(342d) Dynamic Phase Field Models for Polymeric Liquids

Industrial processes for producing polymer-based materials often operate away from equilibrium, making the final microstructure dependent on the processing history. Because material properties are intrinsically tied to microstructure, we assert that tools capable of simulating microstructural evolution will play a crucial role in better understanding and predicting the material properties of polymeric materials. While traditional fluid dynamics models can capture the bulk transport behavior of such processes, such methods typically fail to address the complex phase behavior characteristic of many polymeric liquids. Dynamic simulations of coarse-grained models are a well-known technique to overcome this limitation, but such methods are often severely constrained in the length and time scales they can explore. Consequently, we explore an alternative simulation framework based on the so-called "two-fluid" model originally proposed by Brochard and de Gennes. In this framework, we derive a prototypical example of a three-component polymer solution using a formalism for non-equilibrium thermodynamics at low-Reynolds number developed by Doi and Onuki. We proceed to develop numerical methods capable of simulating this model, and demonstrate that it is indeed possible to simulate the microstructural evolution of polymeric materials on large length scales with non-trivial phase behavior.