Ufana Riaz

Effect of Dopant on the Nanostructured Morphology of Poly (1-naphthylamine) Synthesized by Template Free Method

The study reports some preliminary investigations on the template free synthesis of ascantly investigated polyaniline (PANI) derivative—poly (1-naphthylamine) (PNA) by template free method in presence as well as absence of hydrochloric acid (HCl) (dopant), using ferric chloride as oxidant. The polymerization was carried out in alcoholic medium. Polymerization of 1-naphthylamine (NPA) was confirmed by the FT-IR as well as UV–visible studies. The morphology and size of PNA particles was strongly influenced by the presence and absence of acid which was confirmed by transmission electron microscopy (TEM) studies.

Evaluation of Antibacterial Activity of Nanostructured Copolymers of Poly (Naphthylamine)

The present preliminary investigation highlights for the first time the antibacterial activity of copolymers of nanostructured poly (naphthylamine) (PNA) with aniline (PNA-co-PANI) and o-toluidine (PNA-co-POT) against E. coli and S. aureus. The antibacterial effect of these nanosized polymers was found to be much higher than that reported for pristine polyaniline. The chemical structure and morphology of the copolymers was found to play a significant role in deciding the antimicrobial efficiency of the copolymers. A proposed mechanism of antimicrobial effect has also been suggested. Our results indicate that the antimicrobial effects of the copolymers could be useful ingredients for biomaterials used in the development of food packaging and medical devices.

Compatibility Studies on Dehydrated Castor Oil Epoxy Blend with Poly(Methacrylic Acid)

Blending is a useful technique to improve upon the physico‐mechanical properties of the polymers. Synergies of the properties of the two polymers occur best when they are miscible or compatible with each other. Vegetable oil epoxy can be used for blending with polymers to improve upon their physical and mechanical properties. Poly(methacrylic acid) (PMAA) is a hard, brittle and water sensitive material. Dehydrated castor oil epoxy (DCOE), a product from a sustainable resource, has been chosen to improve upon the physical and mechanical properties of PMAA through solution blending. Blends of DCOE/PMAA were prepared in the weight ratios 80/20, 60/40 and 20/80 through a solution method by mixing in dimethyl sulphoxide. In the first instance, the miscibility of the two components was investigated using the techniques of viscosity and ultrasonic measurements. The study revealed that the two components showed semicompatibility/semimiscibility in solution. The compatibility in the solid phase was examined by differential scanning calorimetry and scanning electron microscopy which revealed that DCOE–PMAA pair were incompatible in solid phase.

Microwave-assisted green synthesis of some nanoconjugated copolymers: characterisation and fluorescence quenching studies with bovine serum albumin

Copolymerization is an effective technique to design conjugated polymers with properties higher than individual homopolymers, as the composition and the desired chemical properties can be controlled by the judicious choice of co-monomers and polymerization techniques. With a view to explore the influence of microwave-assisted copolymerization on the spectral and fluorescence properties of some functionalized monomers, the present work reports for the first time, the synthesis of conjugated copolymers of poly(1-naphthylamine), poly(o-phenylenediamine), and poly(o-anisidine) under microwave irradiation. Fourier transform infrared spectroscopy confirmed random copolymerization, while ultraviolet-visible studies revealed the variation in polaronic states upon copolymerization. High crystallinity was achieved through the formation of a distorted orthorhombic lattice and controlled morphology via microwave-assisted synthesis which was confirmed by X-ray diffraction and transmission electron microscopy analysis. This behaviour was explained on the basis of variable orientations adopted by the conducting polymer chains. A water soluble homopolymer and a copolymer were tested for the deactivation of bovine serum albumins fluorescence and the former was found to effectively quench the fluorescence emission of the latter. Quenching occurred through formation of an intermolecular complex and was initiated by photoinduced electron transfer and was observed to be static in nature. The quenching rate constant, kq, for POPD and POPD-co-PNA was found to be 1.08 × 1014 L M−1 s−1 and 2.0 × 1014 L M−1 s−1, revealing a much higher quenching rate constant kq for the copolymer than the homopolymer. Likewise, the binding constants, Ka, for a homopolymer and a copolymer were found to be 3.98 × 106 L mol−1 and 1.26 × 107 L mol−1, revealing a much higher binding constant for the copolymer POPD-co-PNA than the homopolymer POPD. Confocal microscopy revealed widely distributed binding of the copolymer with the tryptophan residues in the protein scaffold. These results reveal that the copolymer holds potential for use in bioimaging and also as a protein sensor.

