International Journal of Nanoparticles (10 papers in press)
- Effect of Cross Sectional Geometry on Band Gap of Silicon Nanowires
by sana kausar, shirish joshi
Abstract: The electronic properties of very thin Silicon nanowires of different shapes were studied by ab-initio method using the generalized gradient approximation. We consider four different shapes of nanowires viz triangular, rectangular, pentagonal and hexagonal wire. The geometry optimization and the band gap of all nanowires were investigated. SiNWs exhibiting different patterns at the cross section show significant difference in their band gaps indicating that the electronic structures of SiNWs are much more sensitive to surface modification and the change of cross section. The present study reveals that band gap of a nanowire depends on cross sectional geometry not on cross sectional area.
- Structural and optical properties of undoped and Mn-doped SnO2 nanoparticles by hydrothermal method
by Gajendiran jayapal, V. Rajendran
Abstract: Abstract: Undoped and Mn-doped tin oxide (SnO2) nanoparticles were synthesized, using precursors such as tin salt, and alkali hydroxide as a mineralizer via a simple hydrothermal method. X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), High-resolution TEM (HR-TEM), Energy dispersive X-ray spectra (EDX), UVvis absorption spectra and photoluminescence (PL) spectra were used to characterize the undoped and Mn-doped SnO2 samples. The confirmation of the nanoparticles size and the nanocrystalline nature of SnO2 samples was carried out, using TEM and Selected Area Electron Diffraction (SAED), respectively. The EDX analysis proved the presence of Mn ions into the SnO2 sample. The band gap energy of the undoped (3.90eV) and Mn-doped SnO2 (3.95eV) samples is estimated from the UV-visible absorption spectra, and may be used in optoelectronic devices. The mechanism for the hydrothermal synthesis of the SnO2 nanoparticles is also discussed.
Keywords: Nanostructures, Semiconductors, X-ray diffraction, Optical properties
- CALORIMETRIC STUDY OF NANOCOMPOSITES OF EPOXY NETWORK DGEBA n=0/m-XDA WITH GOLD NANOPARTICLES
by Francisco Fraga-López, Eugenio Rodríguez-Núñez, Adrian Martínez, Javier Miragaya
Abstract: The optimization of cure conditions for epoxy system diglicidil ether of bisphenol A (DGEBA n=0)/ meta-xylylenediamine (m-XDA) has been made using experimental design. A quantitative analysis by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) as well as making of nanocomposites of epoxy system with gold nanoparticles have been carried out. The knowledge of the optimum values for the variables of experimental design obtained with DSC in the system BADGE/m-XDA allows to study the adequate conditions of the nanocomposites curing process. DSC was used to measure the glass transition temperture (Tg) and the degree of conversion (α). The FTIR method should be a more precise indicator of degree of conversion than DSC and it was used to corroborate the degree of conversion.
Keywords: differential scanning calorimetry (DSC); diglicidil ether of bisphenol A (DGEBA); gold nanocomposites
- A promising approach to enhanced thermal stability of DC conductivity of Polyaniline- Functionalised multiwalled carbon nanotube composites
by Sobha. A.P, Sunil Narayanankutty
Abstract: Nanocomposites of Polyaniline and 4-aminobenzoyl functionalised Multiwalled Carbon Nanotubes (PANI-FMWCNT) were synthesised through interfacial polymerisation of aniline in presence of FMWCNT and protonating with inorganic acids like Hydrochloric acid (HCl), Sulfuric acid (H2SO4) and organic sulfonic acids like Paratoluenesulphonic acid (TSA), Naphthelene-2-sulfonic acid(NSA). Samples of neat polyaniline were also synthesised. The composites were characterised by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA). The high temperature DC conductivity stability was investigated through cyclic accelerated ageing and isothermal ageing studies. The morphology studies indicated that pure PANI had a nano fibrillar structure while composite had a core shell structure consisting of carbon nanotube having an ordered, uniform encapsulation of polyaniline. Composites exhibited improved thermal stability over neat PANI. Covalent grafting and strong interaction between polymer chains and nanotubes resulted in additional thermal stability of composites. On thermal cyclic treatment up to 150
Keywords: DC conductivity; Functionalised multiwalled carbon nanotubes; Interfacial polymerisation; Polyaniline; Thermal stability; cyclic ageing; Isothermal ageing
- Synthesis and characterization of double walled Carbon nanotube/cobalt oxide nanacomposite for the application of anode material for lithium ion batteries.
