Polyaniline/Montmorillonite Nanocomposites Obtained by In Situ Intercalation and Oxidative Polymerization in Cationic Modified-Clay (Sodium, Copper and Iron)

Polyaniline/montmorillonite nanocomposites (PANI/M) were obtained by intercalation of aniline monomer into M modified with different cations and subsequent oxidative polymerization of the aniline. The modified-clay was prepared by ion exchange of sodium, copper and iron cations in the clay (Na–M, Cu–M and Fe–M respectively). Infrared spectroscopy confirms the electrostatic interaction between the oxidized PANI and the negatively charged surface of the clay. X-ray diffraction analysis provides structural information of the prepared materials. The nanocomposites were characterized by transmission electron microscopy and their thermal degradation was investigated by thermogravimetric analysis. The weight loss suggests that the PANI chains in the nanocomposites have higher thermal stability than pure PANI. The electrical conductivity of the nanocomposites increased between 12 and 24 times with respect to the pure M and this increase was dependent on the cation-modification. The electrochemical behavior of the polymers extracted from the nanocomposites was studied by cyclic voltammetry and a good electrochemical response was observed.This work was supported by the National Agency for the Development of University Research (ANDRU), the Directorate General of Scientific Research and Technological Development (DGRSDT) of Algeria. Ministerio de Economia y Competitividad and FEDER are also acknowledged (MAT2010-15273). The Generalitat Valenciana is also acknowledged (PROMETEO2013/038)

Reactive Insertion of PEDOT-PSS in SWCNT@Silica Composites and its Electrochemical Performance

Hybrid silica-modified materials were synthesized on glassy carbon (GC) electrodes by electroassisted deposition of sol-gel precursors. Single-wall carbon nanotubes (SWCNTs) were dispersed in a silica matrix (SWCNT@SiO2) to enhance the electrochemical performance of an inorganic matrix. The electrochemical behavior of the composite electrodes was tested against the ferrocene redox probe. The SWCNT@SiO2 presents an improvement in the electrochemical performance towards ferrocene. The heterogeneous rate constant of the SWCNT@SiO2 can be enhanced by the insertion of poly(3,4-Ethylendioxythiophene)-poly(sodium 4-styrenesulfonate) PEDOT-PSS within the silica matrix, and this composite was synthesized successfully by reactive electrochemical polymerization of the precursor EDOT in aqueous solution. The SWCNT@SiO2-PEDOT-PSS composite electrodes showed a heterogeneous rate constant more than three times higher than the electrode without conducting polymer. Similarly, the electroactive area was also enhanced to more than twice the area of SWCNT@SiO2-modified electrodes. The morphology of the sample films was analyzed by scanning electron microscopy (SEM).This research was funded by the Directorate General of Scientific Research and Technological Development (DGRSDT) (Algeria) and by the Ministerio de Ciencia, Innovación y Universidades (MAT2016-76595-R) and by the Conselleria de Educación, Investigación, Cultura y Deporte, Generalitat Valenciana (PROMETEO/2018/087)

Characterization and electrochemical properties of conducting nanocomposites synthesized from p-anisidine and aniline with titanium carbide by chemical oxidative method

A novel polymer/TiC nanocomposites “PPA/TiC, poly(PA-co-ANI)/TiC and PANI/TiC” was successfully synthesized by chemical oxidation polymerization at room temperature using p-anisidine and/or aniline monomers and titanium carbide (TiC) in the presence of hydrochloric acid as a dopant with ammonium persulfate as oxidant. These nanocomposites obtained were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). XRD indicated the presence of interactions between polymers and TiC nanoparticle and the TGA revealed that the TiC nanoparticles improve the thermal stability of the polymers. The electrical conductivity of nanocomposites is in the range of 0.079–0.91 S cm−1. The electrochemical behavior of the polymers extracted from the nanocomposites has been analyzed by cyclic voltammetry. Good electrochemical response has been observed for polymer films; the observed redox processes indicate that the polymerisation on TiC nanoparticles produces electroactive polymers. These nanocomposite microspheres can potentially used in commercial applications as fillers for antistatic and anticorrosion coatings.This work was supported by the National Assessment and Planning Committee of the University Research (CNEPRU), and the Directorate General of Scientific Research and Technological Development (DGRSDT) of Algeria. Financial support from the Generalitat Valenciana (PROMETEO2013/038) is acknowledged

