Carbon Nanotubes and Related Structures

Carbon nanotubes have attracted the fancy of many scientists world wide. The small dimensions,strength, and the remarkable physical properties of these structures make them a unique material with a whole range of promising applications. In this review, the structural aspects, the advantages and disadvantages of different for their procedures synthesis, the qualitative and quantitative estimation of carbon nanotubes by different analytical techniques, the present status on their applications as well as the current challenges faced in the application field, national, in particular DRDO, DMSRDE status, and interest in this field, have been discussed.Defence Science Journal, 2008, 58(4), pp.437-450, DOI:http://dx.doi.org/10.14429/dsj.58.166

Synthesis of Silver Nanostructures and their Application in Highly Sensitive SERS Sensors

A comparison of Surface Enhanced Raman Scattering (SERS) activity of chemically synthesised silver nanostructures with different shapes is reported. The silver nanostructures of cubical, prism and wire like morphology were synthesised using chemical synthesis route and utilised as SERS substrates. The sensors were fabricated by spin coating these materials over a Silicon or glass substrate. The fabricated sensors were used to analyse response with two different analytes, 4-Mercaptobenzoic acid and Rhodamine 6G under different concentrations. The signal enhancement was compared with a silver coated thin film over glass substrate and it was observed that the enhancement of the order of 103 is achieved. The nanowire performed better than the other forms of silver and gave a higher signal enhancement for all the analytes as compared to other nanostructures. The fabricated sensors may be useful for various applications including explosive and biowarfare agent detection

Systematic investigation of close-packed silica nanospheres monolayer under sintering conditions

In this paper, we have quantified and investigated the effect of various sintering temperature on close-packed Silica Nanospheres (SNs) monolayers. SNs with diameters of 140, 175 and 220 nm were fabricated by an effective and reliable spin-coating technique. The fabricated SNs monolayers were sintered up to 1200 °C and were analyzed from FESEM to investigate in details for local and extended transformations in their structural and morphological properties. A distinct "neck-formation" was observed and was quantified with different particle size distribution as well as surface packing density. It was observed that SNs monolayer undergoes intra-particle reformation in the form of shrinkage in individual SNs and compactification of growth domains, followed by inter-particle sintering. A geometrical model was developed to determine the curvature radius and interpenetration depth thus enabling us to quantify the parameters that dominate the dynamics of the sintering process for such non-porous SNs.by Sakshum Khanna, Utsav Harsh Chaliyawala, Sagar Paneliya, Debmalya Roy, Kingsuk Mukhopadhyay, Rupak Banerjee and Indrajit Mukhopadhya

Effect of Reinforcement at Length Scale for Polyurethane Cellular Scaffolds by Supramolecular Assemblies

This study is aimed to represent the role of carbonaceous nanofillers to reinforce the commercially available polyurethane porous structure. The effect of dimensionality of fillers to anchor the construction of stable three-dimensional (3D) cellular architectures has been highlighted. The cellular frameworks of commercially available thermoplastic polyurethane (TPU) have been fabricated through the thermoreversible supramolecular self-assembly route. It was established that the minimum shrinkage of TPU lattice structures occurred when the solid-state network is strengthened by the topologically engineered 3D hierarchical nanofillers, where the amount of reinforcement was found to play a critical role. It has been established by series of structure–property correlations that reinforcing the cellular structure to endure the capillary stress is equally effective as supercritical drying for producing low-density porous morphologies. The removal of liquid phase from gel is as important as the presence of 3D fillers in the matrix for reinforcing the cellular structures when replacing the solvent phase with air to generate a two-phase solid–gas engineered morphology. The insight into the polyurethane network structure revealed that the dimensionality, amount, and distribution of fillers in the matrix are critical for reinforcing the cellular scaffolds in solid gel without any cross-linking