The structure of a Ginzburg-Landau (GL) model originally introduced to model superconductivity can be extended to describe a variety of other physical phenomena that involve ordered systems. The GL theory is particularly useful for understanding the behavior of structural defects - the regions of disorder that appear, e.g., for topological reasons. In my talk, I will discuss a macroscopic level GL-type model that arises in continuum mechanics of carbon nanotubes. The focus will be on establishing a connection between the coarse-grained model and its atomistic counterpart.