Samy Remita

National Conservatory of Arts and Crafts | CNAM

Nowadays growing attention is given to the design and development of novel interpenetrating polymer networks (IPN) from the combination of hydrogel polymers loaded with natural clay. In this work, we used the eco-friendly IPN strategy to develop novel hydrogel biocomposite beads, made of alginate (ALG), with improved clay dispersion, higher pH sens...

In this paper, we present a novel approach for the preparation of reduced Graphene oxide (rGO) through the radiolytical reduction of commercial Graphene Oxide (GO). The method is a highly...

Conjugated polymers have emerged as very active photocatalysts under visible light. Among these materials, nanostructured polypyrrole (PPy) has recently been used as photocatalyst for degradation of environmental pollutants under UV as well as visible light. In the present study, we specifically explored the photocatalytic activity of conducting PP...

This chapter describes the original and successful use of high energy radiations in the field of conducting polymers (CPs) synthesis. Indeed, these conjugated polymers can be easily and directly produced by means of radiation‐induced (by gamma rays or accelerated electrons) polymerization of various organic monomers dissolved either in aqueous solu...

In the present study, copolymers of Pyrrole (Py) with different co-monomers (thiophene derivatives) were originally polymerized through two radiolytic approaches: water radiolysis and dichloromethane radiolysis. This method can be easily...

Conjugated polymers have emerged as very active photocatalysts under visible light. Among these materials, nanostructured polypyrrole (PPy) has recently been used as photocatalyst for degradation of environmental pollutants under UV as well as visible light. In the present study, we specifically explored the photocatalytic activity of conducting PP...

As alternative radiolytic approach, the synthesis of P3HT was made possible thanks to the oxidation of 3HT monomers by chloromethyl and dichloromethyl radicals or by their corresponding peroxyl radicals in situ produced by dichloromethane solvent radiolysis. Under two different experimental conditions, in oxygen-free solution and in oxygen-saturate...

In this work, synthesis of nanostructured conducting poly(3-thiophene acetic acid) (PTAA) polymers was developed by means of gamma-induced oxidative polymerization of TAA monomers dissolved either in water or in dichloromethane....

In this work, conducting polymers were synthesized for the first time in acidic aqueous solutions by means of γ-irradiation. Poly(3,4-ethylenedioxythiophene) (PEDOT) polymers were prepared under N2O atmosphere in the presence of highly concentrated hydrochloric acid (HCl) at pH 0, thanks to the oxidation of 3,4- ethylenedioxythiophene (EDOT) monome...

Conjugated polymer nanostructures (CPNs) emerge as a new class of photocatalysts for organic pollutant degradation under UV and visible light. Polyprrole (PPy), as a conjugated polymer, exhibits a wide range of applications. We present here the first demonstration of employing pure PPy nanostructures as a very efficient photocatalyst for water depo...

A new and simple promising method for synthesizing conducting polymers in organic solvents was successfully achieved for the first time thanks to the oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) monomers dissolved in dichloromethane by means of gamma-radiolysis. EDOT polymerization was controlled and optimized thanks to the study o...

A cellulose-based adsorbent was originally prepared in ionic liquid and used for Cr (VI) ion removal. The preparation methodology involved chemical induced grafting of styrene onto microcrystalline cellulose (MCC), followed by chloroacetylation, amination and protonation processes in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) ionic liquid used...

Conjugated polymer nanostructures have recently emerged as a new class of very active photocatalysts under solar light. Poly(3-hexylthiophene) (P3HT) is one of the commonly used conjugated polymers for photovoltaics applications . P3HT nanostructures synthesized in soft templates provided by hexagonal mesophases show high photocatalytic activity fo...

An original methodology based on radiation chemistry was used for the synthesis of hybrid organic–inorganic composites in aqueous solution. Starting from 3,4-ethylenedioxythiophene (EDOT) monomers and silver perchlorate salt, the preparation of PEDOT/Ag composites, made of poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers and silver nano...

Liquid crystal (LCs) is the state of matter that exhibits properties between a conventional liquid and solid crystals. Liquid crystals mainly can be classified into two types: thermotropic and lyotropic liquid crystals. A thermotropic liquid crystal shows properties that are dependent on temperature conditions. On the other hand in lyotropic liquid...

