Chemical Polymerization Of Pyrrole Research Articles

Nickel Oxide Decorated MWCNTs Wrapped Polypyrrole: One Dimensional Ternary Nanocomposites for Enhanced Thermoelectric Performance

AbstractThis study reports on a customized and revised approach to fabricate “nickel oxide decorated multi‐walled carbon nanotubes (MWCNTs) wrapped polypyrrole (PPy)” nanocomposite with enhanced room‐temperature thermoelectric (TE) properties. The nanocomposite is formed through three steps: MWCNTs functionalization via diazonium salt grafting of 5‐amino‐1,2,3‐benzene tricarboxylic acid; in situ generation on their surfaces of NiO nanoparticles with a homogenous distribution; the chemical polymerization of pyrrole using methyl orange as templating and dopant to wrap the MWCNTs‐(COOH)3‐NiO. Various techniques were used as characterization tools, including XRD, TEM, FTIR, Raman, TGA, XPS, and TE measurements. The PPy‐MWCNTs‐(COOH)3‐NiO nanocomposite exhibits significantly higher Seebeck coefficient, electrical conductivity, and power factor than PPy and PPy‐MWCNTs‐(COOH)3. The achieved enhancement in TE properties (figure of merit, ZTPPy‐MWCNTs‐(COOH)3‐NiO=1.51×10−2) is attributed to the presence of NiO, which acts as a dopant and improves the charge carrier density in the nanocomposite. These results offer the potential for waste heat recovery and large‐scale fabrication of high‐performance composites.

Wearable room-temperature ethanol sensor based on Ti3C2Tx/Polypyrrole functionalized face mask for drunk driving monitoring

As one of the most encountered volatile organic compounds (VOCs), ethanol, especially with high blood concentrations, could cause adverse effects such as nausea, vomiting, skin allergies, low blood pressure, low blood sugar, and Parkinson's disease, seriously threatening human health and safety driving. In this study, we demonstrate a wearable ethanol sensor through drop-coating Ti3C2Tx suspension followed by chemical polymerization of pyrrole on a disposable face mask substrate. The as-fabricated PP/Ti3C2Tx/PPy composite sensor exhibited a rapid response/recovery speed (49s/18s), a good sensing response of 76.3 % toward 400 ppm ethanol, an admirable theoretical limit of detection of 2.21 ppm, reliable flexibility, high selectivity, and excellent reproducibility. The outstanding sensing characteristics of the composite sensor are ascribed to the abundant functional groups (e.g., amino groups in PPy, terminal groups in Ti3C2Tx) and the formation of the Schottky junction between Ti3C2Tx and PPy. Moreover, the composite sensor exhibits stable sensing performance around room temperatures (20–40 °C), and even at different bending states (0–150°). In addition, we developed a portable and wearable Bluetooth sensor module for human alcohol breath detection, suggesting the PP/Ti3C2Tx/PPy composite sensor can be used for human drunk driving monitoring and health assessment.

N-Doped carbon nanoparticles on highly porous carbon nanofiber electrodes for sodium ion batteries.

Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber electrodes were successfully synthesized via combining centrifugal spinning, chemical polymerization of pyrrole and a two-step heat treatment. Nanoparticle-on-nanofiber morphology with highly porous carbon nanotube like channels were observed from SEM and TEM images. Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber (N-PCNF) electrodes exhibited excellent cycling and C-rate performance with a high reversible capacity of around 280 mA h g-1 in sodium ion batteries. Moreover, at 1000 mA g-1, a high reversible capacity of 172 mA h g-1 was observed after 300 cycles. The superior electrochemical properties were attributed to a highly porous structure with enlarged d-spacings, enriched defects and active sites due to nitrogen doping. The electrochemical results prove that N-PCNF electrodes are promising electrode materials for high performance sodium ion batteries.

