This paper investigates the effect of temperature on the elastic modulus of carbon nanotube-polyethylene (CNT-PE) nanocomposite and its interface using molecular dynamics (MD) simulations, by utilizing the second-generation polymer consistent force field (PCFF). Two CNTs-armchair and zigzag-were selected as reinforcing nano-fillers, and amorphous PE was used as the polymer matrix. For atomistic modelling of the nanocomposite, the commercially available code Materials Studio 8.0 was used and all other MD simulations were subsequently performed using the open source code Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). To obtain the elastic modulus of the nanocomposite, stress-strain curves were drawn at different temperatures by performing uniaxial deformation tests on the nanocomposite material, whereas the curvatures of the interfacial interaction energy vs. strain curves were utilized to obtain Young's modulus of the interface. In addition, the glass transition temperatures of the polymer matrix and nanocomposites were also evaluated using density-temperature curves. Based on the results, it is concluded that, irrespective of temperature condition, a nanocomposite reinforced with CNT of larger chirality (i.e., armchair) yields a higher value of Young's modulus of the nanocomposite and its interface. It was also found that, at the phase transition (from a glassy to a rubbery state) temperature (i.e., glass transition temperature), Young's moduli of the polymer matrix, nanocomposite, and its interface drop suddenly. The results obtained from MD simulations were verified with results obtained from continuum-based rule-of-mixtures.

We report the formation of nanoparticles of silicon (thread-like nanostructures of diameter approximately=2 nm and length a few microns, as if nanocrystals are linked together along curly tubules), the occurrence of a tubule-like configuration, whiskers and a new phase with large periodicity, a=14.25 AA, f.c.c. silicon, when evaporated under helium ambience (100 Torr) and characterized through transmission electron microscopic techniques, revealed several curious characteristics as mentioned above. We have suggested the possibility of a new phase with a=14.25 AA for the f.c.c. lattice, being formed by an assembly of Si28 clusters. The geometrically calculated lattice parameter of the f.c.c. lattice resulting from an assembly of Si28 clusters is in reasonable agreement with the observed lattice parameter.

The present study investigates the interfacial behavior of functionalized carbon nanotube-polyethylene nanocomposite at different temperatures using molecular dynamics simulations, utilizing the second-generation polymer consistent force field. The carboxylic acid group is used to functionalize the carbon nanotube. In order to calculate interfacial interaction energy and interfacial shear strength of the nanocomposite, various pull-out tests are performed at different temperatures in the range of 1-400 K. The effect of functionalization on the interfacial interaction energy, interfacial shear strength, and glass transition temperature of the nanocomposite are studied in comparison to pristine carbon nanotube-reinforced nanocomposite. Results reveal that for all temperatures and degrees of functionalization, the chirality (i.e. armchair and zigzag) of carbon nanotube has a significant effect on interfacial interaction energy and interfacial shear strength of the nanocomposite. It is also found that functionalizing the carbon nanotube in carbon nanotube-polyethylene nanocomposite enhances its interfacial shear strength at different temperatures. Furthermore, a sudden drop in the value of interfacial interaction energy and interfacial shear strength of the pristine as well as functionalized carbon nanotube-reinforced nanocomposite is observed at a temperature near to its glass transition temperature.

We report the formation and characterization of nanoparticles and their assemblage to form a threadlike microstructure of silicon, germanium and tin, by the process of thermal deposition in helium ambient under varied conditions of pressure. The structural characterization of the nanoparticles was done by transmission electron microscope (Philips CM12). Resistance versus temperature (R -T ) measurements, on the thin films embodying nanothreads, exhibited anomalous behaviour embodying erratic changes in R -T variations. This was suggestive of variation of nanoparticle distribution with increase in temperature.

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