azomethine group and oxadiazole ring. The structure of the PAZ2 was determined by spectral [Fourier transform infrared (FTIR) and ¹H‐NMR spectroscopy] techniques. The metal complexation was proven by FTIR spectroscopy, and the silicon‐to‐metal ratios in the complexes were established by energy‐dispersive X‐ray fluorescence. The new materials were characterized by gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. The optical properties of PAZ2 and the derived metal complexes were studied by ultraviolet–visible and fluorescence spectroscopies. PAZ2 shows fluorescence emission, and it was significantly enhanced by metal complexation. The emission was enhanced by protonation; this behavior is useful, especially for sensors. The electrical properties were investigated by dielectric spectroscopy at various frequencies and temperatures, and this emphasized the existence of dipolar relaxations. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41631.     

Polyaniline‐grafted polyurethane coatings for corrosion protection of mild steel surfaces

We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10^?2 to 10^?3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45806.     

Synthesis and physicochemical properties of poly[2‐(2‐chloro‐1‐methylbut‐2‐en‐1‐yl)aniline] obtained with various dopants

Highly soluble polyaniline was synthesized from a newly designed aniline derivative, namely 2‐[2‐chloro‐1‐methylbut‐2‐en‐1‐yl]aniline. The corresponding polyanilines, PClPA‐HA, PClPA‐SA, PClPA‐NA and PClPA‐PA, were characterized by means of ¹H NMR, ¹³C NMR, high resolution mass spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy and SEM images. The elemental analysis and electrical conductivity of the polymers are also presented. It is shown that the molecular weight of the polymers obtained depends on the method of synthesis. Spectroscopic studies confirmed the emeraldine form of the polyaniline derivatives. In the work, the dependence of the current passing through resistive structures based on thin poly[2‐(2‐chloro‐1‐methylbut‐2‐en‐1‐yl)aniline] films on the relative humidity of air was studied. The results of the studies showed the prospects of using thin polymer films in the design of chemical sensors. © 2020 Society of Chemical Industry     

Investigation of novel polyanilines as new antioxidants for ethylene propylene diene monomer rubber composites

Oxidative aging is a significant deterioration process that affects the performance and durability of rubber materials in various applications. Therefore, this study focuses on the development of new antioxidants-based on polyaniline for ethylene propylene diene monomer (EPDM) rubber to enhance its resistance to oxidative aging. The novel polyanilines were prepared using in situ polymerization method and characterized using Fourier transforms infrared (FTIR) and thermogravimetric analysis (TGA). FTIR illustrates the success synthesis of polyanilines as it shows their characteristic functional groups. The thermal stability of the formed polyanilines is discussed through TGA and derivative of thermogravimetry (DTG) curves. The curves prove the good thermal stability of the synthesized polymers. The prepared polyaniline compounds were mixed to carbon black filled-EPDM rubber composites using a roll mill and then vulcanized using sulfur curing process. Accelerated aging tests for the prepared EPDM rubber composites were conducted to evaluate the effectiveness of the antioxidants. Moreover, their impact on rheometer, mechanical, and swelling properties was studied. The results showed that the EPDM samples with the prepared polyaniline compounds exhibited improved oxidative properties compared to the EPDM sample with commercial antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline. These findings suggest that the novel antioxidants have the potential to enhance the durability and performance of EPDM rubber in various applications.     

Polymerization of halogenated anilines by plasma

This work presents an experimental study about the electric conductivity in polyanilines synthesized by plasma obtained from halogenated anilines in which chlorine or iodine atoms are bonded in meta position to the aniline rings. The objective is to study the enhancement of the electric conductivity of these structures due to the addition of electronegative atoms to the polymeric chains. The results show that the halogenated anilines produce polymers with an electric conductivity up to eight orders of magnitude higher than those of the undoped polyanilines, reaching ～10^?4 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4682–4689, 2006     

含氟聚苯胺的合成及其特种功能修饰剂

含氟聚苯胺因其有大π键共轭的聚苯胺骨架结构、强电负性的含氟取代基团,而显示出优异的溶解性、碘掺杂后的导电性和敏感的生物催化性,是聚苯胺家族中很有发展前景的电活性聚合物。该文基于最新研究文献,总结了含氟聚苯胺的合成方法,探讨了含氟聚苯胺的特种修饰功能。着重论述了含氟聚苯胺作为特种功能修饰剂在生物燃料电池、葡萄糖酶生物传感器等领域的研究与应用。指出含氟聚苯胺在特殊环境中的稳定性、电催化增敏性、可再生性等方面都优于无机物和其他导电聚合物,是一种很有发展潜力的功能材料。引用文献17篇。     

Synthesis and Characterization of Lewis Acid Doped Polyaniline and Its Application as Catalysts for Acetalization of Carbonyl Compounds

Lewis acid doped polyanilines are prepared by doping of polyaniline base with Lewis acids. Polyaniline base and Lewis acid doped polyanilines are characterized by physical and spectral methods. They are used as catalysts for the first time for acetalization of carbonyl compounds. The catalyzed acetalization of benzaldehyde with propane-1,2-diol is conducted in excellent yields with simple and more environmentally benign procedure. The use of these doped lewis acid catalysts is feasible because of being ecofriendly, their easy preparation, easy recovery, reusability, and good activity.     

Synthesis and characterization of poly(p-phenylene vinylene) polymers containing the quinoxaline group

Summary Novel poly (p-phenylenevinylene) polymers containing the quinoxaline group were prepared by the Horner-Wadsworth-Emmons reaction of the various diphosphonic acid diethyl ester with a dialdehyde monomer. The spectral properties of products so obtained were characterized by UV-visible and fluorescence spectroscopy. The UV-visible absorbance of these polymers showed absorption bands at ca. 432∼440 nm, which corresponding to the π-π* transition of the conjugated system. Their maximum fluorescence appeared at ca. 488 ∼ 498 nm. The resulting polymers showed greenish blue emission in solution and an orange emission in solid state. Received: 13 December 2002/Revised version: 27 February 2003/ Accepted: 1 March 2003 Correspondence to Jae Yun Jaung     

Chemical synthesis and characterization of self-doped N-propanesulfonic acid polyaniline derivatives

In chemical oxidative homopolymerization of aniline-N-propanesulfonic acid, ammonium persulfate has been used as an oxidant to obtain water-soluble and self-acid-doped polyanilines. Copolymerization of aniline-N-propanesulfonic acid with aniline, using three feed molar ratios of comonomers has been studied, as well. The polymers and copolymers had moderate molecular weights and were soluble in water and polar solvents. They have been obtained in self-acid-doped form, as has been evidenced by UV?CVis spectroscopy, as green-colored materials, and can be de-doped with alkaline solutions. The propanesulfonic groups had not cleaved during the oxidative polymerization and the atomic ratio between nitrogen and sulfur atoms (N/S) was determined by X-ray photoelectron spectroscopy which was consistent with the chemical structure. The chemical structures and morphologies of the homo- and copolymers have been studied by FTIR, ¹HNMR, UV?CVis, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction methods. The X-ray diffraction patterns of the homo- and copolymers have showed a high degree of crystallinity which can be explained by the ionic interaction between propanesulfonate anions and the amine nitrogen atoms of the main chain, resulting in the layering structure of the polyaniline chains. Electrical conductivity of the homopolymer determined at room temperature on pressed pellet was 0.0038?S/cm, while the copolymers show higher conductivities compared with homopolymer.