Oxime-Modified Aluminum(III) Isopropoxide: A Promising Sol–Gel Precursor for Corrosion Resistive Nano-Alumina Coating on an Aluminum Alloy

Protection of Metals and Physical Chemistry of Surfaces - Dense alumina coatings were fabricated over aluminum alloy via dip coating method using oxime-modified aluminum(III) isopropoxide as a...     

Facile synthesis of rice shaped CuO nanostructures for battery application

The oxides of transition metals are an important class of semiconductors, which have applications in electronics, magnetic storage media, solar applications and catalysis. Among them, CuO has attracted much attention due to its widespread applications. In this paper, a facile synthesis of rice shaped CuO nanostructures have been prepared by reflux method for battery application using Copper nitrate and ammonia as precursors. Samples were prepared at three different reaction timings namely 6, 12 and 24 h. The as-prepared samples were calcinated at 400 °C to ensure the formation of copper oxide. The final products were subjected to X-ray diffraction, scanning electron microscopy, FT-IR and UV–Vis spectroscopy in order to study the effect of reaction time on the properties of the prepared copper oxide nanostructures. It is found that at controlled reaction time rice shaped CuO nanostructures are obtained. Cyclic voltammogram was recorded to understand the electrocatalytic behaviors of the rice shaped CuO sample prepared under optimized condition.     

Sol- gel synthesis of Ga2O3 nanorods and effect of precursor chemistry on their structural and morphological properties

Synthesis of mono-crystalline Ga₂O₃ Nanorods was done by sol-gel transformation of gallium(III) isopropoxide (Ga(OPrⁱ)₃). XRD studies were done to determine the planes and crystal structure of synthesized nanorods that showed the synthesis of β-Ga₂O₃(a). TEM studies of synthesized Ga₂O₃ confirmed the synthesis of monocrystalline β-Ga₂O₃ nanorods. To study the effect of precursor chemistry and to determine role of precursor structures on the crystal structure, phase and morphology of the Ga₂O₃, a new modified precursor complex was synthesized. The reaction of Ga(OPrⁱ)₃ with N-phenylsalicylaldimine, [C₆H₄(OH)CH=N(C₆H₅)] in 1:1?M ratio yielded [{(H₅C₆)N?=?CH-C₆H₄O}Ga(OPrⁱ)₂]. The newly synthesized complex was characterized by elemental analyses, molecular weight measurement, FT-IR and NMR (¹H and ¹³C) spectral studies. Spectral studies of the modified complex suggest the presence of bi-dentate mode of attachment of Schiff's base in the solution state. Sol-gel transformations of [{(H₅C₆)N?=?CH-C₆H₄O}Ga(OPrⁱ)₂] in organic medium, yielded γ-Ga₂O₃(b), as found by XRD studies. TEM image of the sample (a) revealed the formation of nano-rods of oxide with average diameter of ~100?nm whereas the TEM image of sample (b) showed presence of nano-sized particles of oxide with average particle size of 10?nm. Morphological and compositional studies of synthesized samples (a) and (b) were carried out using SEM and EDX. The method provides a possibility of large scale synthesis of dissimilar shaped and pure Ga₂O₃ nanoparticles.     

Synthesis and characterization of poly(ethylene oxide)‐based glycopolymers and their biocompatibility with osteoblast cells

Poly(ethylene oxide)‐block‐poly(methacryl‐d ‐glucopyranoside) (PEO‐GP) and poly(methacryl‐d ‐glucopyranoside) (H‐GP) glycopolymers were synthesized by deacetylation of acetylated polymers which were synthesized via atom transfer radical polymerization. The synthesized glycopolymers were characterized using ¹H NMR, ¹³C NMR and Fourier transform infrared (FTIR) spectroscopies, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The deacetylated polymers exhibited onset decomposition temperatures about 60 °C lower compared to the polymers having acetyl pendants. The glass transition temperature (T_g) of the acetylated homopolymer was 133 °C and that of the PEO‐based block copolymer was 124 °C. The deacetylated polymers H‐GP and PEO‐GP exhibited T_g values of about ?30 °C. Biocompatibility of the H‐GP and PEO‐GP glycopolymers was obtained by studying osteoblast cell adhesion, viability and proliferation in vitro. The cell viability showed an increase with increasing concentration of H‐GP from 0.1 to 1 µmol L^?1 and then decreased with further increase in its concentration (10–1000 µmol L^?1). PEO‐GP did not show a significant variation in cell viability on variation of its concentration from 0.1 to 1000 µmol L^?1. The significant improvement in biocompatibility with osteoblast cells in the presence of PEO‐GP was considered as due to the covalently bonded PEO segment of the methacrylate glycopolymer block. © 2014 Society of Chemical Industry     

