In this pape effect of nanotube aggrates on the rheological properties of multiwall carbonanntube abd epoxy suspension in epoxy resin.The base epoxy resin was found to be essentially Newtonian, and the progressive incorporation of nanotubes enhanced the low shear rate viscosity of the suspension by nearly two decades. At higher shear rates, the suspension viscosity asymptotically thinned to the viscosity of the matrix alone. The low shear rate viscosity enhancement was correlated with the optical observations of interconnected aggregates of carbon nanotubes, which themselves were induced by the low shear conditions. Intermediate shear rates resulted in a reduction in the size of the aggregates. High shear rates appeared to cause near complete dispersal of the aggregates. From these results it is conjectured that for this suspension, shear thinning is connected with the breaking of the interconnected network between aggregates of nanotubes, and not by nanotube alignment.

Hen egg white lysozyme (HEWL) was exposed to various physical and chemical denaturing environments to encourage protein denaturation and consequent gelation. Its phase behavior was examined as a function of pH, temperature and also in the presence of the reductant dithiothreitol (DTT). Transparent viscoelastic gels form at low pH values while opaque gels form under alkaline conditions. No increase in viscosity was observed for systems in pure water unless 20 mM of DTT was added, which is known to break the disulfide bridges present in HEWL. The microstructure of the gel was studied using transmission electron microscopy (TEM) and environmental scanning electron microscopy (ESEM). Gels formed at low pH contain fibrils ∼10 nm in diameter with various lengths while at high pH the gels are dominated by particulate aggregates. Thinner fibrils that are 4-6 nm in diameter are observed in the gels formed in the presence of DTT. In this case the distinct feature of the gels is they are thermoreversible and can be melted and reformed easily by varying the temperature.

While carbon nanotubes (CNTs) possess diverse application potential ranging from polymer nanocomposites to nanostructured therapeutic devices, their environmental implications are still not well understood. In this study, we conducted experiments to monitor changes in bacterial physiology as a consequence of interactions with the CNTs. Our experiments included a common anaerobe, Escherichia coli, in an SWNT system as a model for understanding the environmental implications of CNTs. Observations over several weeks indicated that the bacteria in the presence of SWNTs showed significant morphological changes, that included elongation. It is interesting to note that similar morphological changes have been reported in response to extreme temperature and pressure, chemical agents, and quantum dots. In this presentation, the authors will present further physiological evidence, such as bacterial growth and substrate consumption rates, towards defining a possible bacteria-CNT interaction model consistent with these experimental observations, and will discuss the overall environmental implications.