Field-Theoretic Simulations: Coherent States and Particle-Field Linkages

该奖项支持理论、计算和教育，以推进基于聚合物、长链类分子的聚合物材料的计算机模拟。聚合物是一种多功能材料，在纺织品、塑料和橡胶、油漆和涂料以及包括护发产品、清洁剂、洗涤剂等消费品中有着非常广泛的应用。它们在有机太阳能电池等新能源收集技术、电池等能量存储设备中的固体电解质以及先进的药物输送和医疗设备中也越来越重要。也许令人惊讶的是，用于此类应用的新聚合物的设计是通过反复试验进行的，直到分子设计产生目标特性和功能。本项目旨在推进聚合物材料的计算机化设计。该项目的一个组成部分是将聚合物的新理论表示发展成一个计算平台，这将使具有热可逆键的材料的设计成为可能。这些材料具有独特的性能，如损坏时的自我修复，或对热或化学刺激的响应，这在各种新兴应用中都很重要。第二项努力旨在将原子尺度的分子模拟与采用不同理论公式的模拟联系起来，这些模拟可以达到数百微米的尺度。这种能力将使化学细节嵌入到理论模型中；后者提供了链接到聚合物材料的性质。如果成功，这个多长度尺度的建模平台可以大大加快现有和新应用的聚合物的设计。拟议研究的更广泛影响包括项目人员参与理论和计算聚合物科学的研究生，本科生和博士后培训。以理论为导向的学生将通过与加州大学圣巴巴拉分校（UCSB）化学工程、材料和化学实验组的密切合作，接触到更广泛的软材料学科。UCSB的复杂流体设计联盟是一个工业-国家实验室-学术合作伙伴关系，致力于商业相关聚合物配方的计算设计。所有参与者都将为UCSB材料研究科学与工程中心充满活力的教育和推广项目做出贡献。该奖项支持理论和计算，以及教育，以推进聚合物材料的理论和建模。该项目将增强场理论模拟（FTS）方法的能力，允许对聚合物和软材料的场理论模型进行数值研究，而无需诉诸平均场近似。一个项目组成部分建立了一个基于相干态聚合物场论的FTS新平台，这是一个长期被忽视的相互作用聚合物的表现形式，受到量子场论的启发。提出的工作旨在开发和优化算法，以模拟相干态模型，并将这些算法应用于可逆键、超分子聚合物的基础研究。关系将探讨变量，如键的平衡常数，化学计量学和聚合物的结构，自组装行为和热力学性质。相干态框架的独特结构将为FTS内系统粗粒化提供一种新的力匹配方案，适用于超分子和非反应性聚合物体系。提出的研究的另一个组成部分是开发一个工作流，其中使用相对熵最小化将全原子粒子模型映射到粗粒度粒子模型；后一种形式的模型允许解析转换为全参数化的场论。然后，FTS可用于获取与聚合物潜在化学性质直接相关的中尺度结构和热力学性质。拟议研究的更广泛影响包括项目人员参与理论和计算聚合物科学的研究生，本科生和博士后培训。以理论为导向的学生将通过与加州大学圣巴巴拉分校（UCSB）化学工程、材料和化学实验组的密切合作，接触到更广泛的软材料学科。UCSB的复杂流体设计联盟是一个工业-国家实验室-学术合作伙伴关系，致力于商业相关聚合物配方的计算设计。该项目针对的从全原子到FTS的工作流程有可能彻底改变这种配方的硅设计。所有参与者都将为UCSB材料研究科学与工程中心充满活力的教育和推广项目做出贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis award supports theory and computation, and education to advance computer simulation of polymeric materials which are based on polymers, long-chain-like molecules. Polymers are versatile materials that have remarkably broad applications in textiles, plastics and rubbers, paints and coatings, and consumer products including haircare products, cleansers, detergents, etc. They are also increasingly important in new energy harvesting technologies such as organic solar cells, as solid electrolytes in energy storage devices such as batteries, and in advanced drug delivery and medical devices. Perhaps surprisingly, the design of new polymers for such applications proceeds by trial-and-error experimentation until the molecular design yields the targeted properties and function.This project aims to advance in-silico computational design of polymeric materials. One component of the project will develop a new theoretical representation of polymers into a computational platform that will enable the design of materials with thermally reversible bonds. Such materials have unique properties such as self-repair when damaged, or responsiveness to thermal or chemical stimuli, both important in a variety of emerging applications. A second effort aims to link molecular simulations at the atomic scale with simulations that employ a different theoretical formulation and can reach scales of hundreds of micrometers. This capability will enable chemical details to be embedded in the theoretical models; the latter providing the link to polymer material properties. If successful, this multiple length scale modeling platform could dramatically accelerate the design of polymers for existing and new applications.Broader impacts of the proposed research include engagement by the project personnel in graduate, undergraduate, and post-doctoral training in theoretical and computational polymer science. Theoretically-oriented students will be exposed to broader soft materials disciplines through a close coupling with experimental groups at the University of California, Santa Barbara (UCSB) in chemical engineering, materials, and chemistry. Knowledge gained under the proposed project will be leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercially relevant polymer formulations. All participants will contribute to the vibrant education and outreach programs of UCSB's Materials Research Science and Engineering Center.TECHNICAL SUMMARYThis award supports theory and computation, and education to advance theory and modeling of polymeric materials. This project will enhance the capabilities of the field-theoretic simulation (FTS) method, permitting numerical investigations of field theory models of polymers and soft materials without resorting to a mean-field approximation. One project component builds a new platform for FTS based on coherent-states polymer field theory, a long-neglected representation of interacting polymers inspired by quantum field theory. The proposed work aims to develop and optimize algorithms for simulations of coherent states models and apply those algorithms to fundamental studies of reversibly bonding, supramolecular polymers. Relationships will be explored between variables such as bonding equilibrium constants, stoichiometry and polymer architecture, and self-assembly behavior and thermodynamic properties. The unique structure of the coherent-states framework will enable a new force-matching scheme for systematic coarse-graining within FTS, applicable to both supramolecular and non-reactive polymer systems. Another component of the proposed research is to develop a workflow in which all-atom particle models are mapped to coarse-grained particle models using relative entropy minimization; the latter models of a form to allow analytical conversion to a fully-parameterized field theory. FTS can then be used to access mesoscale structure and thermodynamic properties directly connected to the underlying chemistry of the polymers. Broader impacts of the proposed research include engagement by the project personnel in graduate, undergraduate, and post-doctoral training in theoretical and computational polymer science. Theoretically-oriented students will be exposed to broader soft materials disciplines through a close coupling with experimental groups at the University of California, Santa Barbara (UCSB) in chemical engineering, materials, and chemistry. Knowledge gained under the proposed project will be leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercially relevant polymer formulations. The all-atom to FTS workflow targeted by the project has the potential to revolutionize in silico design of such formulations. All participants will contribute to the vibrant education and outreach programs of UCSB's Materials Research Science and Engineering Center.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.