Simulations of an off-lattice model for polymers doubly grafted to a homogeneous substrate

Conformational phases of an off-lattice flexible homopolymer model with both ends attached to
a homogeneous attractive substrate were investigated by means of parallel tempering simulations.
We employ a coarse-grained polymer-substrate model, which is based on the FENE potential
for bonded monomers, whereas the monomer-monomer interaction is governed by the
Lennard-Jones potential. The monomer-substrate attraction is modeled using an integrated
Lennard-Jones potential. Thermodynamic and structural quantities help to characterize
the conformational phases of this system. With this information, the complete
solubility-temperature phase diagram can be constructed and discussed. We investigate
the adsorption strength that separates the phase diagram into two main phases of
adsorbed and desorbed conformations. Other phases formed by energy-dominated
crystalline low-temperature structures and globular entropy-dominated conformations
are of particular interest in this study.