(600e) Numerical Coarse-Graining of Polymer Field Theories

Field theoretic models are widely used to investigate self-assembly and phase behavior of heterogeneous polymeric materials, particularly block copolymers. Numerical methods for these models often increase computational speed by neglecting fluctuation physics, an approximation that is very accurate for long-chain polymer melts but which breaks down for some systems of engineering interest, including polyelectrolytes and dilute polymer solutions. Methods that accurately handle these fluctuating systems, such as the complex Langevin method, are computationally demanding; to improve the efficiency of these methods and permit study of larger systems, we propose the use of systematically coarse-grained field theories that can be simulated on coarsely-spaced simulation lattices without truncation of important short-wavelength physics. We present a flexible and rigorously founded variational framework for parameterizing such coarse-grained models from fine-grained simulation data, and results from the application of this formalism to some model polymeric systems.