Synergistic effect of microwave irradiation and conjugated polymeric catalyst in the facile degradation of dyes

Microwave-enhanced photodegradation of dyes is one of the emerging and promising technologies for waste water remediation. Microwaves effectively accelerate photocatalytic degradation, but only in the presence of a suitable photocatalyst such as TiO2, ZnO and also when a microwave electrodeless lamp (MEL) substitutes a traditional lamp as a light source. As the existing inorganic photocatalysts have been proven to be potentially toxic to the aquatic environment, this remediation technique can be extremely simplified if the photocatalyst can be replaced by a benign catalyst which can work under microwave irradiation in the absence of any external light source. In the present study, an attempt is made for the first time to degrade and mineralize Orange G (OG) dye in a laboratory microwave oven at 30 °C, using an organic catalyst, poly(1-naphthylamine) (PNA), a conjugated polymer synthesized by an enzymatic method. PNA was characterized by relevant experimental techniques. The degradation was carried out by exposing the OG dye solutions to microwave irradiation for different time intervals in the absence of UV-vis radiation and TiO2. PNA as a catalyst was found to enhance the dye degradation under microwave irradiation by almost two times as compared to its degradation under microwave irradiation alone. 100 ppm of OG dye solution was found to degrade up to 90% in 20 min at 30 °C in the presence of PNA. The same solution revealed mineralization up to 85% in 40 min as confirmed by the total organic content (TOC) analysis. With the help of LC-MS, seven intermediates were identified ranging between m/z 227 and m/z 97, on the basis of which a tentative degradation pathway for the dye has been proposed. Dye degradation in the presence of PNA as a microwave catalyst under the present experimental setup was found to yield results better than other photocatalytic or microwave-assisted photocatalytic degradation methods.

Role of Conducting Polymers in Enhancing TiO2-based Photocatalytic Dye Degradation: A Short Review

Research in the field of TiO2-based photocatalysis has gained wide attention to address important energy and environmental problem. Lately, the use of conducting polymers as photosensitizers has proven to immensely enhance photodegradation by exhibiting excellent photocatalytic activity under both ultraviolet light and natural sunlight irradiation which is not possible using semiconductors alone. Considering the unique performance of conducting polymer-based nanocomposites in photocatalysis, the present review provides the recent advances in the development of ultraviolet and visible light-responsive conducting polymer-based TiO2 nanocomposites for their potential application in environmental remediation. This review ends with a summary focusing on the challenges and new dimensions in this still emerging area of research. GRAPHICAL ABSTRACT

Effect of microwave irradiation time and temperature on the spectroscopic and morphological properties of nanostructured poly(carbazole) synthesized within bentonite clay galleries

