Enhancement in crystallinity of poly(3-hexylthiophene) thin films prepared by low-temperature drop casting

Low-temperature casting of high molecular weight (HMW > 40 kDa) regioregular poly(3-hexylthiophene) (P3HT) is demonstrated to yield highly crystalline P3HT thin films with well defined and preferentially edge-on oriented [(100) contact plane] nanocrystallites on the pure and silanized Si/SiO₂ substrates. Transmission electron microscopy and X-ray diffraction provide evidence for the increase in preferential edge-on orientation of P3HT-conjugated backbone while decreasing the film preparation temperature below room temperature. The optimum growth temperature is about −12°C for the given concentration (2 mg/mL in CHCl₃). The reduced evaporation rate of the solvent results in a better selection of the thermodynamically stable orientation of nanocrystallites onto the substrate. The degree of preferential orientation and size of the crystallites can be further increased on n-octadecyltrichlorosilane-treated SiO₂ substrates as well as by annealing the films at 200°C for 1 h. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hypoglycaemic and Hypolipidaemic Effects of Withania somnifera Root and Leaf Extracts on Alloxan-Induced Diabetic Rats

Withania somnifera is an important medicinal plant, which is used in traditional medicine to cure many diseases. Flavonoids were determined in the extracts of W. somnifera root (WSREt) and leaf (WSLEt). The amounts of total flavonoids found in WSREt and WSLEt were 530 and 520 mg/100 g dry weight (DW), respectively. Hypoglycaemic and hypolipidaemic effects of WSREt and WSLEt were also investigated in alloxan-induced diabetic rats. WSREt and WSLEt and the standard drug glibenclamide were orally administered daily to diabetic rats for eight weeks. After the treatment period, urine sugar, blood glucose, haemoglobin (Hb), glycosylated haemoglobin (HbA1C), liver glycogen, serum and tissues lipids, serum and tissues proteins, liver glucose-6-phosphatase (G6P) and serum enzymes like aspartate transaminase (AST), alanine transaminase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) levels were determined. The levels of urine sugar, blood glucose, HbA1C, G6P, AST, ALT, ACP, ALP, serum lipids except high density lipoprotein-bound cholesterol (HDL-c) and tissues like liver, kidney and heart lipids were significantly (p < 0.05) increased, however Hb, total protein, albumin, albumin:globulin (A:G) ratio, tissues protein and glycogen were significantly (p < 0.05) decreased in alloxan-induced diabetic rats. Treatment of the diabetic rats with WSREt, WSLEt and glibenclamide restored the changes of the above parameters to their normal level after eight weeks of treatment, indicating that WSREt and WSLEt possess hypoglycaemic and hypolipidaemic activities in alloxan-induced diabetes mellitus (DM) rats.     

Structurally modified poly(methyl methacrylate) electrospun nanofibers as better host matrix for noble metal nanoparticles

Poly(methyl methacrylate) (PMMA) nanofibers are proved as good host matrix for various nanomaterials. Here, the possibilities offered by the process of electrospinning are exploited for the production of pure and structurally modified surface roughened and coaxial hollow PMMA electrospun nanofibers with unique advantages and surface characteristics, which is proved through various structural analyses. The host matrix nature of these pure and structurally modified surface roughened and coaxial hollow PMMA nanofibers to gold nanoparticles (AuNPs) are proved through different structural and morphological analyses. The host matrix nature of pure and structurally modified surface roughened and coaxial hollow PMMA nanofibers to AuNPs are compared with that of pure PMMA nanofibers by comparing their structural and optical properties. It is found here that, the surface roughened PMMA nanofibers act as better host matrix with more uniform distribution of particles and intensity enhancement than the pure and coaxial hollow PMMA nanofibers. Pure and coaxial hollow PMMA nanofibers show almost two times enhancement in intensity while the surface roughened PMMA nanofibers show almost five times enhancement in intensity after incorporating AuNPs. The host matrix nature of PMMA nanofibers is thus proved to be improved by making structural modifications on PMMA nanofibers in a simple and cost-effective way. This makes them more suitable and adaptable in their applications. This superior property of surface roughened PMMA nanofibers over pure PMMA nanofibers can be used in all the application fields of PMMA nanofibers like optical works, catalytically supporting agents, antibacterial supporting systems and so on.     

Electrochemical machining process parameter optimization using particle swarm optimization

Electrochemical machining (ECM) is a nontraditional process used for the machining of hard materials and metal‐matrix composites. Composites are used in several applications such as aerospace, automobile industries, and medical field. The determination of optimal process parameters is difficult in the ECM process for obtaining maximum material removal rate (MRR) and good surface roughness (SR). In this paper, a multiple regression model is used to obtain the relationship between process parameters and output parameters. Particle swarm optimization (PSO) is one of the optimization techniques for solving the multiobjective problem; it is proposed to optimize the ECM process parameters. Current (C), voltage (V), electrolyte concentration (E), and feed rate (F) are considered as process parameters, and MRR and SR are the output parameters used in the proposed work. The developed multiple regression is statistically analyzed by regression plot and analysis of variance. The optimized value of MRR and SR obtained in PSO is 0.0116 g/min and 2.0106 μm, respectively. Furthermore, PSO is compared with the genetic algorithm. The PSO technique outperforms the genetic algorithm in computation time and statistical analysis. The obtained values are validated to test the significance of the model, and it is noticed that the error value for MRR and SR is within 0.15%.