Kowsar Majid

Synthesis, characterization, and thermal study of polyaniline composite with the photoadduct of potassium hexacyanoferrate (II) involving hexamine ligand

The present paper involves the synthesis of polyaniline (PANI) composite with photoadduct of potassium hexacyanoferrate (II) involving hexamine as a ligand and cobalt chloride as a complexing agent via in situ oxidative polymerization by ammonium persulphate. The photoadduct has been synthesized by photoirradiation followed by substitution with the hexamine ligand. The final product has been isolated by using CoCl2 as complexing agent. Viscosity average molar mass has been determined by viscosity method using Ostwald’s viscometer. The photoirradiation, substitution, and successful synthesis have been proved by recording pH, UV–visible spectra before and after irradiation, and FTIR of the photoadduct. The composite based on the synthesized photoadduct has been subjected to FTIR, X-ray diffraction, and SEM characterization techniques. Thermal analysis has been done by using TG and DSC technique. FTIR absorption peaks confirm the insertion of photoadduct in the backbone of PANI. SEM of the composite also supports its successful synthesis. The XRD of photoadduct shows crystalline structure, which has remained dominant in the composite, hence proving the successful synthesis of PANI composite with photoadduct. Thermal analysis shows high thermal stability of photoadduct which in turn has improved the thermal stability of PANI composite, therefore, shows the potential of composite for high-temperature application purposes.

Enhanced photocatalytic activity exhibited by PTh/[Fe(CN)3(NO)(bpy)]·4H2O nanocomposite fibers via a synergistic approach

Successful synthesis of a photoadduct, [Fe(CN)3(NO)(bpy)]·4H2O and its use as a filler in polythiophene (PTh) matrix for synthesizing PTh/[Fe(CN)3(NO)(bpy)]·4H2O nanocomposite fibers by chemical polymerization. [Fe(CN)3(NO)(bpy)]·4H2O exhibited wide transparency in the entire visible region, thereby showing non-linear optical behavior (NLO) which has been confirmed by a second harmonic generation (SHG) test. The fibrous structure of the nanocomposite has been confirmed from TEM. Thermal analysis revealed increased thermal stability of the nanocomposite fibers than pure PTh. A dielectric study showed the capacitive effect of the nanocomposite fibers at low frequencies and a conductivity effect at high frequencies. This behavior may provide an absorptive and reflective mechanism to EMI shielding. Meanwhile, a higher photocatalytic activity of the present material for methyl orange (MO) dye has been observed than for many other two component systems as reported in the literature. This has been attributed to the presence of a synergistic effect between PTh and photoadduct particles which is believed to play an essential role in affecting the photoreactivity. From BET, the surface area of the nanocomposite has been found to be 18.9 m2 g−1. The main contributing factor to the enhanced photocatalytic activity of the nanocomposite fibers has been attributed to the interface contact between PTh and photoadduct particles, as is evidenced by PL measurements. Also, the degradation mechanism of the photocatalytic process has been proposed and the active species involved to cause degradation are confirmed by using different scavengers. Kinetic study revealed the degradation process to follow second order kinetics with an observed rate constant of 7 × 10−4 L mol−1 s−1.

Role of photoadduct of K4Fe(CN)6 and C3H4N2 in improving thermal stability of polyaniline composite

This paper involves the synthesis of polyaniline composite with photoadduct of potassium hexacyanoferrate and imidazole via photochemical route by oxidative polymerization technique by ammonium persulphate. The photoadduct has been synthesized by photoirradiation followed by substitution with imidazole ligand. The photoaquation, substitution and successful synthesis has been proved by recording pH, UV visible spectra before and after irradiation and XRD of photoadduct. The as synthesized composite has been subjected to various characterizations like elemental analysis, UV–Visible spectra, FTIR, XRD, SEM, and TG/DTG. XRD of photoadduct shows crystalline structure which has been retained in the composite, changing the amorphous structure of polyaniline into the crystalline one, hence proving the insertion of photoadduct in the polymer chain. Various parameters like crystallite size (L), interplanar distance (d), micro strain (ε), dislocation density (δ) and distortion parameters (g) were calculated from XRD data. Thermal analysis shows the high thermal stability of composite which can be due to strong interaction between polymer chain and the photoadduct which restricts the thermal motion of polyaniline and thus enhances the thermal stability of composite.

