Monalisha Boruah

Biocompatible carboxymethylcellulose-g-poly(acrylic acid)/OMMT nanocomposite hydrogel for in vitro release of vitamin B12

The present work describes the preparation of a biocompatible nanocomposite hydrogel based on CMC-g-PAA and organo-MMT nanoclay by using methylene bis-acrylamide (MBA) as a cross-linker and potassium persulfate (KPS) as an initiator through radical graft polymerization. The nanocomposite hydrogels were characterized by using techniques such as FTIR, SEM and XRD analysis. The effects of various parameters on the swelling behaviour of the hydrogels were studied. The mechanical strength of the nanocomposite hydrogels was determined by dynamic mechanical analysis (DMA) and all the samples showed an increase in the storage modulus (G′) with an increase in cross-linker amount. The in vitro biocompatibility of the nanocomposite hydrogels showed that the presence of nanoclay in the nanocomposite hydrogel enhanced the in vitro blood compatibility. The vitamin B12 release mechanism has been studied during different time periods using a UV-visible spectrophotometer. The drug release kinetics revealed that release of vitamin B12 follows a non-Fickian diffusion mechanism.

Study of Optical and Photovoltaic Properties of N-Alkyl Substituted Polycarbazole Derivative and Its Copolymer with Thiophene

Poly(9-dodecylcarbazole) (PDDC) and poly[(9-dodecylcarbazole)-co-thiophene] (PDDCT) were studied for optical and electrochemical properties and found the polymers as promising material to be used for the solar cell. The electrochemical band gap for the polymers PDDC and PDDCT were calculated to be 2.21 eV and 1.91 eV, respectively. The absorption spectra showed broad absorption over the wavelength range of 350–590 nm with maximum absorptions at 414 and 443 nm (λmax), respectively, for PDDC and PDDCT. The polymeric photovoltaic cells based on blend of polymer and TiO2 nanoparticles were fabricated and the power conversion efficiency (PCE) of the photovoltaic cells were measured to be 0.11% and 0.14%, respectively, for PDDC and PDDCT, and improved the same up to 0.18% and 0.24% upon annealing of the active layer films at 150°C for 30 minutes.

Development of Dye-Sensitized Solar Cells Based on Gold/Gelatin Gel Electrolyte: Effect of Different Aspect Ratio of Gold Nanocrystals

This study describes the application of gold/gelatin (Au/gelatin) gel electrolyte to a set of quasi-solid-state dye-sensitized solar cells (DSSCs). A set of DSSC based on Au/gelatin gel electrolyte was developed. Au nanocrystals of different aspect ratio were synthesized and immobilized in gelatin gel electrolyte. The structures of the synthesized nanocrystals and nanocomposite gel were confirmed by using Fourier transform infrared spectroscopy, a scanning electron microscopy energy-dispersive X-ray, and transmission electron microscopy analysis. The thermogravimetric analysis indicated that introduction of Au nanocrystals to the polymer matrix resulted in an increase in thermal stability. Fabricated DSSC was exposed to a 100-mW/cm2 solar simulator in ambient atmosphere. It was observed that the photoconversion efficiency (PCE) changes with different aspect ratio of Au. In addition, significantly high open-circuit voltage (Voc), current density (Jsc), and PCE of 0.656 V, 4.94 mA · cm-2, and 1.975%, respectively, are found for Au nanocrystals with maximum aspect ratio of 3.5 at an optimum concentration of 0.04%.