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[Polymers and Polymeric Composites: A Reference Series] Functional Polymers || Conducting Polymer Nanocomposites as Gas Sensors
摘要： The great concerns regarding environmental and living beings protection together with the widespread requirements for highly accurate process monitoring have highlighted the need for the development of new and sensitive sensors. Conducting polymers and their nanocomposites have been used widely as sensing materials owing to their special redox chemistry. The electrical properties can be controlled easily by doping and undoping processes resulting into the generation of conducting and nonconducting states, respectively. The electrical conductivity also depends on the type and amount of filler (nanosize filler in some cases) used which produces the positive or negative carriers responsible for the conduction. Any type of interaction of these polymers that affects the number and movement of charge carriers affects the conductivity and is the main principle behind the gas sensing characteristics. Advances in nanotechnology allows for the fabrication of various conducting polymer nanocomposites using different techniques. Conducting polymer nanocomposites have high surface area, small dimension, and show enhanced properties, making them suitable for various sensor devices. This chapter presents the different types of gas sensors based on the conducting polymer (polyaniline, polypyrrole, and polythiophene)-based nanocomposites, their progress, and future scope of ongoing research in this research area. The factors that affect the performance of the gas sensors and the chemistry of the sensing process are also addressed.
关键词： Conducting polymers,Undoping,Doping,Polythiophene,Environmental conditions,Polypyrrole,Surface area,Nanocomposites,Polyaniline,Gas sensors
更新于2025-09-10 09:29:36
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || Polymer Electrodes: Preparation, Properties, and Applications☆
摘要： Good electric conductivity acquired through redox processes is the flagship property of polymers containing extended conjugated p-electron systems. It was discovered by Heeger and MacDiarmid in polyacetylene synthesized by Shirakawa’s method. Polyacetylene is chemically the simplest example amongst a vast collection of such materials, but it is environmentally unstable. Instead, polyheteroaromatics, such as polypyrrole and polythiophene, and polyaniline (polyphenylamine), as well as their derivatives, are of foremost interest because of applications in analytical sensors, power sources, separation devices, optoelectronic devices, and controllable platforms of chemical and biochemical reactions.
关键词： Preparation,Applications,Polythiophene,Polypyrrole,Properties,Polymer Electrodes,Conducting Polymers,Polyaniline
更新于2025-09-10 09:29:36
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Ordered polypyrrole nanorings with near-infrared spectrum absorption and photothermal conversion performance
摘要： Ordered polypyrrole nanorings (PPy NRs) morphology is synthesized by direct chemical oxidative polymerization using the composite of cetrimonium cations and peroxydisulfate anions as the soft template. The size of PPy NRs is 200nm, and the diameter of single wire is 50-70nm. These ordered nanorings display strong near-infrared (NIR) spectrum absorption and excellent photothermal conversion performance. The temperature of PPy NRs / polydimethylsiloxane (PDMS) composites is up to about 170°C under irradiation with an 808 nm laser with power of 2.2W. More important, the NIR-response materials PPy NRs /vitrimer can induce the performances of shape memory, reshaping, welding, and self-healing under different NIR irradiation power. This study designs a unique and ordered nanostructure, which achieving outstanding photothermal conversion performance.
关键词： polypyrrole,nanorings,photothermal conversion,near-infrared,vitrimer
更新于2025-09-10 09:29:36
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Direct Growth of a Polypyrrole Aerogel on Hollow CuS Hierarchical Microspheres Yields Particles with Excellent Electromagnetic Wave Properties
摘要： A current hot topic in polymer science is the development of electromagnetic wave-absorbing materials with desired properties (i.e., proper impedance matching and strong attenuation capability), but it presents a considerable challenge. In this work, solvothermal, and self-assembled polymerization were employed for the controlled fabrication of a uniform polypyrrole (PPy) aerogel coated on hollow CuS hierarchical microspheres (CuS@PPy). The PPy coating thickness of the heterostructure could be tuned by varying the feeding weight ratios of CuS/pyrrole monomer. The electromagnetic wave absorption properties of the CuS@PPy composites were estimated to be in the frequency range 2–18 GHz. The as-prepared Sample B (fabricated by the addition of 35 mg CuS) showed a maximum re?ection loss (RL) of ?52.85 dB at a thickness of 2.5 mm. Moreover, an ultra-wide effective bandwidth (RL ≤ ?10 dB) from 9.78 to 17.80 GHz (8.02 GHz) was achieved. Analysis of the electromagnetic properties demonstrated that the CuS@PPy had a remarkable enhancement compared to pure CuS platelet-based spheres and pure PPy, which can be attributed to the increased relatively complex permittivity and the promoted dielectric loss by the intense interfacial dielectric polarizations. We believe that the as-fabricated CuS@PPy can be a good reference for the fabrication of lightweight and optimal broadband absorbers.