Synthesis, characterization, photophysical, thermal and electrical properties of composite of polyaniline with zinc bis(8-hydroxyquinolate): a potent composite for electronic and optoelectronic use

A composite of polyaniline (PANI) with the metal complex zinc bis(8-hydroxyquinolate) [Zn(8HQ)2] is synthesized by an in situ polymerization technique. The metal complex and the synthesized PANI–[Zn(8HQ)2] composite are characterized by EDX, FTIR, XRD and TG analysis. FESEM analysis shows distinct morphological features of PANI and the PANI–[Zn(8HQ)2] composite. XRD shows the crystalline nature of the metal complex, which is retained in the PANI–[Zn(8HQ)2] composite. TG reveals the higher thermal stability of the PANI–[Zn(8HQ)2] composite as compared to pure PANI. DSC shows an increase in the glass transition temperature of the PANI–[Zn(8HQ)2] composite, which indicates its rigid nature. UV-visible spectral characterization confirms the red shift of polyaniline upon doping with the zinc complex. The metal complex exhibits excellent photophysical properties, good thermal stability and conducting behavior. The fluorescence intensity of the PANI–[Zn(8HQ)2] composite is found to be much higher than that of pure PANI. The relative fluorescence quantum yield of the PANI–[Zn(8HQ)2] composite is a few orders of magnitude higher than that of pure PANI. The conductivity of the PANI–[Zn(8HQ)2] composite is greater than that of the pure PANI, as detected by a four probe method, and IV characteristics suggest semiconducting and conducting behavior of the pure PANI and PANI–[Zn(8HQ)2] composite, respectively. The aforementioned results suggest that the synthesized polymer composite is a potent material for electronic and optoelectronic applications such as light emitting diodes, solar cells and other semiconductor devices.

Synthesis, characterization, thermal and electrical properties of composite of polyaniline with cobaltmonoethanolamine complex

The present paper involves the synthesis of polyaniline (PANI) composite with cobaltmonoethanolamine [Co(mea)2(H2O)2Cl2] complex via in situ oxidative polymerization by ammonium persulphate. The complex has been synthesized by refluxing method. The composite has been subjected to UV-Visible spectra, FT-IR, X-ray diffraction, SEM and electrical conductivity characterization techniques. Thermal analysis has been done by using TG and DSC techniques. FT-IR absorption peaks confirm the insertion of complex in the backbone of PANI. SEM of the composite also supports its successful synthesis. The XRD of composite also shows crystalline structure hence, proving the successful synthesis of PANI. Thermal analysis shows enhanced thermal stability of polyaniline. In the present composite system, the polymerization of PANI with [Co(mea)2(H2O)2Cl2] complex causes strong interfacial interactions between PANI and [Co(mea)2(H2O)2Cl2] complex crystallites, also suggested by the FT-IR and XRD studies, thereby changing the molecular conformation of PANI from compact coil structure to an expanded coil-like structure. As a consequence, there is an enhancement in the conductivity of composite of PANI up to certain dopant concentration. The anticorrosive property of a coating of PANI/[Co(mea)2(H2O)2Cl2] composite on mild steel coupon in 3 M HNO3 was evaluated using weight loss measurement and compared with pure polyaniline coating. The said composite has shown anticorrosive property and can thus, act as a potent dopant for enhancing corrosion resistance of PANI coatings.

In-situ synthesis of visible-light responsive Ag 2 O/graphene oxide nanocomposites and effect of graphene oxide content on its photocatalytic activity

AbstractAg2O/graphene oxide nanocomposites, as efficient photocatalysts, were prepared by an in situ method using AgNO3 and graphene oxide as reactants under controlled atmosphere. Graphene oxide is synthesised via an eco-friendly method, and the Ag2O nanoparticles displaying elongated spherical morphology are randomly distributed on the surface of GO. The as-synthesised nanocomposites were characterised by different characterisation techniques. The results proved that the concentration of graphene oxide in starting solution displayed an important role in photocatalytic performance of Ag2O/graphene oxide nanocomposites. The nanocomposite materials were found to exhibit very improved photocatalytic activity for degrading methylene blue (MB) and Rhodamine B (Rh-B) under visible light irradiation. The photocatalytic activities of the composite were higher than that of P25 (a commercial TiO2 as a benchmark photocatalyst). The significantly improved photocatalytic activity of the nanocomposites could be attributed to the high charge separation and suppressed recombination of photogenerated electron-hole pairs due to GO. The effects of reaction parameters such as pH and the effect of different scavengers on the photocatalytic activity of the composite were studied. Graphical abstractThis reflects high charge separation of photogenerated charge carriers through graphene oxide and thus increased photocatalytic activity by Ag2O/GO composites.

