A field theoretic approach for simulating assemblies of interacting polymers is discussed. By applying a Hubbard-Statonovich transformation to a molecularly informed coarse-grained polymer model, auxiliary fluctuating fields are introduced to decouple segmental interactions, and particle degrees of freedom are integrated out. The resulting theory has several advantages for simulating polymeric systems, including direct access to mesoscale phenomena without simulating the atomic/molecular scale. The theory is commonly employed in the mean-field limit (SCFT), which is exact for asymptotically long polymer chains in the melt state. However, for intermediate-molecular-weight melts, for solvated or charged polymers, or for systems close to critical phase transitions, the mean-field approximation is qualitatively inadequate. We discuss a stochastic computational method based on complex Langevin sampling to directly simulate the fully fluctuating field theory without critical inefficiencies of the sign problem, and present details of the latest numerical algorithms for achieving stable, efficient and accurate sampling.Several applications of the theory are discussed, including a free-energy method based on thermodynamic integration for accessing phase transitions; systematic numerical coarse graining of the field theory as a framework for multi-scale modeling; and a new field-theoretic formalism based on coherent states, rather than auxiliary fields, which is more amenable to the systematic generation of trial field-theoretic actions for coarse graining.

Progress in fully fluctuating field-theoretic polymer simulations

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.