Synthesis and Characterization of Polypyrrole/Fe3O4 Nanocomposites: A Promising Material Against Carbon Steel Corrosion

The use of conducting polymers as coating layers for the protection of surfaces against corrosion represents an important topic for investigation, as reported in the literature. In this work, polypyrrole/Fe3O4 nanoparticles (Fe3O4_NPs/PPy) hybrid nanocomposites (HN) were incorporated as anticorrosive additives in an epoxy paint to protect SAE 1010 carbon steel from corrosion. The HN particles were obtained by chemical polymerization of pyrrole in an aqueous solution in the presence of Fe3O4_NPs and were characterized by infrared absorption spectrophotometry, dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM). The electrochemical impedance spectroscopy (EIS) was used in the analysis of the electrochemical response of the coated surface with and without HN. DLS data showed that the Fe3O4_NPs and Fe3O4_NPs/PPy obtained in solution present average diameters of (19.7 ± 9.6) nm and (63.5 ± 27.7) nm, respectively. TEM images showed Fe3O4_NPs with smaller sizes (10 nm - 30 nm), and that the HN had diameters smaller than 100 nm, consisting of Fe3O4 cores coated with polypyrrole. EIS measurements have shown that the addition of HN to the epoxy paint could improve the efficiency of the anticorrosive coating when compared to the original epoxy paint prepared without any corrosion inhibitor.

Protonated graphitic carbon nitride/polypyrrole/reduced graphene oxide composites as efficient visible light driven photocatalysts for dye degradation and E. coli disinfection

A novel ternary PPy/P-C3N4/r-GO visible light-driven photocatalyst was fabricated via chemical polymerization of pyrrole in the presence of protonated-C3N4/reduced graphene oxide (P-C3N4/r-GO). The resulting PPy/P-C3N4/r-GO composite showed excellent photocatalytic performance under visible light for brilliant red dye (X3B) degradation and E. coli inactivation. An X3B degradation efficiency of 98% was achieved in 60 min, and an E. coli removal efficiency of 100% achieved in 90 min. Moreover, PPy/P-C3N4/r-GO displayed good recycling performance, with 90% efficiency retained over 5×3B photodegradation cycles. A plausible photocatalytic mechanism for the PPy/P-C3N4/r-GO composites was proposed, where p-n heterojunctions formed between P-C3N4 and PPy effective separate charges (photoexcited electrons accumulating in the conduction band of P-C3N4, holes accumulating in the valence band of PPy), with r-GO acting as an electron acceptor and trap. The valence band holes in P-C3N4 directly oxidize X3B, whereas conduction band electrons react with O2 to generate reactive oxygen species (superoxide and hydroxide radicals) which also degrade X3B and can inactivate E. coli. This work thus introduces an efficient metal-free ternary photocatalyst system for environmental applications.

Multifunctional Polypyrrole-silver Coated Layered Double Hydroxides Embedded into a Biodegradable Polymer Matrix for Enhanced Antibacterial and Gas Barrier Properties

In this study, polypyrrole-silver coated layered double hydroxides (LDHs@PPy-Ag) was prepared by chemical polymerization of pyrrole (Py) with silver ions. Silver nanoparticles (AgNPs) could be uniformly reduced onto PPy coatings in situ by redox reaction during simultaneous polymerization process. And LDHs@PPy-Ag/poly(ε-caprolactone) (PCL) nanocomposites were fabricated by solution casting method. It is revealed that spherical AgNPs are loaded on PPy coatings uniformly. Particularly, compared with pure PCL, LDHs@PPy-Ag/PCL nanocomposites with incorporation of only 1 wt% LDHs@PPy-Ag show a 17% increase in tensile strength (36.5 MPa) and a 29% increase in elongation at break (822%). Upon PPy-Ag coatings onto original LDHs, oxygen relative permeability of LDHs@PPy-Ag/PCL nanocomposites decreases to 52% with the same addition. Meanwhile, due to the double antibacterial activity of PPy and AgNPs, the antibacterial rate of LDHs@PPy-Ag reaches 100%. And the corresponding LDHs@PPy-Ag/PCL nanocomposites also show outstanding antibacterial activity. Considering the superiority of their comprehensive performance, antibacterial LDHs@PPy-Ag/PCL nanocomposites can be used further for the application as biodegradable polymeric active packaging materials.

