  We present the results of a quantitative study of the phase behavior of a
model polymer chain with side spheres using two independent computer simulation
techniques. We find that the mere addition of side spheres results in key
modifications of standard polymer behavior. One obtains a novel marginally
compact phase at low temperatures, the structures in this phase are reduced in
dimensionality and are ordered, they include strands assembled into sheets and
a variety of helices, and at least one of the transitions on lowering the
temperature to access these ordered states is found to be first order. Our
model serves to partially bridge conventional polymer phases with biomolecular
phases.