by Omar A.Al-Hartomy
Abstract: This paper presents a novel description of synthesis and characterization of doubled walled carbon nanotube/cobalt oxide nanacomposite for its application as an anode material for lithium ion batteries. Synthesis of nanostructures with controlled morphology continues to be a major issue in nanoscale science. Double wall carbon nanotubes (DWCNTs) are synthesized using a simple flotation chemical vapor deposition technique by adding a small amount of sulfur into the catalyst. The structural, compositions and morphology of the as synthesized doubled walled Carbon nanotube/cobalt oxide nanacomposite is performed using XRD, FESEM, EDS and HRTEM. A 500 MHz NMR spectroscopy is used to analyze NMR spectrum. The small cell made of such core-shell structure of nanocomposite shows lithium storage of 1530 mAh/g (milli ampere hour per gram), normally the electromotive force which stores inside the cell in the form of electric potential energy converted in the work output. The capacity of such cell is found to be 1225 mAh/g over 100 cycles. The cell is found to be more efficient than traditional cell available in the market.rn
Keywords: Doubled walled carbon nanotubes; Lithium ion battery; Electrochemical reaction.rn
- Effect of annealing on metal-insulator transition of VO2 (M) nanorods
by Ying Luo, Ming Li, guanghai li
Abstract: The influence of annealing treatment on the metal-insulator transition (MIT) of VO2 (M) nanorods was studied. The phase structure and content of the products were analyzed by X-ray diffractometer (XRD), and the MIT was analyzed by differential scanning calorimeter (DSC). It was found that VO2 (M) nanorods have uneven thickness and round tip in comparison with a uniform thickness and sharp tip in VO2 (B) nanorods, and there are two MITs in the DSC curves in the phase mixture of VO2 (M) and VO2 (B), one is situated at low temperature region and another is at high temperature side, and the high temperature MIT exists only in pure VO2 (M) at annealing temperature of 550
Keywords: vanadium dioxide; nanorods; annealing treatment; metal-insulator transition, thermochromic
- Antibiofouling property of marine actinobacteria and its mediated nanoparticle
by Aditi Agarwal, Avani Mehra, Loganathan Karthik, Gaurav Kumar, K.V. Bhaskar Rao
Abstract: The study focused on the combination of marine actinobacterial extract and its mediated zirconium oxide nanoparticles for anti-biofouling application against the isolated biofouling bacteria. Streptomyces sp.VITSDSB was used for the synthesis of zirconium oxide nanoparticles, since it showed the maximum potential for the synthesis of nanoparticles. The biosynthesized nanoparticles were characterized using UV-visible spectra (UV-vis), X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR) and High resolution transmission electron microscopy (HRTEM), where the biosynthesis of square shaped zirconium oxide nanoparticles with size 20nm was confirmed. The antibiofouling property of nanoparticles against the isolated biofouling bacteria was checked, where a combination of actinobacterial extract and nanoparticles with paint showed maximum effect against Bacillus thuringiensis and Pseudomonas aeruginosa. Nanoparticles in a concentration of 100 mg/ml showed more than 50% lethality against brine shrimp eggs. Nanoparticles in combination with marine actinobacterial extract were also observed to have enhanced anti-corrosion activity against salt water and acid.
Keywords: Zirconium Oxide, Square shaped nanoparticles, Antifouling, Marine Actinobacteria
- Development of chlorophyll-protein complex nanoparticles for light harvesting and solar cell application
by Aneesha Kondapi, Golla Kishore, Farhan Ahmed, Anand Kumar Kondapi
Abstract: Principal components of photosystem involves light reception in plants are chlorophyll protein complexes. In the present study, we have employed chlorophyll protein complexes nanoparticles for photoreception with an aim to assess the excitation like behavior of these complexes when used in nanoparticle form for the development of photovoltaic devices. As a result of Photon interaction with chlorophyll protein complexes initiate electron emission thus convert it into electron deficient center. Consequently these electrons are transferred to electronic sink fullerene nanoparticle, makes it electron efficient, thus providing a natural photocell comprising electron deficient chlorophyll protein complexes nanoparticles as positive electrode and electron efficient fullerene as negative electrode. A comparative analysis of results for different plant species showed significant potential difference in such natural photocells developed with nanoparticles of chlorophyll protein complexes.
Keywords: Solar cell; nanoparticles; chlorophyll; fullerene; photosynthesis
Special Issue on: "
Nanotechnology Challenges 2014 "Nanotechnology Imperatives in the New Millennium,"
- A Simple Method to Prepare Superhydrophobic Polypropylene Coatings for Biomedical Applications
by Rafik Abbas, Wagih Sadik, Abdel Ghaffar El Demerdash, Adel Badria
Abstract: In this paper, a simple method of preparing superhydrophobic self-cleaning polypropylene coating for biomedical applications is reported. The effect of several factors on the preparation of superhydrophobic polypropylene (PP) surfaces has been studied. These factors include PP concentration, heating rate for PP dissolution, the solvent evaporation rate and the addition of different amounts of TiO2 nanoparticles. The prepared PP was studied by contact angle, SEM, FTIR, and DSC measurements. This study showed that the best suitable parameters for PP superhydrophobic surface formation were found to be 40 mg/ml of PP in xylene concentration, 3.5oC/min dissolution heating rate and 70oC curing temperature. Superhydrophobic Polypropylene surfaces incorporating TiO2 nanoparticles have been successfully synthesized via the adopted method. Static contact angle of 165◦ was achieved. Also preliminary biological studies, including bacteria antisticking effect and ISO cytotoxixcity, have been investigated. The antisticking effect of the superhydrophobic surfaces showed a significant positive result against S. aureus bacterial suspension.
Keywords: Superhydrophobicity, Polypropylene, TiO2 Nanoparticles, Nanocomposites, S. aureus bacteria, Bacteria Adhesion, ISO Cytotoxicity
- Photoluminescence, Magnetic and Electrical Properties of Co-Ferrite Nanoparticles Synthesized Via Solgel Auto-combustion Method
by Nema Imam, Salwa Ismail, Mohammed Elbahrawy, Adel Hashhash
Abstract: Herein, we report magnetic, photoluminescence and electric properties for CoFe2O4 (CFO) nanoparticles. The CoFe2O4 was prepared by a citrate auto-combustion method. X-ray diffraction confirmed the crystallization of pure CoFe2O4 phase with an average size of about 27 nm. The FT-IR spectrum confirmed the intrinsic cation vibrations for the spinel structure. Magnetization values for CoFe2O4 nanoparticles are lower when compared to the literature values for bulk samples. The variation of dielectric constant, dielectric loss tangent and AC conductivity for CoFe2O4 nanoparticles at different temperature and as a function of frequency has been studied. The results revealed that the magnetic properties depend on the particle size and cation distribution, whereas the role of particle size is more significant. The data from vibrating sample magnetometer (VSM) and photoluminescence (PL) have been analyzed for exploring their applications.
Keywords: Spinel ferrites; synthesis; Characterization; Magnetic Properties