The development of visible-light responsive photocatalysts would permit more efficient use of solar energy, and thus would bring sustainable solutions to many environmental issues. Conductive polymers appear as a new class of very active photocatalysts under visible light. Among them poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most promi...

Oil-swollen hexagonal mesophases resulting from the surfactant mediated self-assembly of a quaternary mixture of water, surfactant, co-surfactant, and oil, are versatile templates to synthesize anisotropic nanomaterials. Poly(diphenylbutadyine) (PDPB) polymer nanofibrous network structures were produced in the oil tubes of the mesophases by photo-i...

Synthesis of conducting poly(3,4-ethylenedioxythiophene), PEDOT, is achieved through an original reduction-polymerization route: γ-radiolysis of aqueous solutions containing EDOT monomers under N2 atmosphere. According to UV-vis absorption spectrophotometry and ATR-FTIR spectroscopy, reduction of EDOT is initiated by hydrated electrons produced by...

Pulse radiolysis was used to study the mechanism of HO.-induced polymerization of poly(3,4-ethylenedioxythiophene), PEDOT, in aqueous solution. A step-by-step mechanism has been found which involves a recurrent oxidation process by HO. hydroxyl radicals produced by water radiolysis. Besides, the cation radical, EDOT.+, has been proposed as the prom...

Visible-light-responsive photocatalysts can directly harvest energy from solar light, offering a desirable way to solve energy and environment issues1. Here, we show that one-dimensional poly(diphenylbutadiyne) nanostructures synthesized by photopolymerization using a soft templating approach have high photocatalytic activity under visible light wi...

Oil-swollen hexagonal mesophases resulting from the surfactant mediated self-assembly of a quaternary mixture of water, surfactant, co-surfactant, and oil, are versatile templates to synthesize anisotropic nanomaterials. Poly(diphenylbutadyine) (PDPB) polymer nanofibrous network structures were produced in the oil tubes of the mesophases by photo-i...

In this study, a novel and extremely facile method for the synthesis of conducting polypyrrole (PPy) was achieved in aqueous solution. This radiolytic method is totally free of template and environmentally friendly compared with traditional chemical methods. According to ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infrared (FTIR...

Synthesis of conjugated poly(3,4-ethylenedioxythiophene) (PEDOT) polymers is achieved through the radiolysis of N2 O-saturated aqueous solutions of 3,4-ethylenedioxythiophene by using two different oxidizing species: HO(.) (hydroxyl) and N3 (.) (azide) radicals. Both oxidative species lead to self-assembled polymers that are evidenced in solution b...

ag We describe a single step preparation of nanostructures of poly(3,4-ethylenedioxythiophene), PEDOT, in the hydrophobic domains of cationic surfactant-based hexagonal mesophases via chemical oxidative polymerization of EDOT monomers using FeCl 3 as an oxidizing agent. After polymerization, the hexagonal structure of the mesophases is preserved as...

Chemical sensor based on molecularly imprinted conducting polymers (MICP) is described. Polythiophenes – acetic acid thiophene MICP films with different thicknesses have been electrosynthesized over the sensing area of an original electrochemical surface acoustic wave sensor (ESAW). To investigate the sensing properties of the developed sensor, ele...

Starting from thiophene-based functional monomers (FM), namely, TMA, TAA, TMeOH, EDOT, and Th, bonded to atrazine (ATZ) target molecules into FM/ATZ prepolymerization dimers in acetonitrile solutions, differently functionalized molecularly imprinted conducting polymers (FM-MICP) are electrosynthesized and then washed and used as sensitive layers fo...

Herein we report the development of a chemical sensor based on Molecularly Imprinted Conducting Polymers (MICP) electrosynthesized over the sensing area of a lithium tantalate Surface Acoustic Wave (SAW) sensor. In our conditions, MICP films operate as electroactive receptor layers dedicated to the detection of atrazine target molecules. Film forma...