Dielectric barrier discharge plasma induced surface modification of polyester/cotton blend fabrics to improve polypyrrole coating adhesion and conductivity

Electrically conductive polyester-cotton blend fabrics were prepared by plasma pre-treatment followed by oxidative in-situ chemical polymerization of pyrrole. Polyester-cotton blend fabrics were pre-treated with dielectric barrier discharge-atmospheric pressure plasma treatment to improve the binding of polypyrrole coating on polyester-cotton blend substrate. A range of gas mixtures in dielectric barrier discharge were employed to investigate the effects of different gases in plasma induced surface modification to the surface roughness, surface chemistry and hydrophilicity of the fabric. Polyester-cotton blend fabric’s topographical change was observed by means of scanning electron microscopy, wettability changes by wicking height measurements and chemical changes by X-ray photoelectron spectroscopy. Effect of the plasma treatment on binding strength was analyzed by studying abrasion resistance and surface resistivity. Results showed that increase in wettability and surface functionalization by oxygen functional groups contributed to improved adhesion (by 80% up to 2500 abrasion cycles), conductivity (by 65%) and atmospheric degradation (by 68% up to 4 months).

Investigation of in situ formed conductive polymer composite in adhesive matrix

A conductive composite layer on non-conductive substrate was fabricated by chemical polymerization of pyrrole with entrapped ferric chloride (FeCl3) in adhesive polymer matrix. Four different polymer matrices were used for PPy distribution: PVA, PVAc, PVB and PSSA. The surface of our conductive material was characterized using FIB-SEM, FT-IR and XPS analysis. The conductivity of PPy composites were measured using microwave absorption method (frequency range from 8 to 38 GHz), dependence of the adhesive polymer features, and monomer pyrrole concentration. Our study reveals in situ synthesized composites conductivity dependence within different adhesive matrix.

CuO–ZnO p–n junction enhanced oxygen sensing property of polypyrrole nanocomposite at room temperature

In this paper, CuO–ZnO and Polypyrrole (PPy) nanocomposites are synthesized by one pot sol–gel method and chemical polymerization of pyrrole respectively. Polypyrrole loaded p–n junction is formed by adding different weight percentage (10 wt%, 30 wt% and 50 wt%) of CuO–ZnO nanocomposite with PPy and then coated on a substrate using spin coating method. Elemental analysis is done by X-ray Photoelectron Spectroscopy. The morphological studies by High Resolution Transmission Electron Microscopy and Field Emission Scanning Electron Microscopy show the coating of CuO–ZnO nanocomposite on polypyrrole with various weight ratios. The crystal structure and chemical composition of the nanocomposites are characterized by X-ray Diffraction and Fourier Transform Infrared Spectroscopy respectively. From the UV–visible Spectroscopy, the band gap energy of the Polypyrrole is calculated as 3.05 eV. The electrodes are investigated for sensing towards Oxygen, Hydrogen and LPG at room temperature. It reveals that the fabricated electrodes can selectively sense the oxygen gas with improved sensitivity, response time and recovery time. The nanocomposite containing 50 wt% of CuO–ZnO have high response with low response time and recovery time towards oxygen gas in the range of 40–200 parts per million (ppm) at room temperature (30 °C). The sensitivity of the electrodes is highly stable for the period of 50 days.

