Conformational mechanics for polymers doubly-grafted to a homogeneous substrate

Studies of linear polymer structures with their two ends anchored at a planar substrate can help to provide insights into conformational properties of biologically active systems such as myosin and kinesin. We thoroughly investigated the conformational phases of a coarse-grained flexible homopolymer model with both ends of the chain grafted to a homogeneous attractive substrate by means of parallel tempering computer simulations. For bonded monomers, we employed the FENE potential, whereas the nonbonded interaction was described by the Lennard-Jones potential. The monomer-substrate attraction was modeled using an integrated Lennard-Jones potential. Specific energetic and structural quantities were measured and used as indicator functions for the characterization of the conformational phases in this system. Based on these results, we constructed the temperature versus end-to-end separation pseudo-phase diagram. We identified unique crystalline and icosahedral solid phases in addition to a globular liquid and two geometric gas-like phases.