  The steepest-entropy-ascent quantum thermodynamic (SEAQT) framework is
utilized to study the effects of temperature on polymer brushes. The brushes
are represented by a discrete energy spectrum and energy degeneracies obtained
through the Replica-Exchange Wang-Landau algorithm. The SEAQT equation of
motion is applied to the density of states to establish a unique kinetic path
from an initial thermodynamic state to a stable equilibrium state. The kinetic
path describes the brush's evolution in state space as it interacts with a
thermal reservoir. The predicted occupation probabilities along the kinetic
path are used to determine expected thermodynamic and structural properties.
The polymer density profile of a polystyrene brush in cyclohexane solvent is
predicted using the equation of motion, and it agrees qualitatively with
experimental density profiles. The Flory-Huggins parameter chosen to describe
brush-solvent interactions affects the solvent distribution in the brush but
has minimal impact on the polymer density profile. Three types of
non-equilibrium kinetic paths with differing amounts of entropy production are
considered: a heating path, a cooling path, and a heating-cooling path.
Properties such as tortuosity, radius of gyration, brush density, solvent
density, and brush chain conformations are calculated for each path.
