Journal of Nano Structures
Volume:7 Issue: 2, Spring 2017

Among the several available techniques to produce the braided composite rods for construction industry, nidltrusion process is becoming the most widespread and cost-effective continuous processing technique. The work mentions the influence of carboxyl functionalized multiwalled carbon nanotubes (MWCNTs) on the maximum speed of manufacturing process. The epoxy polymer is diglycidyl ether of bisphenol F and the curing agent is an aromatic diamine. Appropriate temperature settings were determined using the optimization algorithm for two-dimensional heat transfer and curing model implemented to 8-mm diameter reinforcement with 0, 0.1, 0.2 and 0.3 wt% MWCNT. Final results allow concluding that only the use of 0.2 wt% MWCNT gives the highest nidltrusion speed. Other two batches (0.1 wt% and 0.3 wt% MWCNT) showed worse results compared to neat sample. The developed optimization algorithm can be further applied in the modeling of pultrusion process with using of different type of resin, curing agents and nanofillers.

La2O2SO4 nanoceramic was synthesized via sol-gel method using lanthanum nitrate and thioacetamid as precursors and stearic acid as polymeric precursor. The characterization studies were conducted by X-ray diffraction, energy dispersive X-ray spectroscopy and scanning electron microscopy. The result showed that the synthesized sample belongs to monoclinic structure with the average sizes between 70-80 nm. Further, the electrochemical behavior of La2O2SO4 nanoceramic was investigated by cyclic voltammetry using [Fe(CN)6]3-/4- redox couple. These results suggest that the La2O2SO4 nanoceramic is a highly promising candidate for electrochemical sensing of analytes.

The high crystallinity ZnO nanoparticles with an average particle diameter 30 nm have been successfully synthesized with a surfactant-mediated method. The cationic surfactant (cetyltrimethylammonium bromide, CTAB) and the hydrous metal chlorides (ZnCl2⋅2H2O) appear to be the good candidates for obtaining a high yield of nanoparticles. The structural and morphological characterizations were carried out by X-ray powder diffraction, scanning electron microscope and transmission electron microscopy, respectively. The resulting powders are highly crystalline and largely monodisperse ZnO nanoparticles. When used as a sensing material in gas sensor, it exhibits the high-performance gas sensing performances including high gas response, good selectivity, fast response/recovery time, good repeatability as well as stability towards low-ppm-level (10 to 100 ppm) n-butanol gas. At the optimal operating temperature (260 ºC), its gas response toward 100 ppm butanol is 174.8. The response and recovery time are 18 and 11 seconds, respectively. Theses findings not only provide a novel approach to fabricate ZnO nanoparticles via a surfactant-mediated method, but also explore a promising gas sensor towards n-butanol.

At the first stage Fe3O4 and Fe nanoparticles were synthesized via a simple hydrothermal method. Then silver nanoparticles and Fe-Ag nanocomposites were synthesized in the presence of NaBH4. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy, and Fourier transform infrared spectroscopy. Vibrating Sample magnetometer illustrated that Fe nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of Fe-Ag nanocomposites was investigated using the degradation of three various azo dyes under ultraviolet light irradiation. The results show that nanocomposites have feasible magnetic and photo catalytic properties.

TiO2 nanopowder is prepared by simple sol-gel method using starting material as titanium isopropoxide with methanol and annealed at 600°C, 700°C and 800°C for 1 hour in air. X-ray diffraction pattern revealed the presence of both anatase and rutile phase in TiO2 specimens annealed at different temperatures. It is observed that the content of rutile phase and crystallite size increases with increase in annealing temperature. Scanning electron microscopy (SEM) is used to study surface morphology of TiO2 specimens annealed at different temperatures. Using Tauc plot it is observed that energy band gap decreases with increase in annealing temperature. I-V curve of TiO2 specimen shows that current increases with increase in annealing temperature. The preparation method is optimized by changing the concentration of titanium isopropoxide which leads to mixed phase (anatase and rutile) TiO2 nanopowder with a lower energy band gap value which may play an important role in gas sensing applications.