Algerian natural montmorillonites for arsenic(III) removal in aqueous solution

The adsorption of As(III) from aqueous solutions using naturally occurring and modified Algerian montmorillonites has been investigated as a function of contact time, pH, and temperature. Kinetic studies reveal that uptake of As(III) ions is rapid within the first 3 h, and it slows down thereafter. Equilibrium studies show that As(III) shows the highest affinity toward acidic montmorillonite even at very low concentration of arsenic. The kinetics of As(III) adsorption on all montmorillonites used is well described by a pseudo-second-order chemical reaction model, which indicates that the adsorption process of these species is likely to be chemisorption. Adsorption isotherms of As(III) fitted the Langmuir and Freundlich isotherm models well. The adsorption of As(III) is pH-dependent obtaining an optimal adsorption at pH 5. From the thermodynamic parameters, it is concluded that the process is exothermic, spontaneous, and favorable. The results suggest that M1, M2, and acidic-M2 could be used as low-cost and effective filtering materials for removal of arsenic from water.This work has been financed by the Ministerio de Economía y Competitividad and FEDER (project MAT2010-15273). The National Agency for the Development of University Research (CRSTRA), the Directorate General of Scientific Research and Technological Development (DGRSDT) of Algeria

PANI-derived polymer/Al2O3 nanocomposites: synthesis, characterization, and electrochemical studies

This paper presents the physicochemical, conductive, and electrochemical properties of different polyaniline (PANI)-derived polymer/Al2O3 nanocomposites synthesized by chemical oxidation polymerization method carried out in two stages: first, activation of the surface of the Al2O3 nanoparticles by hydrochloric acid and second, polymerization of 2-chloroaniline (2ClANI), aniline (ANI), and the copolymer (2ClANI-ANI) in the presence of Al2O3 by using ammonium persulfate as oxidant in aqueous hydrochloric acid. XRD and TEM results reveal the growth of the polymers on Al2O3 nanoparticles and the formation of PANI-derived polymer/Al2O3 nanocomposites. FTIR and UV-Vis show a systematic shifting of the characteristic bands of the polymers with the presence of Al2O3 nanoparticles. Moreover, these nanoparticles enhance the thermal stability of the polymers, as found by thermogravimetric analysis (TGA). Although the incorporation of Al2O3 nanoparticles reduces the electric conductivity of the polymers, the resulting nanocomposites still keep high conductivities, ranging between 0.3 × 10−2 and 9.2 × 10−2 S cm−1. As a result, the polymer/Al2O3 nanocomposites exhibit a good voltammetric response. All these synergetic features of the nanocomposites are assigned to the effective interaction of the polymers and Al2O3 particles at nanoscale.This work was supported by the National Assessment and Planning Committee of the University Research (CNEPRU number E-03720130015), the Directorate General of Scientific Research and Technological Development (DGRSDT) of Algeria. The financial support from MINECO is also acknowledged (MAT2013-42007-P project)

New poly(o-phenylenediamine)/modified-clay nanocomposites: A study on spectral, thermal, morphological and electrochemical characteristics

This work describes the synthesis and characterization of new poly(o-phenylenediamine (PoPD)/modified-clay nanocomposite materials. For the synthesis, the raw clay (named as Mag) used in this study was from Maghnia (west Algeria), (Mag) clay was ion-exchanged with cobalt(II) sulfate hydrate and copper sulfate. The modified-clays were then dispersed in a oPD monomer-containing acidic solution to carry out in-situ intercalative oxidative polymerization by ammonium persulfate. XRF and XRD characterization reveal the success of ion-exchange to form highly intercalated Mag-Co and Mag-Cu clays. After polymerization, the disappearance of the interlayer-spacing diffraction peak for the PoPD-Mag-Cu and PoPD-Mag-Co nanocomposites points out fully exfoliation of the clay structure. The formation of intercalated PoPD into modified-clay nanocomposites was confirmed by XRD, TEM, TG analysis, FTIR spectroscopy and UV–vis studies. The nanocomposites show optical properties and the redox processes observed by cyclic voltammetry indicate that the reported polymerization into modified-clays leads to electroactive hybrid materials. All these properties make these polymer/clay nanocomposites attractive materials for multiple applications.The authors wish to acknowledge the Directorate General for Scientific Research and Technological Development Algeria. Ministerio de Economía y Competitividad and FEDER is acknowledged for financial support (MAT2016-76595-R)

