High pressure isothermal equation of state for nanomaterials

A simple theoretical model is developed to study the high pressure behavior of carbon nanotubes viz. single-wall carbon nanotube bundle, single-wall individual carbon nanotube, α-Fe filled multi-wall carbon nanotube and Fe₃C filled multi-wall carbon nanotube. On comparing with the experimental findings as well as the Shanker, Usual Tait and Murnaghan equation of states, the present model gives the better results than the other relations. The model is also extended to study the high pressure behavior of bulk modulus for carbon nanotubes. The present study reveals that for nanomaterials, it is a good approximation to consider the pressure to be quadratic in the density. (author)