In this research work, silica nano-porous thin films were deposited on glass substrates by layer by layer method. The thin films were calcinated at various calcination temperatures (200, 300, 400, and 500 °C). The morphology, surface characteristics, surface roughness and hydrophilic properties of the thin films were investigated by field emission scanning electron microscopy, attenuated total reflectance fourier transform infrared spectroscopy, atomic force microscopy and water contact angle analyzer. The surface characteristic showed that silica nano-porous thin film had an amorphous structure. The hydrophilic results indicated that the water contact angle of the glass coated silica nano-porous surface is decreased by increasing the calcinations temperatures to 300 °C and at higher temperature, it is increased. The deposition of silica nano-porous thin film on the glass surface at the optimum calcination temperature (300 °C) decreased water contact angle of the glass surface from 67° to 3°. Therefore, silica nanoporous thin film calcinated at 300 °C showed superhydrophilicity which greatly encourages the antifogging functions of the thin film.

There is a huge demand of silver nanoparticles in the global market due to their special properties and applications in different fields such as nanomedicine , dentists , nanocatalysis, nanoelectronics, textile field, waste water treatment.The major cons of top down and Bottom up methods are the synthesis processes are highly costly, time consuming and many harmful chemicals are used. To reduce these problems Green chemistry comes to play a very important role for making of silver nanoparticles. Use of various plant extracts like leaves, fruits for synthesis of biogenic silver nanoparticles referred as Green Nanotechnology. In the present work we reported the green synthesis of silver nanoparticles using by Mulberry leaves extract without using any toxic chemicals. The Mulberry leaves extract act as reducing agent as well as a stabilizing agent in green nanotechnology process. The making of silver nanoparticles was determined by the change of shade from white to brownish by the addition of Mulberry leaves extract . UV-Vis absorption spectroscopy was used to monitor the measurable formation of silver nanoparticles showed a maximum peak at 440 nm. High resolution Transmission electron microscope confirmed the spherical nature and the highly crystallinity of silver nanoparticles on an average size 15 -25 nm .Antimicrobial activity of the biogenic Ag nanoparticles was performed by a well diffusion method. The nanoparticles exhibited enhanced anti-bacterial activity when incubated in Escherichia Coli and Bacillus Subtilis cultured plates at varied volumes. Current study thus presents a facile and innovative strategy for synthesis of silver nanoparticles.

Chromium selenide (Cr2Se3) nanoparticles were prepared by hydrothermal method from Cr(NO3)3.9H2O and SeCl4 as precursors. These nanoparticles could be produced simply in the presence of cetyltrimethyl ammonium bromide, sodium dodecyl sulfate and polyethylenglycole 600 (PEG600) and 4ml of hydrazine hydrate (N2H4.H2O) at 180 ˚C for different times. By varying the reducing agent to potassium borohydride (KBH4), agglomerated structures with different morphologies were produced. The effects of surfactant, reducing agent, reaction time and temperature on the morphology of the products was investigated.

Nanostructured Al and Al-Mg (Mg 30 wt. %) powders with the mean crystallite sizes of 42 and 11 nm were prepared through the solid state ball milling technique. The milling process was performed for various times up to 12 h in argon atmosphere and the synthesized powders were in detail characterized by different techniques. The effect of milling time and Mg addition on the size, morphology, chemical composition, phase structure and crystallite size of the powder particles were thoroughly investigated and the results were compared with the non-alloyed Al system. Two distinct particle morphologies comprising lamellar flakes and solid granules were obtained as final milling products in Al and Al-Mg systems, respectively. It was revealed that Mg atoms gradually diffuse into the Al lattice during milling and form a supersaturated Al-Mg solid solution (α phase). Thermal analyses of the powders revealed that metastable nanostructures formed during the milling transform into the equilibrium and stable phases such as Al4C3 and Al2Mg3 (β) upon the heating.

A selective electrochemical method for the determination of uric acid was developed by using nano poly cresol red modified glassy carbon electrode. This new material has been characterized by Scanning Electron Microscopy, cyclic voltammetry and Differential pulse voltammetry. This modified electrode shows excellent electrocatalytic activity towards the oxidation of uric acid in the presence of ascorbic acid in (pH 7.0). Compare to bare electrode the modified electrode able to resolve the both ascorbic acid and uric acid in the solution mixture. The oxidation current of uric acid with the modified electrode is two folds higher that the bare glassy carbon electrode. Using differential pulse voltammetry method, the oxidation current is linear with the uric acid concentration in the range 30 µM - 575 µM with the detection limit of 5 µM (S/N = 3). Moreover uric acid in real samples can be determined using nano poly cresol red without any pretreatment of samples giving satisfactory results.