Elements: Open-source tools for block polymer phase behavior

Block polymers are molecules formed by bonding one or more different polymer molecules at their ends. When a liquid of block polymers is cooled, it spontaneously forms an ordered structure with nanoscale domain sizes and a structure that is dictated by the chemistry of the block polymer. Understanding the selection of different ordered states has both fundamental and practical implications. On the fundamental side, block polymers provide an important model system for examining self-assembly and the formation of crystalline order in soft matter. At a practical level, the ability to construct materials with a controllable arrangement of components with dramatically different properties (e.g., glassy spheres embedded in a rubbery matrix) enables novel applications. Computation plays an important role for both fundamental studies and these technological applications by providing guidance towards the selection of materials to analyze and a framework for interpreting the results. This project will produce an open-source software package that enables block polymer researchers to easily use state-of-the-art computational tools in their own research. The long-term goal of the project is to achieve, within the context of the block polymer theory and experimental community, a widespread use of field-based simulation tools that naturally complement particle-based molecular dynamics simulation methods for studying block polymer properties. This project also provides graduate students and undergraduates with the opportunities to work on state-of-the-art simulation methods and training in high-performance scientific computing.

The proposed open-source software package will enable self-consistent field theory (SCFT) and field theoretic simulations (FTS) under a common framework implemented in C++. The package will include SCFT tools that build on the successful Polymer Self Consistent Field (PSCF) software package for periodic systems to provide the full suite of functionality required for advanced polymer physics research. This new package, entirely rewritten in a new language and with a more flexible design, will enable accelerated calculations on either GPUs or multicore CPUs, efficient treatment of problems with special symmetries, and treatment of complex boundaries such as polymer-grafted nanoparticles and patterned surfaces. A separate set of FTS programs will allow the user to implement either complex Langevin sampling of the fully fluctuating model or a more efficient form of stochastic simulation that involves an approximate treatment of non-specific steric interactions that maintain a uniform density. Input/output tools will also be developed to lower the barrier to usage of the software. Dissemination of the work will include a project website, which will provide background for potential users and links to documentation, and an online tutorial workshop that will introduce the software and its capabilities to the broader community.

This project is funded by the Office of Advanced Cyberinfrastructure in the Directorate for Computer and Information Science and Engineering, with the Division of Materials Research and the Division of Chemistry in the Directorate for Mathematical and Physical Sciences and the Division of Chemical, Bioengineering, Environmental and Transport Systems in the Directorate for Engineering also contributing funds.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.