Biological fluid interaction with controlled surface properties of organic micro-fluidic devices

An organic micro-fluidic device (O-MFD) on silicon/glass substrate was fabricated using plasma polymerisation of acrylic acid (ppAc) with optical lithography including wet and dry etching techniques. The surface chemistry of O-MFD was controlled by depositing ppAc films on MFD. The results showed that these surfaces have more than 50% retention of original monomer functionalities (-COOX) with significant concentration of CO and C-OX at the surface. The water fluid velocity in 100 μm wide and 100 μm deep micro-channels of ppAc deposited O-MFD was increased by a factor of 10 relatively uncoated surfaces. The mixing of 10% of blood in the water has showed a decrease of about 100 μm/s in the fluid velocity relative to water and 10% red colour dye mixed water. The decrease in the fluid velocity of blood mixed water showed the possibility of blood cells interaction with the highly functional ppAc surfaces of micro-channel in O-MFD and that could have advantages in biological fluids (such as protein) separation.     

Heat Transfer Analysis of Sterilization of Canned Milk Using Computational Fluid Dynamics Simulations

A uniform and effective heat distribution inside the canned milk is very crucial for achieving effective sterilization. It is extremely difficult to establish the temperature profile inside the canned milk during continuous industrial scale operation. Computational fluid dynamics （CFD） simulation can be a useful tool to determine the temperature distribution of the fluid inside the can during the sterilization process. A CFD model was developed for the sterilization of canned milk at 121 ~C. The simulation results were validated with the experimental measurements of temperatures. The formation and movement of slowest heating zone （SHZ） during the sterilization process was tracked. Moreover, effect of can position （vertical and horizontal） during processing on milk temperature distribution inside the can was also investigated. Higher Grashof and Rayleigh numbers were obtained for vertical positioning of can compared to horizontal can processing. Further, effectiveness of the process was calculated based on F-value and these results reinforced the positive effect of horizontal position of can during the sterilization process.     

Optical investigations on indium oxide nano-particles prepared through precipitation method

Visible light emitting indium oxide nanoparticles were synthesized by precipitation method. Sodium hydroxide dissolved in ethanol was used as a precipitating agent to obtain indium hydroxide precipitates. Precipitates, thus formed were calcined at 600 °C for 1 h to obtain indium oxide nanoparticles. The structure of the particles as determined from the X-Ray diffraction pattern was found to be body centered cubic. The phase transformation of the prepared nanoparticles was analyzed using thermogravimetry. Surface morphology of the prepared nanoparticles was analyzed using high resolution-scanning electron microscopy and transmission electron microscopy. The results of the analysis show cube-like aggregates of size around 50 nm. It was found that the nanoparticles have a strong emission at 427 nm and a weak emission at 530 nm. These emissions were due to the presence of singly ionized oxygen vacancies and the nature of the defect was confirmed through Electron paramagnetic resonance analysis.     

Leukemia cells interaction with plasma-polymerized acrylic acid coatings

The acrylic acid (ppAc) films were deposited on a glass substrate by plasma polymerization. The interaction of leukemia cells with the ppAc films was studied. It was found that the leukemia cells showed a higher growth on cell culture polystyrene and microscope cover glass substrates, whereas a low growth (about 60%) on the ppAc films. The presence of functional groups such as hydroxyl and carbonyl on the ppAc films can affect the cell culture.     

Using low-pressure plasma for Carthamus tinctorium L. seed surface modification

Low-pressure RF argon gas discharge was used for surface modification of Safflower (Carthamus tinctorium L. semen) to increase the germination rate and activity and reduce the germination time. The results showed that plasma-treated C. tinctorium L. semen has 50% higher germination rate, 100% increase in the activity and 24 h reduction in germination time relativeto untreated. The effect of two different pressure plasma treatments at constant power and exposure time were also investigated. The result showed that the low-pressure plasma treatment was a more effective way to increase the germination rate at a smaller plasma treatment time. Using scanning electron microscope (SEM), the surface structure of plasma-treated and untreated C. tinctorium L. semen has been characterised. The SEM observations of Carthamii pericarpium and Hilum showed a change in the surface structure after plasma treatment. The physical structure of Carthamii pericarpium after plasma treatment looks softer relative to untreated. The Hilum of untreated C. tinctorium L. semen showed a very nice structure and boundary layer whereas after plasma treatment the structure was modified.