• KOWSAR MAJID

Articles written in Bulletin of Materials Science

• 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.

• Spectroscopic, morphological, thermal and dielectrical analysis of composite of polythiophene with photoactive transition metal complex of W(IV)

The present work involves the synthesis of polythiophene–potassium octacyanotungstate(IV) dihydrate compositevia in-situ oxidative chemical polymerization method using FeCl$_3$ as an oxidant. The resulting composite hasbeen subjected to Fourier transform infrared, X-ray diffraction (XRD) and scanning electron microscopy characterizationtechniques, which confirm the successful synthesis of the composite. XRD shows that the crystalline structure ofK$_4$[W(CN)$_8$] · 2H$_2$O has been retained in the composite. Thermogravimetric analysis data confirm the higher thermal stability of the composite in comparison with pure polythiophene, thus allowing it to be used as a promising material for high-temperature application purposes. Dielectric studies reveal that the dielectric constant and ac-conductivity of the compositeincreased by several orders of magnitude as compared with pure polythiophene at all frequencies, thus showing that thematerial can be used for various applications in the fields of charge storage devices and high-frequency device applications,and can also serve as a potential candidate for solar cell applications.

• Synthesis, characterization and optical absorption studies of Na[Fe(CN)$_4$(C$_3$H$_4$N$_2$)NO]2H$_2$O crystals

Crystals of Na[Fe(CN)$_4$(C$_3$H$_4$N$_2$)NO]2H$_2$O (SNP-d) have been prepared by photochemical route using sodium nitroprusside (SNP) as precursor complex. The crystals were subjected to various characterization techniques such as energy dispersive X-ray analysis, Fourier transform infrared, UV–visible spectroscopy and X-ray diffraction. From X-ray diffraction, it has been observed that SNP-d belongs to orthorhombic crystal system with primitive lattice. Crystallite size has been found to be 79.2 nm. Molecular structure of SNP-d depicts its non-centrosymmetric nature. As observed from UV–visible spectroscopy, SNP-d crystals form a double bandgap material, between which transitions have been found to be direct allowed. High value of refractive index and low value of reflectance, as obtained from Reddy, Anjaneyulu and Fresnel’s equations, indicate transparency of material to visible radiation. This is clearly justified from UV–visible spectra as the wavelength cutoff is around 300 nm.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020