Synthesis, Characterization and Study of Effect of Irradiation on Electronic Properties of Polyaniline Composite with Metal Complex of Co (III)

The present work reports the synthesis of PANI composite with hexamminecobalt(III) chloride metal complex as dopant via in situ oxidative polymerization by ammonium persulphate in non-aqueous DMSO medium. The dopant metal complex has been synthesized by known method and characterized by using FTIR, XRD and SEM analysis. The synthesized PANI/[Co(NH3)6] Cl3 composite was characterized by FTIR, XRD, UV-Vis and SEM techniques. FTIR of PANI composite showed its successful synthesis with the presence of some dopant peaks in its FTIR spectrum. XRD spectra of composite revealed its crystalline nature having almost same spectra as that of dopant metal complex with slight shift in the position of peaks. Electrical measurement of the composite was made using four probe conductivity meter and the thermal studies have been done by thermal gravimetric (TG) technique. The results showed improvement in the thermal stability of PANI composite together with increase in its conductance, thereby making it a possible future material for high temperature application purposes. Electronic properties of the composite were investigated using UV-Vis spectroscopy which revealed decrease in the energy band gap of the composite on irradiation. This is attributed to the distortion of polymer chains on exposure to radiations, which results in decrease in conjugation and hence increases in band gap energy.

Synthesis, characterisation and electric properties of polythiophene composites with various amphoteric oxides

Abstract The present paper involves the synthesis of polythiophene (PTP) composites with different amphoteric oxides via in situ oxidative polymerisation procedure. These composites were characterised by Fourier transform infrared, X-ray diffraction and SEM, which proves the successful chemical synthesis of PTP and its composites. Fourier transform infrared absorption peaks confirm the insertion of oxides in the backbone of PTP. Thermal analysis shows no change in thermal stability, unlike composites of PTP with other metal oxides, and hence rules out the application of these composites for higher temperature purposes. However, the composite materials have shown stability up to 200°C which ensures their use in low temperature applications. Both the oxides have changed the electrical conductivity of PTP. Polythiophene prepared which was found to be insulator initially has shown significant conductivity after doping with two amphoteric oxides. Sb2O3 has proven to be a better dopant for improving the conductivity as compared to TeO2.

Investigation of the transport properties of PPy/[Co(EDTA)NH3Cl]·H2O nanocomposite prepared by chemical oxidation method

Charge transport across a potential barrier is important in determining the properties of many devices ranging from solar cells to the production of H2. This paper reports the synthesis of photoadduct: [Co(EDTA)NH3Cl]·H2O via a photochemical route and its use as filler in polypyrrole (PPy) matrix for the formation of a semiconductor–insulator–semiconductor (SIS) nanocomposite junction by in situ chemical polymerization. Particle size of photoadduct obtained from XRD and TEM has been well correlated. TEM clearly showed a two phase system consisting of PPy flakes in between which are the photoadduct particles. This leads to the formation of an SIS junction. Thermal analysis of the nanocomposite junction revealed its higher thermal stability than pristine PPy. The dielectric constant and dielectric loss exhibit normal dispersion behavior with frequency. A decreasing trend of dielectric loss is dominated by the dc-conduction losses which is confirmed by the electric modulus formalism. From the fitted Cole–Cole impedance plot, resistance of the nanocomposite has been found to be 8 × 103 Ω. Different models have been used to account for the non-linear I–V curves of the synthesized SIS junction. The extended fluctuation induced tunneling (FIT) conduction model fits best, confirming the formation of an SIS junction wherein PPy flakes acts as semiconductor and the photoadduct as an insulating barrier. The shape of the insulating barrier changes upon increasing bias voltage, thereby favoring quantum mechanical tunneling. This is useful for photo-detector applications.

Studying the electrical, thermal, and photocatalytic activity of nanocomposite of polypyrrole with the photoadduct of K3[Fe(CN)6] and diethylenetriamine

The present work reports the synthesis of nanocomposite of polypyrrole with [Fe(CN)3(dien)].H2O photoadduct via in-situ oxidative chemical polymerisation. Photoadduct was synthesised by irradiating an equimolar mixture of K3[Fe(CN)6] and diethylenetriamine (dien) using Osram photo lamp. The successful synthesis of photoadduct was proved by Elemental analysis, UV-Vis and FTIR spectra. Nanocomposite of photoadduct with PPY was then prepared by oxidative chemical polymerization using FeCl3 as oxidant. The successful synthesis of the nanocomposite was confirmed from FTIR, XRD and SEM. The nanocomposite showed significant increase in thermal stability, dielectric constant and ac-conductivity as compared to pure polypyrrole. The photocatalytic activity of the materials was also studied against the methyl orange (MO) dye under UV-Vis light and nanocomposite showed efficient photocatalytic activity (91 % degradation after 2 hrs) than pure PPY which showed only 24% degradation of dye after 2 hrs. Thus as synthesised nanocomposite can be effectively utilised for the removal of organic dyes.