Annealing led conversion from polypyrrole to carbon nitride nanowires and the fabrication of highly efficient ammonia sensing device

In this work, first of all, polypyrrole (PPy) nanowires have been successfully prepared using template synthesis technique at room temperature by chemical polymerisation of pyrrole within the pores of anodic alumina template. Secondly, the effect of 4 h annealing on morphological, optical and ammonia gas sensing device properties has been studied at 200 °C and 300 °C. The characterization of unanealed and annealed samples was done by using scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and time resolved photoluminescence. IV measurements are done for studying gas sensing device. The SEM confirms the flexible wire-like morphology of unannealed and annealed nanowires whereas XRD investigation shows the amorphous nature of unannealed and annealed nanowires. Characteristic peaks of FTIR confirm the formation of PPy nanowires synthesized at room temperature and transition from polypyrrole to carbon nitride nanowires after annealing PPy nanowires at 200 and 300 °C. The transition from PPy to CNx nanowires after annealing is proved by the characteristic FTIR peaks corresponding to C=C and C=N bond and the time resolved photoluminescence spectra recorded at different wavelengths corresponding to polypyrrole and carbon nitride well known transitions. I–V studies of nanowires show the increase in sensitivity of annealed nanowires towards NH3 at about thousand times than that of unannealed nanowires.

Enhanced electrocatalytic performances of α-Fe2O3 pseudo-nanocubes for oxygen reduction reaction in alkaline solution with conductive coating

Exploring of high-efficient, low-cost and eco-friendly catalysts for oxygen reduction reaction (ORR) is one of the vital issues for fuel cells and metal-air batteries. Herein, α-Fe2O3 pseudo-nanocubes have been synthesized with a facile solvothermal method, and then α-Fe2O3@NC composite catalysts were prepared through chemical polymerization of pyrrole on α-Fe2O3, following with pyrolyzed in nitrogen atmosphere. The synthesized composite catalysts display enhanced ORR catalytic performances, including the positive shifting of the onset potential, improving of the limited current density with long-term stability compared to those of the pristine α-Fe2O3. The enhanced electrocatalytic performances could be ascribed to the low intrinsic and charge transfer resistances, the high content of pyridinic-N and/or FeN, the emergence of graphitic-N and abundant oxygen vacancy on the composite surface. This study here implies that the catalytic activity and stability of metal oxides with poor conductivity could be controlled and improved by simply coating with a nanoscale conductive layer, which shows promising potential applications as precious-metal free catalysts for various metal-air batteries and fuel cells.

Polypyrrole functionalized polyester needlepunched nonwoven fabrics for electro‐magnetic interference shielding

Development of electro‐magnetic shield is an important research area since few decades to protect electronic devices and even human beings from harmful effects of electro‐magnetic rays. Textile based flexible shields are also developed as functionalized materials for this purpose. In this work, needlepunched nonwoven textile based electro‐conductive fabric is prepared by in‐situ chemical polymerization of pyrrole and their effectiveness as electro‐magnetic shield is explored. 33 Box‐Behnken design is used to investigate the influence of manufacturing process parameters of neddlepunched nonwoven fabric such as fabric gsm, punching density and depth of needle penetration on the polypyrrole add‐on, surface resistivity and electro‐magnetic shielding effectiveness. Surface resistivity as low as 18 Ω (with 16.28% polypyrrole add‐on) is obtained for a typical composite fabric. The shielding effectiveness of this fabric is found to be 20.07 dB at 4 GHz frequency. It has been found that the primary mechanism of the shielding is the absorption of electro‐magnetic rays into these composite fabrics rather than reflection from their surface. POLYM. COMPOS., 39:3696–3704, 2018. © 2017 Society of Plastics Engineers

Highly Dispersed Platinum Nanoparticles Anchored on Polypyrrole Nanospheres as Anode Catalyst for Methanol Oxidation Reaction

A novel catalyst of platinum nanoparticles (PtNPs) decorated on polydiallyldimethylammonium chloride (PDDA) functionalized polypyrrole nanospheres (PNS) has been prepared by simple wet-chemical method. PNS with large surface area and high dispersion was prepared by chemical polymerization of pyrrole. PtNPs with uniformed size and high dispersion have been successfully decorated on PDDA functionalized PNS via a sodium borohydride reduction process. The PNS/PtNPs is characterized by transmission electron microscopy, high resolution transmission electron microscopy, energy-dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy and inductively coupled plasma spectrum instrument. The results show that the PtNPs with sizes of approximate 5–6 nm are uniformly dispersed on the surface of PNS. Compared to Vulcan XC-72 carbon black supported same mass PtNPs (XC-72/PtNPs), PNS/PtNPs show larger mass activity (374 mA mg−1) and stronger poisoning-tolerance (If/Ib = 2.85) due to high dispersion of PtNPs on large surface of PNS. The performance indicates that PNS/PtNPs may be an excellent anode catalyst for methanol oxidation reaction.