Microwave irradiation has been widely used in the synthesis of organic, inorganic, and inorganic–organic hybrid materials because of its well known advantages over conventional synthetic routes. Polycarbazole (PCz) is a hole transporting conducting polymer and by virtue of this property is attracting considerable attention for its application in organic light emitting diodes (OLEDs) and solar cells. For advanced technologies, PCz of controlled morphology, nano dimension, and higher optoelectronic properties is desired. These objectives are achievable through using innovative synthetic routes. Towards this end, we have attempted to synthesize PCz under solid state conditions in the confined environment of the interlayer space of bentonite clay through microwave irradiation with ammonium persulphate as initiator. The effect of time and temperature of microwave irradiation on the shape, size, molar mass, UV-vis and fluorescence characteristics of PCz and PCz–clay nanohybrids have been thoroughly investigated and interpreted. The temperature of the microwave irradiation was from 30 to 50 °C and the time was varied from 2 to 6 min. The effects of both temperature and time of microwave irradiation on the synthesized nanocomposite was investigated by FT-IR, UV, XRD techniques. PCz extracted from clay galleries exhibited a spherical shape under all synthesis conditions. The size of spheres, in the nanosize domain, was found to be dependent upon the temperature and time of microwave irradiation. UV-vis spectral analysis showed that microwave irradiation produced a polaronic state in PCz like cyclic voltammetry (CV). Oscillator strength of the polaronic transition was noticeably enhanced with temperature and time of microwave irradiation. FT-IR analysis revealed that PCz formed spiral shaped particles within clay galleries. Time and temperature of microwave irradiation was found to significantly enhance the fluorescence intensity of PCz–bentonite nanocomposites; thus the HOMO and LUMO orbitals of PCz are favorably perturbed by microwave irradiation in a significant measure. Enhancement of optoelectronic parameters of microwave synthesized PCz is expected to drastically improve the quantum efficiency of OLEDs and power efficiency of organic solar cells.

Plant Oil Renewable-Resource-based Biodegradable Blends as Green Alternatives in Biopackaging

This preliminary work reports the development of biodegradable films using blends of dehydrated castor oil epoxy (DCOE) with poly (methylmethacrylate) (PMMA) and poly(methacrylic acid) (PMAA). The biodegradability characteristics of the blends were investigated using degradation in phosphate buffer, activated sludge, and soil burial test measurements. The results revealed that the blends with higher content of DCOE underwent higher degradation as compared to the blends with lower DCOE content. Among the DCOE/PMMA and DCOE/PMAA blends, the latter were found to exhibit higher degradation, which was explained with the help of a suitable mechanism.

Conducting Semi‐interpenetrating Polymer Network of Polypyrrole with Poly(esteramide urethane) Synthesized from a Sustainable Resource

Semi‐interpenetrating polymer networks of polypyrrole with poly(esteramide urethane) (CPEAU) synthesized from a sustainable resource, (coconut oil) is being reported for the first time. The semi‐IPNs were prepared via chemical polymerization by immersing FeCl3 impregnated CPEAU films in a aqueous pyrrole solution for different time periods. CPEAU‐Py semi‐IPN films were found to be flexible, stiff, and having satisfactory conductivity when they were prepared by soaking in FeCl3 up to 4 h. Soaking for higher periods led to the deformation of films. Soaking for less than 2 h in FeCl3 resulted into poor polymerization of polypyrrole producing films of poor conductivity. Water uptake resulted in swelling of the films of pure CPEAU and was found to be maximum up to 10 wt%. Water uptake in the FeCl3 impregnated CPEAU films decreased with the increase in the impregnation time and fell up to 5 wt% of FeCl3 impregnated films. Conductivity of the semi‐IPN films was found to be in the semi‐conducting range 2.9 × 10−4 S cm−1−6.8 × 10−6 S cm−1 which happened to be higher than the conductivity values of the reported composites of poly(urethane)/polypyrrole. The semi‐IPN formation was further investigated by FT‐IR, thermal, and SEM analysis.

Comparative study of polyaniline and poly(1‐naphthylamine) dispersed oil polyurethane coatings

Purpose – The purpose of this paper is to report a comparative study of conducting polymer (CP) dispersed oil polyurethane coatings derived from a sustainable resource, i.e. polyaniline (PANI)/coconut oil polyesteramide urethane (CPEAU) and poly(1‐naphthylamine) (PNA)/linseed oil polyurethane (LPUA) coatings.Design/methodology/approach – The coatings were prepared chemically and were characterized for their physico‐chemical, physico‐mechanical, corrosion protective efficiency, and open circuit potential measurements. The morphological analysis of the corroded carbon steel (CS), coated uncorroded CS, and coated corroded CS specimens, was carried out by SEM analysis.Findings – The study revealed that the presence of a CP enhanced the corrosion protective efficiency of the sustainable resource‐based organic coatings. The type of CP used also played a major role in defining the corrosion resistance behavior of the coating materials.Originality/value – The comparative study of anticorrosive properties of CP wi...