Synthesis, characterization, and enhanced electrochemical behavior of polypyrrole doped ZrO2–ZnO electrode materials for supercapacitor applications

The polypyrrole@ZrO2–ZnO (PPy@ZrO2–ZnO) electrodes were synthesized using an in situ chemical oxidative method. The samples were characterized by XRD, FTIR, XPS, UV-vis, TGA, and BET. In addition, the electrochemical characteristics of the electrodes are tested by cyclic voltammetry (CV), galvanostatic charge and discharge (G.C.D.), and electrochemical impedance spectroscopy (E.I.S.). The values of the specific capacitances and the energy densities of PPy@ZrO2–ZnO (1.0) and PPy@ZrO2–ZnO (0.5) at a current density of 0.5 A g−1 are recorded as (395.3 F g−1 and 508.5 Wh·kg−1) and (195.3 F g−1 and 351.5 Wh·kg−1), respectively. Furthermore, the electrode stability for the formed samples was also determined, which exhibited specific capacitance retention at 90.2% for PPy@ZrO2–ZnO (1.0) and 82.4% for PPy@ZrO2–ZnO (0.5) after cycling up to 4,000 cycles. This work provides an efficient approach to the potential of the synthesized samples for application as electrodes in a supercapacitor

Reactive Insertion of PEDOT-PSS in SWCNT@Silica Composites and its Electrochemical Performance

Hybrid silica-modified materials were synthesized on glassy carbon (GC) electrodes by electroassisted deposition of sol-gel precursors. Single-wall carbon nanotubes (SWCNTs) were dispersed in a silica matrix (SWCNT@SiO2) to enhance the electrochemical performance of an inorganic matrix. The electrochemical behavior of the composite electrodes was tested against the ferrocene redox probe. The SWCNT@SiO2 presents an improvement in the electrochemical performance towards ferrocene. The heterogeneous rate constant of the SWCNT@SiO2 can be enhanced by the insertion of poly(3,4-Ethylendioxythiophene)-poly(sodium 4-styrenesulfonate) PEDOT-PSS within the silica matrix, and this composite was synthesized successfully by reactive electrochemical polymerization of the precursor EDOT in aqueous solution. The SWCNT@SiO2-PEDOT-PSS composite electrodes showed a heterogeneous rate constant more than three times higher than the electrode without conducting polymer. Similarly, the electroactive area was also enhanced to more than twice the area of SWCNT@SiO2-modified electrodes. The morphology of the sample films was analyzed by scanning electron microscopy (SEM).This research was funded by the Directorate General of Scientific Research and Technological Development (DGRSDT) (Algeria) and by the Ministerio de Ciencia, Innovación y Universidades (MAT2016-76595-R) and by the Conselleria de Educación, Investigación, Cultura y Deporte, Generalitat Valenciana (PROMETEO/2018/087)

Tailoring the properties of polyanilines/SiC nanocomposites by engineering monomer and chain substituents

Hybridization of nanomaterials constitutes an interesting approach to boost and develop novel properties and applications. In this work, different polyaniline (PANI)-derived polymer-SiC nanocomposites have been successfully synthesized by facile surface-initiated polymerization of aniline (ANI) and/or 4-Anisidine (4ANS) on HCl-functionalized SiC. The obtained materials were characterized by different analytical techniques as well as solubility, conductivity and electrochemical tests. The effect of the nature and combination of the substituents in the polymer was analyzed. XRD; thermogravimetry; and vibrational FTIR spectroscopy revealed effective polymerization and interaction between the polymers and the SiC nanoparticles to form PANI-SiC, poly(ANI-co-4ANS)-SiC and P4ANS-SiC nanocomposites. The presence of electron-donating (para) -OCH3 substituents was found to hinder this interaction and/or to retard the polymerization, decreasing the content and crystallinity of the polymer in the nanocomposite. However, the dispersibility of the nanocomposites in different solvents greatly increased, and the electroactive and optical properties were affected. As a result, the poly(ANI-co-4ANS)-SiC nanocomposite exhibits higher dispersibility, lower band gap, similar conductivity and richer electroactivity than PANI-SiC, and an intermediate polymerization yield. Then, engineering the substituents of polymer chains is demonstrated to be an efficient approach to tailor the properties of (PANI)-derived polymer-SiC nanocomposites.The authors wish to acknowledge the directorate General of Scientific Research and Technological Development (DGRSDT) (Algeria)