Entropy-driven microstructure evolution predicted with the steepest-entropy-ascent quantum thermodynamic framework

Predicting Polymer Brush Behavior in Solvents Using the Steepest-Entropy-Ascent Quantum Thermodynamic Framework

“…A similar extension of the Onsager formalism to the far-from-equilibrium region using the steepest-entropy-ascent hypo-equilibrium formalism has been derived by Li and von Spakovsky . While the steepest-entropy-ascent principle is treated here as a postulate, it has a long history, has a firm mathematical basis, − ,, and has been tested in a wide range of quantum and classical applications. − ,− ,,, Additional discussion of the generality of the steepest-entropy-ascent principle, can be found in refs , , , and .…”

“…SEAQT has seen many recent advancements in its application to various material systems, including those involving magnetism and spin relaxation, thermal expansion, clustering, nucleation, material coupled electron–phonon flows, GaN film growth, , electroporation of cell membrane lipid structures, capillary systems, 2D materials, and polymer folding . SEAQT is unique in that it can predict the nonequilibrium thermodynamic path that a system takes without requiring knowledge of underlying kinetic processes.…”

“…Recent research has established a link between SEAQT paths in state space and physical conformations. , To accomplish this, representative microstructures or conformations are connected to SEAQT-predicted state evolution through the expectation values of a set of structural parameters or descriptors that characterize the microstructure at each time step. These expectation values are computed using the predicted probability distribution, and the arithmetic average values of these parameters are determined for each eigenlevel during the execution of the Wang–Landau algorithm.…”

“…To treat nonequilibrium processes explicitly, this work applies the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework − to determine a brush system’s kinetic path from an arbitrary initial state to stable equilibrium. The framework uses a postulated equation of motion to calculate how energy is redistributed among a brush’s discrete energy levels as it evolves through transition states to equilibrium.…”

“…40 While the steepestentropy-ascent principle is treated here as a postulate, it has a long history, has a firm mathematical basis, [58][59][60][61][62][63]74,75 and has been tested in a wide range of quantum and classical applications. [37][38][39][40][41][41][42][43][44][45][46][47][48][49][50][51][52][53]55,64,65 Additional discussion of the generality of the steepest-entropy-ascent principle, can be found in refs 44, 56, 65, and 66. The present article is structured as follows: The Energetic Model section outlines the energetic model of a polymer brush in a solvent, the Replica-Exchange Wang−Landau section details the construction of the energy eigenstructure for the brush system, the SEAQT Equation of Motion section provides a summary of the basis for the SEAQT equation of motion, and the Linking State Space to Microstructural Evolution section links the kinetic path in the state space to physical microstructures. The results obtained from applying the SEAQT framework to a styrene brush in both cyclohexane and toluene solvents are presented in the Results section.…”