关键词： core–shell,dielectric loss,electromagnetic absorption,polypyrrole
更新于2025-09-10 09:29:36
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Construct 3D Pd@MoS2-conjugated polypyrrole framworks Heterojunction with unprecedented photocatalytic activity for Tsuji-Trost reaction under visible light
摘要： Site-selective coupling of two photochemical system and one electron-transfer system to realize efficient charge separation and light absorption affords a promising route to enhance the photocatalytic efficiencies of semiconductors. To date, however, how to develop 3D porous multicomponent heterojunction systems for solar energy conversion in the visible and near-infrared (NIR) light region still remains a significant challenge. Here we report a simple technique for forming 3D Pd@MoS2-conjugated polypyrrole framworks (Pd@MoS2CPFs), in which two visible-light-active components (MoS2 nanosheets and polypyrrole) and the electron-transfer system (Pd) are spatially fixed, and the uniform Pd NPs are anchored in the MoS2CPFs. This 3D porous system exhibits good structural stability, high pore volume (0.31 cm3g-1), high surface area (105.24 m2/g), improved light absorption, and a long living electron-hole pair at the Pd@MoS2CPFs interface. Unexpectedly, we first found that the formed Pd@MoS2CPFs exhibited excellent photocatalytic activity and long-term stability for the direct Tsuji-Trost reaction between allylalcohol and 1,3-dicarbonyl under visible light at room temperature, far exceeding those of the single- and two-component systems, as a result of vectorial electron transfer driven by the one-step excitation of polypyrrole and MoS2. These results provide a promising new avenue in the design and fabrication of unique 3D porous multicomponent heterojunction for visible-light-induced efficient artificial photosynthetic systems.
关键词： MoS2,Pd nanoparticles,Tsuji–Trost reaction,synergic photocatalysis,polypyrrole
更新于2025-09-09 09:28:46
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Controllable coating polypyrrole on silicon carbide nanowires as a core-shell nanostructure: a facile method to enhance attenuation characteristics against electromagnetic radiation
摘要： Continuous polypyrrole (PPy) shells were coated on silicon carbide (SiC) nanowires to form core-shell nanostructures and the thicknesses of the shells were efficiently tuned through controlling the rate of polymerization. Compared with the composites loaded with pure SiC nanowires, the values of ε′ and ε′′ for the composites loaded with PPy@SiC nanowires were strengthened remarkably along with the increased thickness of the shells. The electromagnetic absorption (EA) bandwidth lower than ?10 and ?20 dB can be monitored in the area of 3.67-18.00 and 4.13-18.00 GHz, when 5 wt% of PPy@SiC nanowires were loaded in the composite. Meanwhile, the effective EA bandwidth can reach 6.88 GHz and the strongest reflection loss is ?58.6 dB.
关键词： dielectric properties,polypyrrole,silicon carbide nanowires,core-shell nanostructures,electromagnetic absorption
更新于2025-09-04 15:30:14
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Visible–light driven photocatalytic degradation of bisphenol-A using ultrasonically synthesized polypyrrole/K-birnessite nanohybrids: Experimental and DFT studies
摘要： Although manganese oxides are known for their semiconductor characteristics, the photocatalytic performance of conducting polymer intercalated K-Birnessite (K-Bi) has not been explored till date. With the view to design a visible light driven organic–inorganic hybrid photocatalyst for rapid degradation of Bisphenol A (BPA), the present work reports the ultrasound-assisted green synthesis of K-Bi/polypyrrole (Ppy) nanohybrids. The loading of Ppy in K-Bi was confirmed by thermogravimetric analysis while the formation of organic–inorganic hybrid was confirmed by infrared spectroscopy. K-Bi revealed a band gap of 2.8 eV while for the nanohybrids it was found to be ranging between 2.4 and 1.6 eV. X-ray diffraction studies confirmed partial intercalation of Ppy chains in the inter-layer space of K-Bi. High resolution transmission electron microscopy and scanning electron microscopy studies showed mixed morphology of K-Birnessite/Ppy nanohybrids. Rapid degradation of BPA was observed under visible irradiation in presence of K-Bi/Ppy nanohybrids and almost 90% degradation of 20 mg/L BPA solution was achieved within 120 min. The degradation was found to follow pseudo-first order kinetics and the degraded fragments were identified using liquid chromatography-mass spectrometry. Degradation pathway was proposed based on density-functional theory calculations of fukui index predicting the radical easy-attacking (f0) and (f-) sites in BPA.
关键词： DFT calculations,Degradation kinetics,Photocatalysis,Manganese oxide,Polypyrrole
更新于2025-09-04 15:30:14