Polymer Physics Across Scales: Bridging Atomistic and Coarse-Grained Polymer Models

Stanford University, Stanford CA

Investigators

Abstract

NONTECHNICAL SUMMARY This research project is aimed to develop theoretical and computational approaches to modeling soft polymeric materials across scales of length from the individual molecules to the scales of bulk materials. Polymeric materials are ubiquitous in our daily lives, and they play a significant role in virtually every technological area. The current predictive framework for the behavior of soft polymeric materials can be divided into two different philosophical approaches. The first is based on detailed models down to the level of atoms; these are frequently computationally intractable for exhaustive discovery of polymeric materials. The second, more computationally tractable approach, is based on low resolution representations of polymers from which general predictions of physical behavior can be made, but at the expense of molecular-level detail. This research project is aimed to build a roadmap for bridging between these disparate perspectives that leverages the strength of each approach while avoiding their individual shortcomings. The goal is to enable the study of a wide range of properties of polymeric materials that were previously impossible to capture. This research project also provides a platform for training theorists and computational scientists who will be able to tackle a diverse range of fundamental and applied problems in soft materials. The research and educational goals of this project are complemented by broader outreach through the development of a dynamic program called LABScI. Laboratory Activities for Broadened Scientific Instruction. This program develops and implements laboratory science and engineering teaching modules for the education of high school students that are being treated for childhood cancer and other illnesses. This program is piloted at the Hospital School at the Lucile Packard Children's Hospital with engagement from undergraduate and graduate students at Stanford to develop the program. Ongoing efforts aim to broadly disseminate this program nationally as a general laboratory science curriculum for hospital-school education. Towards this goal, this project will develop videos and online teaching aids that further enable the implementation of the labs. TECHNICAL SUMMARY This research project is aimed to develop theoretical and computational approaches to modeling soft polymeric materials across scales of length from the individual molecules to the scales of bulk materials. Current understanding of polymeric materials is largely based on coarse-grained models, but the development of high-performance computational simulations offers new levels of granular detail that would be invaluable for materials development. Bridging these scales is a hallmark problem in soft-materials physics. The PI aims to systematically incorporate varying levels of detail to capture the multi-scale behavior in polymeric materials. The foundational work in this research program will offer new and critical insight into the mesoscopic behavior of polymeric materials, which is a crucial length scale for many material phenomena for technological applications. This project aims to tackle key problems in soft materials self-assembly and thermodynamic behavior that require bridging these disparate perspectives through identifying an intermediate-scale physical model that is amenable to theoretical analysis while containing sufficient granular detail to compare with a detailed model. Semiflexible polymers are defined to have a level of detail that bridge these two perspectives, and fundamental work in describing the statistical behavior of such materials acts as critical input in this theoretical effort. This research program addresses the physical behavior of semiflexible polymer solutions and materials by (1) building a software package to predict the thermodynamic behavior of semiflexible polymers, (2) predicting the impact of semiflexibility and fluctuations in copolymer materials exhibiting structural and liquid-crystalline order, and (3) determining the impact of polymer and solvent ordering in the phase behavior of polyelectrolyte materials. These key areas of exploration provide deliverable tools and results that interface directly with existing theoretical, computational, and experimental approaches in soft materials. This effort may also shed new light on how granular molecular interactions influence the mesoscopic behavior in soft polymeric materials. This research project also provides a platform for training theorists and computational scientists who will be able to tackle a diverse range of fundamental and applied problems in soft materials. The research and educational goals of this project are complemented by broader outreach through the development of a dynamic program called LABScI. Laboratory Activities for Broadened Scientific Instruction. This program develops and implements laboratory science and engineering teaching modules for the education of high school students that are being treated for childhood cancer and other illnesses. This program is piloted at the Hospital School at the Lucile Packard Children's Hospital with engagement from undergraduate and graduate students at Stanford to develop the program. Ongoing efforts aim to broadly disseminate this program nationally as a general laboratory science curriculum for hospital-school education. Towards this goal, this project will develop videos and online teaching aids that further enable the implementation of the labs. 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.