Electron-Induced Growth Mechanism of Conducting Polymers: A Coupled Experimental and Computational Investigation

Conjugated Polymer Polypyrrole Nanostructures: Synthesis and Photocatalytic Applications

Conjugated polymers (CPs) have been recently widely investigated for their properties and their applications in different fields including photocatalysis. Among the family of CPs, polypyrrole (PPy) has been the most extensively studied owing to its good environmental stability, high electrical conductivity, superior redox properties and easy synthesis. Besides, nanostructured polypyrrole-based nanomaterials are a type of active organic materials for photocatalysis, which is one of their emerging applications. Nanostructuration of polypyrrole can reduce the electron-hole recombination because of short charge transfer distances and reactant adsorption, and product desorption can be enhanced owing to the high surface area offered by nanostructures. This review summarizes synthesis of different nanostructures based on π-conjugated polymer polypyrrole and the latest developments for photocatalytic applications, including degradation of organic pollutants and hydrogen generation.

Gamma rays as an innovative tool for synthesizing conducting copolymers with improved properties

Radiation chemistry was used as an alternative methodology for synthesizing conducting copolymers in water and dichloromethane.

Oxidation of Silver Cyanide Ag(CN)2- by the OH Radical: From Ab Initio Calculation to Molecular Simulation and to Experiment

We investigate the oxidation of silver cyanide AgI(CN)2- in water by the OH radical in order to compare this complex with the free cation Ag⁺ and to measure the influence of the ligands. High-level ab initio calculations of the model species AgII(CN)2· enable the calibration of molecular simulations and the prediction of the oxidized species: AgII(CN)2(H2O)2· and its absorption spectrum, with an intense band at 292 nm and a weaker one at 390 nm. Pulse radiolysis measurements of the oxidation of AgI(CN)2- by the OH radical in water yields a transient species with a broad, intense band at 290 nm and a weaker band at 410 nm at short times after the pulse and a blue shift of the spectrum at longer times. The prediction of the simulations, that the oxidized complex AgII(CN)2(H2O)2· is formed, is confirmed by thermochemistry. Our calculations also suggest that the formation of the OH-adduct is possible only in very basic solution and that the blue shift observed at long times after the pulse is due to disproportionation of the oxidized complex. We also perform molecular simulations of the oxidation of free Ag⁺ cations by the OH radical. The results are compared to that of the literature and to the results obtained with the AgI(CN)2- complex.

Optimal strategy based on radiation chemistry for facile and direct synthesis of poly(3-thiophene acetic acid) polymers in water and dichloromethane

γ-Induced polymerization was used as a novel method to easily synthesize nanostructured PTAA polymers in water and dichloromethane.

Radiolytic Oxidation of Two Inverse Dipeptides, Methionine-Valine and Valine-Methionine: A Joint Experimental and Computational Study

The two inverse peptides methionine-valine (Met-Val) and valine-methionine (Val-Met) are investigated in an oxidative radiolysis process in water. The OH radical yields products with very different absorption spectra and concentration effects: Met-Val yields one main product with a band at about 400 nm and other products at higher energies; there is no concentration effect. Val-Met yields at least three products, with a striking concentration effect. Molecular simulations are performed with a combination of the Monte Carlo, density functional theory, and reaction field methods. The simulation of the possible transients enables an interpretation of the radiolysis: (1) Met-Val undergoes an H atom uptake leaving mainly a neutral radical with a 2-center-3-electron (2c-3e) SN bond, which cannot dimerize. Other radicals are present at higher energies. (2) Val-Met undergoes mainly an electron uptake leaving a cation monomer with a (2c-3e) SO bond and a cation dimer with a (2c-3e) SS bond. At higher energies, neutral radicals are possible. This cation monomer can transfer a proton toward a neutral peptide, leaving a neutral radical.

Mechanism of (SCN)2·- Formation and Decay in Neutral and Basic KSCN Solution under Irradiation from a Pico- to Microsecond Range

The detailed mechanism of the reaction between SCN^- and the OH^· radical and the formation of the dimer radical (SCN)₂^·- are studied by picosecond pulse radiolysis. First, concentrated SCN^- solutions are used to observe directly the formation and decay of SCNOH^·- in neutral and basic solutions. Then, the spectro-kinetic data, constituting a large matrix of data of the absorbance at different times and different wavelengths, obtained by pulse radiolysis measurements with a streak camera, in neutral and basic SCN^- solutions, are analyzed simultaneously. Data analysis allowed us to deduce the absorption spectra of different radicals with their extinction coefficient and also to determine the rate constants of different reactions involved in the formation and decay of (SCN)₂^·-. Molecular simulations of the absorption spectra of the different species were also performed. The absorption spectrum of the radical SCN^· is determined and is found to be different than that reported previously. It does not present a Gaussian shape centered at 330 nm; the absorption around 310 and 380 nm is not negligible. In addition, in a solution at pH 13, it is found that the (SCN)₂^·- radical is paired with an alkaline cation, inducing a blueshift of the absorption band compared to the free (SCN)₂^·-. Finally, the presence of K⁺ cations catalyzes the disproportionation reaction of (SCN)₂^·- and affects the kinetics.

An alternative radiolytic route for synthesizing conducting polymers in an organic solvent

We originally used radiation chemistry as an alternative methodology for synthesizing conducting polymers in an organic solvent.

Nanostructured conducting polymers for energy applications: towards a sustainable platform

Recently, there has been tremendous progress in the field of nanodimensional conducting polymers with the objective of tuning the intrinsic properties of the polymer and the potential to be efficient, biocompatible, inexpensive, and solution processable. Compared with bulk conducting polymers, conducting polymer nanostructures possess a high electrical conductivity, large surface area, short path length for ion transport and superior electrochemical activity which make them suitable for energy storage and conversion applications. The current status of polymer nanostructure fabrication and characterization is reviewed in detail. The present review includes syntheses, a deeper understanding of the principles underlying the electronic behavior of size and shape tunable polymer nanostructures, characterization tools and analysis of composites. Finally, a detailed discussion of their effectiveness and perspectives in energy storage and solar light harvesting is presented. In brief, a broad overview on the synthesis and possible applications of conducting polymer nanostructures in energy domains such as fuel cells, photocatalysis, supercapacitors and rechargeable batteries is described.

Recent Advances in Nanostructured Conducting Polymers: from Synthesis to Practical Applications

Conducting polymers (CPs) have been widely studied to realize advanced technologies in various areas such as chemical and biosensors, catalysts, photovoltaic cells, batteries, supercapacitors, and others. In particular, hybridization of CPs with inorganic species has allowed the production of promising functional materials with improved performance in various applications. Consequently, many important studies on CPs have been carried out over the last decade, and numerous researchers remain attracted to CPs from a technological perspective. In this review, we provide a theoretical classification of fabrication techniques and a brief summary of the most recent developments in synthesis methods. We evaluate the efficacy and benefits of these methods for the preparation of pure CP nanomaterials and nanohybrids, presenting the newest trends from around the world with 205 references, most of which are from the last three years. Furthermore, we also evaluate the effects of various factors on the structures and properties of CP nanomaterials, citing a large variety of publications.

Poly(3,4-ethylenedioxythiophene) (PEDOT) infused TiO2 nanofibers: the role of hole transport layer in photocatalytic degradation of phenazopyridine as a pharmaceutical contaminant

PEDOT infused TiO₂ nanofibers exhibit enhanced photocatalytic performance by improved hole transfer for the degradation of PAP.