  We study the effects of two kinds of interactions in tube-like polymers and
demonstrate that they result in the formation of secondary motifs. The first
has an entropic origin and is a measure of the effective space available to the
solvent. The second arises from solvophobic interactions of the solvent with
the polymers and leads to an energy proportional to the contact surface between
the tube and solvent particles. The solvent molecules are modeled as hard
spheres and the two interactions are considered separately with the solvent
density affecting their relative strength. In addition to analytical
calculations, we present the results of numerical simulations in order to
understand the role played by the finite length of short polymers and the
discrete versus continuum descriptions of the system in determining the
preferred conformation.