Colloids of polypyrrole nanotubes/nanorods: A promising conducting ink

Stable colloidal dispersions of polypyrrole (PPy) nanotubes/nanorods were obtained by the chemical polymerization of pyrrole in the presence of methyl orange and poly(N‐vinypyrrolidone). Due to extended morphology of colloidal particles, the films deposited from colloids with PPy nanotubes/nanorods had conductivity two orders of magnitudes higher than those from colloids of ordinary PPy nanoglobules. Dynamic light scattering measurement demonstrated that PPy nanotubes/nanorods have average particles sizes around 500nm with a dispersity index around 0.3. The PPy colloids were stored over 3 months without visible agglomeration or precipitation. UV–vis spectra of PPy nanotubes/nanorods were recorded both in acidic or alkaline media. Raman spectra excited with 785nm excitation laser confirmed the same mechanism of protonation of nanoglobular and nanotubular PPy. The colloid of PPy nanotubes/nanorods also exhibited good electrochemical redox activity, which makes them promising for the deposition of thin conducting layers used in sensors or energy-storage devices. The dispersions were used for the coating of films on poly(ethylene terephthalate) foils.

Electro-conductive Palmyra Fibers By In Situ Polymerization of Pyrrole

ABSTRACTPalmyra (Borassus flabellifer L.) is one of the natural fruit fibers that are available in plenty. This fiber has many advantages, such as biodegradability, renewability, low density, and low cost, which offer greater opportunities to develop new applications. Imparting electrical conductivity to this fiber may open up avenues for various novel applications. In the present study, Palmyra fibers are made electro-conductive by in situ chemical polymerization of pyrrole with FeCl3 oxidant and PTSA dopant. Prepared electro-conductive fibers show average electrical resistivity 2.96 kΩ cm−1. A positive correlation is found between fiber-length and electrical resistance, whereas a negative correlation is found in between fiber-diameter and electrical resistance. FTIR study is conducted to understand the chemical interaction between lingo-cellulose and polypyrrole. Tensile properties and thermal degradation behavior of the prepared electro-conductive fibers are evaluated, and significant deterioration of both tensile properties and thermal stability is observed. Due to this reason, these electro-conductive fibers are unsuitable for mechanical processing and high-tech applications. But the response of these fibers in different pH solution is investigated, and their possible application as a pH sensor has been explored.

Versatile Method for Producing 2D and 3D Conductive Biomaterial Composites Using Sequential Chemical and Electrochemical Polymerization.

Flexible and conductive biocompatible materials are attractive candidates for a wide range of biomedical applications including implantable electrodes, tissue engineering, and controlled drug delivery. Here, we demonstrate that chemical and electrochemical polymerization techniques can be combined to create highly versatile silk-conducting polymer (silk-CP) composites with enhanced conductivity and electrochemical stability. Interpenetrating silk-CP composites were first generated via in situ deposition of polypyrrole during chemical polymerization of pyrrole. These composites were sufficiently conductive to serve as working electrodes for electropolymerization, which allowed an additional layer of CP to be deposited on the surface. This sequential method was applied to both 2D films and 3D sponge-like silk scaffolds, producing conductive materials with biomimetic architectures. Overall, this two-step technique expanded the range of available polymers and dopants suitable for the synthesis of mechanically robust, biocompatible, and highly conductive silk-based materials.