Sensitive layers based on conducting homopolymer [poly(3,4-ethylenedioxythiophene), denoted PEDOT] and copolymers [molecularly imprinted and non-imprinted poly(EDOT-co-3-thiophene acetic acid), denoted MICP and NICP, respectively] are electrosynthesized on gold substrates and used for the electrochemical detection of atrazine. These layers are char...

Lipids are the essential components of cell membranes and lipoproteins. Their peroxidation plays an important role in numerous pathologies in which oxidative stress is involved. Lipid peroxidation occurs through a chain reaction that contributes to membrane damage in cells. It results in the conversion of fatty acids to polar hydroperoxides and lea...

An original electrochemical sensor based on molecularly imprinted conducting polymer (MICP) is developed, which enables the recognition of a small pesticide target molecule, atrazine. The conjugated MICP, poly(3,4-ethylenedioxythiophene-co-thiophene-acetic acid), has been electrochemically synthesized onto a platinum electrode following two steps:...

Molecular dynamics simulations were used to explore the structure of linoleic acid (LIN) micelles made up with 60 monomers in explicit water. To examine micellar properties, two approaches were considered using “preformed” and “self-aggregated” micelles. Our results demonstrate the quickness of the process of monomers aggregation. After 10 ns, both...

Grazing incidence x-ray irradiation of a Langmuir monolayer deposited at the interface between an aqueous silver salt solution and the air leads to the formation of a metallic silver layer of thickness about 4.5 nm, in agreement to the x-ray penetration depth at the air – water interface. Moreover using the scattering and fluorescence induced by th...

We show that X-ray irradiation of metal salt aqueous solutions in the absence of any stabilizer leads to the synthesis of metal nano-particles, similarly to γ-ray irradiation. The chemical route is the reduction of silver metal ions induced by radiolysis of water. Moreover, X-rays used for the synthesis allow following in situ the formation of silv...

We combine the self-assembly properties of amphiphilic molecules with the radiolysis method to produce specific sizes and shapes of metallic nano-objects. Radiolysis is used to synthesize core--shell structures consisting of nanometric linoleate spherical micelles as the core and silver as the shell. The validity of the technique is asserted by cry...

Self-assemblies of a calix[6]arene (1) functionalized at the small rim by three imidazolyl arms and at the large rim by three hydrophilic sulfonato groups have been studied in water. Transmission electron microscopy, atomic force microscopy, and in situ dynamic light scattering showed that 1 forms multilamellar vesicles at a concentration equal to...

Synthesis of metal nanoshells around organic micelles is achieved through radiolysis of aqueous solutions of surfactant self-assembled in spherical micelles and metal ions. The formation of the metal nanoshells is evidenced by UV-visible spectroscopy and Small Angle X-ray Scattering.

Archidonate peroxidation has been studied using HO* radicals radiolytically generated as initiators of this process. Irradiated aqueous solutions of arachidonate (between 0.01 and 25 mM at pH 10.5) have been characterised by means of conjugated dienes measurement (234 nm-absorption spectroscopy) and hydroperoxide detection (high-performance liquid...

The present study was aimed at determining the peroxidation of model membranes constituted of liposomes of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine (PLPC) submitted to hydroxyl free radicals (generated by gamma-radiolysis) attack. Liposomes of PLPC were prepared using the sonication technique, and dynamic light-scattering (DLS) measureme...

The radiolysis yields in pure water were determined using nanosecond pulse radiolysis using high linear energy transfer (LET) particles (1 ns pulses of high energy 1 GeV carbon ion beam). The main characteristics of this experiment were the nanosecond time resolution with heavy ion beam and the single value of LET along the ion track: 27 eV/nm. The...

An application of the radiolysis method using X-ray synchrotron beam is developed as a novel approach to the synthesis of metal-organic films with controlled shapes and thickness. We demonstrate that a Langmuir monolayer deposited onto a silver ion-containing subphase, irradiated by an incident beam impinging below the critical angle for total refl...

The mechanism of the •OH-induced oxidation of N,S-diacetyl-l-cysteine ethyl ester (SNACET) was investigated in aqueous solutions using pulse radiolysis and steady-state γ-radiolysis combined with chromatographic and ESR techniques. The reaction of hydroxyl radicals with SNACET at slightly acidic to neutral pH results in the degradation into acetald...

