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Electrically conductive Polypyrrole-zirconium(IV)selenoiodate (PPy/ZSI) cation exchange nanocomposite have been synthesized by chemical oxidative polymerization of polypyrrole (PPy) in the presence of zirconium(IV)selenoiodate (ZSI) by sol-gel method. The formation of PPy/ZSI nanocomposite was characterized by fourier transform infra-red spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray (EDX) and thermogravimetric analysis (TGA). The ion exchange capacity (IEC) and electrical conductivity of the nanocomposite was found to be 2.49 meq/g and 0.436 S/cm respectively. The nanocomposite showed appreciable isothermal stability in terms of DC electrical conductivity retention under ambient condition up to 130 °C. In addition, the cation exchange nanocomposite based sensor for detection of formaldehyde vapors was fabricated at room temperature. It was revealed that the resistivity of the nanocomposite increases on exposure to higher percent concentration of formaldehyde at room temperature (25 °C), also the sensor exhibited good reversible response towards formaldehyde vapors ranging from 5 to 7%. The present study may serve as a basis for designing other smart materials for formaldehyde sensors. [ABSTRACT FROM AUTHOR]

Highlights: [•] Kinetics studies envisage the mechanism of ion exchange on the surface of nanocomposite PANI-ZTP. [•] Exchange process governed by particle controlled diffusion phenomenon which is faster than the film diffusion. [•] Self-diffusion co-efficient of Ba2+ is highest because of greater ionic size. [•] Activation energy is calculated by using verified and validated Arrhenius equation. [•] Negative values of ΔS° indicate the presence of more active exchangeable sites in the proposed nanocomposite. [ABSTRACT FROM AUTHOR]

Abstract: Electrically conductive poly(3-methythiophene)-titanium(IV)molybdophosphate (P3MTh–TMP) cation exchange nanocomposites have been synthesized for the first time by in situ chemical oxidative polymerization of 3-methythiophene (3MTh) in the presence of titanium(IV)molybdophosphate (TMP). Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA) and elemental analysis were used to characterize P3MTh–TMP cation exchange nanocomposites. The characterization results confirmed that there is a strong interaction between P3MTh and TMP particles and the nanocomposites showed higher thermal stability than pure P3MTh. The composite showed good ion-exchange capacity, electrical conductivity and isothermal stability in terms of DC electrical conductivity retention under ambient condition below 100°C. A cation exchange nanocomposite based sensor was fabricated for the detection of aqueous ammonia, it was found that the resistivity of the nanocomposites increases on exposure to ammonia at room temperature (25°C) and there showed a linear relationship between the responses and the concentration of ammonia. [Copyright &y& Elsevier]

Abstract: Electrically conductive Poly-o-toluidine–titanium(IV)phosphate (POT–TiP) cation exchange nanocomposite was synthesized by sol–gel mixing of organic polymer (Poly-o-toluidine) into inorganic precipitate of titanium(IV)phosphate (TiP). The material was characterized by using transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The humidity sensing response of the nanocomposite was examined. It was found that the conductivity varied according to low humidity to high humidity. The composite showed good humidity response, ion-exchange capacity and electrical conductivity. Poly-o-toludine–TiP nanocomposite was also used to study electrical conductivity under isothermal conditions in the temperature range 50–130°C. The composite was found stable under ambient conditions below 90°C in terms of DC electrical conductivity retention. These studies suggest that the cation exchange nanocomposite could be a good sensing material for humidity. [Copyright &y& Elsevier]

Abstract: In this study, the electrically conducting polyaniline–titanium(IV)phosphate (PANI–TiP) cation exchange nanocomposite was synthesized by sol–gel method. The cation exchange nanocomposite based sensor for detection of ammonia vapors was developed at room temperature. It was revealed that the sensor showed good reversible response towards ammonia vapors ranging from 3 to 6%. It was found that the sensor with p-toluene sulphonic acid (p-TSA) doped exhibited higher sensing response than hydrochloric acid doped. This sensor has detection limit ≤1% ammonia. The response of resistivity changes of the cation exchange nanocomposite on exposure to different concentrations of ammonia vapors shows its utility as a sensing material. These studies suggest that the cation exchange nanocomposite could be a good material for ammonia sensor at room temperature. [Copyright &y& Elsevier]

Abstract: A nano-composite inomeric poly-o-anisidine Sn(IV) phosphate [POASn(IV)P] was prepared via sol–gel mixing of an electrically conducting organic polymer, poly-o-anisidine with the matrices of inorganic precipitate of Sn(IV) phosphate. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV–vis spectrophotometry, FTIR, TGA–DTA, TEM, XRD and SEM studies. Electrical conductivity studies were carried out by four in-line probe DC electrical conductivity measuring instrument. The conductivity was found within the range of semiconductor region (10−3 to 10−2 S/cm). Isothermal and cyclic techniques were also used to understand the stability in terms of DC electrical conductivity retention. [Copyright &y& Elsevier]

Composite materials formed by the combination of inorganic ion exchangers of multivalent metal acid salts and organic conducting polymers (polyaniline, polypyrrole, polythiophene, etc.), providing a new class of ‘organic–inorganic’ hybrid ion exchangers with better mechanical and granulometric properties, good ion-exchange capacity, higher stability, reproducibility and selectivity for heavy metals. Such a type of ion exchanger ‘polyaniline Sn(IV) tungstoarsenate’ was developed by mixing polyaniline into inorganic precipitate of Sn(IV) tungstoarsenate. This material was characterized using atomic absorption spectrometry, elemental analysis, Fourier transform infrared spectroscopy, simultaneous thermogravimetry–differential thermogravimetry, X-ray and scanning electron microscopy studies. Ion-exchange capacity, pH-titrations, elution and distribution behavior were also carried out to characterize the material. On the basis of distribution studies, the material was found to be highly selective for Cd(II) and its selectivity was tested by achieving some important binary separations like Cd(II)–Zn(II), Cd(II)–Pb(II), Cd(II)–Hg(II), Cd(II)–Cu(II), etc., on its column. Using this composite cation exchanger as electroactive material, a new heterogeneous precipitate based selective ion-sensitive membrane electrode was developed for the determination of Cd(II) ions in solutions. The membrane electrode is mechanically stable, with a quick response time, and can be operated within a wide pH range. The selectivity coefficients for different cations determined by mixed solution method were found to be less than unity. The electrode was also found to be satisfactory in electrometric titrations. [Copyright &y& Elsevier]