Study of the Efficiency of Polypyrrole/ZnO Nanocomposites as Additives in Anticorrosion Coatings

We synthesized (ZnO nanoparticles)/polypyrrole (ZnO_NPs/PPy) hybrid nanocomposites and used them as additives in an epoxy paint to protect SAE 1020 carbon steel from corrosion. The nanocomposites were obtained by chemical polymerization of pyrrole in aqueous solution and sodium dodecyl sulfate solution containing dispersed ZnO nanoparticles. We characterized the nanoparticles by infrared absorption spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A large disparity in the distribution of ZnO particle sizes became evident from the TEM images, which also show the formation of hybrid nanocomposites consisting of polypyrrole coated ZnO nanoparticles. Electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) tests, which were performed on SAE 1020 carbon steel plates coated with epoxy and ZnO_NPs/PPy, have shown that epoxy paints have their efficiency as anticorrosive coatings significantly improved when ZnO_NPs/PPy hybrid nanocomposites are added to them.

Understanding Ionic Transport in Polypyrrole/Nanocellulose Composite Energy Storage Devices

In this work, we aim to resolve different diffusion processes in polypyrrole/cellulose composites using a combination of impedance spectroscopy and finite element simulations. The computational model involves a coupled system of Ohm's law and Fickian diffusion to model electrode kinetics, non-linear boundary interactions at the electrode interfaces and ion transport inside the porous electrodes, thereby generating the impedance response. Composite electrodes are prepared via chemical polymerization of pyrrole on the surface of a nanocellulose fiber matrix, and the electrochemical properties are investigated experimentally using cyclic voltammetry, impedance spectroscopy and galvanostatic cycling. It is demonstrated that the onset frequency of the capacitive (or pseudocapacitive) process depends on the counter ion electrolyte diffusion, which is modulated by adding different amounts of sucrose to the aqueous electrolyte solution. Consequently, the electrochemical properties can be controlled by diffusion processes occurring at different length scales, and the critical diffusion processes can be resolved. It is shown that under normal operating conditions, the limiting process for charge transport in the device is diffusion within the electrolyte filled pores of the composite electrode.

The composites of silver with globular or nanotubular polypyrrole: The control of silver content

Polypyrrole/silver composites were prepared by chemical polymerization of pyrrole using a mixture of oxidants, silver nitrate and iron(III) nitrate, in aqueous medium at room temperature. The silver content from 0 to 78wt.% was controlled by varying the proportions of both oxidants. Polypyrrole had globular morphology or was obtained as nanotubes in the presence of methyl orange. The morphology of composites was confirmed by transmission electron microscopy. Silver was present as a larger objects of 150–200nm size in globular polypyrrole morphologies or as ≈70nm nanoparticles accompanying the polypyrrole nanotubes. The molecular structure is discussed on the basis of infrared and Raman spectra. Conductivity of the composites of silver with polypyrrole nanotubes is 10–30Scm−1. For composites with globular polypyrrole, the conductivity was lower, 0.17–0.7Scm−1.

Chemical polymerization of pyrrole in the presence of l‐serine or l‐glutamic acid: Electrically controlled amoxicillin release from composite hydrogel

ABSTRACTPolypyrrole (PPy) was chemically prepared from aqueous solutions individually containing l‐serine or l‐glutamic acid, with the addition of ammonium persulfate as the oxidant. The electrical, XPS and FTIR characterizations indicated that the amino acids co‐doped the PPy backbone. TEM revealed that PPy presented a quasi‐spherical morphology with diameters in nanometric scale. The nanostructures of PPy‐glutamic acid efficiently adsorbed therapeutic doses of amoxicillin. Composite hydrogels were obtained by the entrapment of amoxicillin‐loaded PPy in polyacrylamide network. The antibiotic molecules can be subsequently released (or sustained) from composite hydrogel in response to application (or removal) of electrical stimulation. This tuning release profile can lead to promising drug delivery applications such as implantable devices and iontophoretic systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41804.