Lipids are the essential components of cell membranes and lipoproteins. Their peroxidation plays an important role in numerous pathologies in which oxidative stress is involved. Lipid peroxidation occurs through a chain reaction that contributes to membrane damage in cells. It results in the conversion of fatty acids to polar hydroperoxides and lea...

Aqueous solutions of linoleic acid were irradiated in air with gamma-rays of 137Cs. High pressure liquid chromatography (HPLC) was been used to separate and measure the production of hydroperoxides. The results obtained after reverse phase chromatography, associated with a microperoxydase for hydroperoxide detection, indicate the presence of two di...

Aqueous solutions of linoleic acid were irradiated in air with gamma -rays of Cs-137. High pressure liquid chromatography (HPLC) was been used to separate and measure the production of hydroperoxides. The results obtained after reverse phase chromatography, associated with a microperoxydase for hydroperoxide detection, indicate the presence of two...

Peroxidation of unconjugated polyunsaturated fatty acids such as linolenic acid proceeds through a free radical chain mechanism and is accompanied by the formation of conjugated dienes such as hydroperoxides. In an investigation of radiation-induced oxidation of aqueous linolenate, we have measured two indexes of peroxidation: (1) conjugated dienes...

Irradiating mixed aqueous solutions containing PtIICl2−4 or PtIVCl2−6 and AuIIICl−4 ions leads to bimetallic clusters. The bimetallic character is evidenced by X microanalysis measurement and the absorption surface plasmon spectra. The spectrum of such sols is different from those of the pure metals. The preferential formation of the gold particles...

Peroxidation of polyunsaturated fatty acids such as linoleic acid in aqueous micellar solution proceeds through a free-radical chain mechanism and is accompanied by the formation of conjugated dienes, some in the form of hydroperoxides. In the course of an investigation of radiation-induced oxidation of aqueous sodium linoleate, we have measured th...

Pulse radiolysis is used to determine the absorption spectra of the transient species formed during the decay of the hydrated electron in an aqueous solution of AgI1(NH3)2+. The absorption spectrum attributed to Ag01(NH3)2 presents three peaks at 345, 385, and 435 nm. A theoretical estimation of the redox potential of the couple AgI1(NH3)2+/Ag01(NH...

The first steps of silver clusters nucleation have been studied by pulse radiolysis in the presence of EDTA and CN- ligands. The successive rate constants and the transient absorption spectra corresponding to Ag10 and Ag2+ have been determined. It has been found that Ag10 and Ag2+ were complexed by the ligands. In addition to the usual charge-trans...

Irradiating aqueous solutions containing both Ag2SO4 and K2PtCl4 leads to intermetallic aggregates of various sizes according to the stabilizing agent: polyvinylalcohol, polyacrylic acid or polyacrylate. In the last case, the particle diameter is 1.5 nm. The bimetallic character is evidenced in all cases by the spectral changes of such sols compare...

The influence of a ligand L on the transient species issued from the silver ion reduction has been studied by pulse radiolysis. The optical properties of the silver atom and of the cation Ag2+ depend on the solvent and also on the ligand, CN-, EDTA, or NH3, by which they are complexed. The bands of the complexed species are markedly shifted relativ...

The redox potential of the Ag1I(CN)2-/Ag10(CN)22- couple in aqueous solution is evaluated with the aid of a thermodynamical cycle including gas phase and solvated species. We use the SCF method for the determination of the electronic structure of the gaseous species and the cavity model for the solvation effect. We find the value -2.6 V/NHE, which...

Silver oligomers prepd. by radiolysis in aq. soln. in the presence of polyacrylate and absorbing at .apprxeq.290 nm have been imaged by STM in air after being deposited on a HOPG (highly oriented pyrolytic graphite) surface. Clear images with at. resoln. are obsd., showing flat clusters of 0.7 nm. Each cluster contains seven (or possibly eight) ato...

Various metal aggregates prepared using ionizing radiation were studied by microscopy techniques. A metal deposit onto a carbon felt obtained from solutions containing Pt and Ru was shown to consist of nanometric particles containing both metals. Another study deals with a subnanometric silver aggregate. The nuclearity of the aggregate was studied...