  A simple model of a polymer with long rigid segments which interact via
excluded volume repulsions and short ranged attractions is proposed. The
coil-globule transition of this model polymer is strongly first order, the
globule is crystalline and the coil which coexists with the globule is swollen.
A virial expansion truncated at low order is shown to provide a very poor
approximation to the free energy and so a cell theory is used to calculate the
free energy of the globule.
