M. Francklin Philips

Development of a novel cyano group containing electrochemically deposited polymer film for ultrasensitive simultaneous detection of trace level cadmium and lead.

Poly(diphenylamine-co-2-aminobenzonitrile) (P(DPA-co-2ABN)), a cyano group containing conducting polyaniline derivative, has been electrodeposited developed as the new material and utilized for the simultaneous electrochemical determination of trace levels of cadmium (Cd(2+)) and lead (Pb(2+)). P(DPA-co-2ABN) film preconcentrates effectively through cyano chelation and electrochemically strips the heavy metal ions with well separated potentials, which are beneficially utilized for ppb level simultaneous detection of Cd(2+) and Pb(2+). Differential pulse voltammetry studies revealed that Cd(2+) and Pb(2+) ions were simultaneously stripped with well-defined, separated and sharp peaks for Cd(2+) and Pb(2+). The influence of various operational parameters such as pulse amplitude, pulse time, scan rate, initial potential, end potential, accumulation potential and accumulation time on the electrochemical stripping of heavy metals were investigated in details. Under the optimal conditions, good linear correlations were obtained from 1.26 to 907.8 ppm for Cd(2+) and 0.26 to 58.73 ppm for Pb(2+), respectively. Low detection limits for Cd(2+) and Pb(2+), 0.255 ppm and 0.165 ppm, respectively, were observed. The practical utility of the new procedure was demonstrated in real samples.

Course of poly(4-aminodiphenylamine)/Ag nanocomposite formation through UV-vis spectroscopy.

Kinetics of chemical oxidative polymerization of 4-aminodiphenylamine (4ADPA) was followed in aqueous 1 M p-toluene sulfonic acid (p-TSA) using silver nitrate (AgNO3) as an oxidant by UV-vis spectroscopy. The medium was found to be clear and homogeneous during the course of polymerization. The absorbances corresponding to the intermediate and the polymer were followed for different concentrations of 4ADPA and AgNO3 and at different reaction time. The appearance of a band around 450 nm during the initial stages of polymerization corresponds to the plasmon resonance formed by the reduction of Ag+ ions. Rate of poly(4-aminodiphenylamine)/Ag nanocomposite (RP4ADPA/AgNC) was determined for various reaction conditions. R(P4ADP/AgNC) showed second order power dependence on 4ADPA and first order dependence on AgNO3. The observed order dependences of 4ADPA and AgNO3 on the formation of P4ADPA/AgNC were used to deduce a rate equation for the reaction. Rate constant for the reaction was determined through different approaches. The good agreement between the rate constants obtained through different approaches justifies the selection of rate equation.

A kinetic study on the formation of poly(4 aminodiphenylamine)/copper nanocomposite using UV-visible spectroscopy.

The course of the reaction between copper sulfate (CuSO4) and 4-aminodiphenylamine (4ADPA) was monitored by UV-visible spectroscopy in p-toluene sulfonic acid (p-TSA). Formation of poly(4-aminodiphenylamine)/copper nanoparticle composite (P4ADPA/CuNC) was witnessed through the steady increase in absorbance at 410, 580 and >700 nm. The absorbance at 410 nm as well as >700 nm are correlated to the amount of P4ADPA/CuNC formation and was subsequently used to determine the rate of formation of P4ADPA/CuNC (RP4ADPA/CuNC) at any time during the course of the reaction. RP4ADPA/CuNC shows a first-order dependence on [4ADPA] and a half-order dependence on [CuSO4]. A kinetic rate expression was established between RP4ADPA/CuNC and experimental parameters such as [4ADPA] and [CuSO4]. The rate constant for the formation of P4ADPA/CuNC was 8.98 × 10(-3) mol(-0.5) l(0.5) s(-1). Field emission scanning electron and transmission electron micrographs revealed that the morphology of the P4ADPA/CuNC was influenced by the reaction conditions.

Preparation of poly(4-aminodiphenylamine)/silver nanoparticles composite and catalysis

Herein, we report the facile synthesis of a new nanocomposite, poly(4-aminodiphenylamine) (P4ADPA) supported silver nanoparticles (AgNPs) nanocomposite (NC) (P4ADPA/AgNC) in p-toluene sulfonic acid (p-TSA) medium. Field emission transmission electron microscopy reveals the existence of uniformly distributed AgNPs in the rod shaped P4ADPA matrix. P4ADPA/AgNC has been employed as the catalyst for the reduction of 4-nitrophenol (4NP) and the rate of reduction of 4NP was monitored by UV–Visible spectroscopy.

Deposition of Poly(diphenylamine-co-3-aminobenzonitrile)/Palladium Nanocomposite Film and Evaluation of Electrocatalytic Activity Toward Borohydride Oxidation.

New nanocomposites, poly(diphenylamine-co-3-aminobenzonitrile)/palladium (P(DPA-co-3ABN)/Pd) and poly(diphenylamine)/palladium (PDPA/Pd), have been prepared by pulse potentiostatic method and used as electrocatalysts for borohydride oxidation. Linear sweep voltammogram of P(DPA-co-3ABN)/Pd-ME exhibited the oxidation wave between -0.8 V and 0.4 V that corresponds to the direct, potentially four-electron, oxidation of borohydride ions. The peak current for borohydride oxidation is much higher at P(DPA-co-3ABN)/Pd-ME electrode as compared to PDPA/Pd-ME. The incorporation of 3ABN units augments electrocatalytic behavior and thermal stability for the P(DPA-co-3ABN)/Pd catalyst.