Microstructure and Properties of Inhomogeneous Polyatomic Mixtures from Density Functional Theory

从密度泛函理论研究非均匀多原子混合物的微观结构和性能

• 批准号: 0756166
• 负责人: Walter Chapman
• 金额: $ 30万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2012-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0756166&HistoricalAwards=false
• 关键词: Microstructure; Properties; Inhomogeneous; Polyatomic; Mixtures

CBET-0756166ChapmanMany modern applications of macromolecular fluids take advantage of their novel microstructure and phase behavior. The challenge in modeling nano-structured fluids lies in understanding the new physics that emerges from finite-size effects, varying dimensionality, surface forces and interplay of multiple length and time scales. The introduction of external surface forces and the competition between fluid substrate and fluid-fluid interactions lead to interesting surface driven phase changes not seen in bulk systems [9]. Intellectual Merit: The project focuses on the to development of a novel molecular theory for multi-scale modeling of complex fluid assemblies and to apply the theory to several critical problems in nano-structured media. The work builds on the PIs new density functional theory (DFT) that has shown an unprecedented combination of accuracy and simplicity in predicting the structure of inhomogeneous polyatomic mixtures [29,30]. Predictions of the DFT are in excellent agreement with molecular simulation results for phenomena such as polymer depletion, enhancement and surface induced segregation key elements in polymer-colloid systems and in coatings of polymer blends. Further, the DFT has similar simplicity and computational speed to an atomic density functional theory. We propose to incorporate multiple molecular association sites, chain stiffness, and hydrophilic and hydrophobic surfaces in the theory. The approach will be validated with molecular simulation results and compared with experiment for interfacial properties and structure of copolymer, surfactant, and tethered polymer systems. Broader Impact: The immense potential of the DFT has led to an ongoing collaboration with Sandia National Laboratories (SNL) to incorporate our DFT within their massively parallel DFT solver package ? TRAMONTO. With its existing capabilities, TRAMONTO can address life-scale systems such as colloids and electrolytes in a range of 2D/3D geometries. Integrating the PIs polyatomic DFT within this platform dramatically expands the potential scope of the package to such systems as self-assembly in polymer-colloid polymer-nanoparticle systems, block copolymer films and blends, surfactant or lipid systems exhibiting micellar or bilayer structures, and polyelectrolytes. When the final version is released to the public, it is anticipated that these computational tools will have high impact on nanoscience and design of nanosystems by allowing exhaustive analysis of design or phase space (needed for design of experiments) at a moderate expense. Dow Chemical has significant interest in applying the theory to model microstructure and interfacial properties of copolymer solutions, blends, and surfactants. Letters of collaboration from Sandia and Dow are attached with direct and in-kind funding from Dow. Of further impact will be education of a graduate student, post-doc, and undergraduate students participating in the project. These students will make presentations to companies that have participated in our Consortium on Complex Fluids and present research results at international conferences. The graduate student benefited from a summer internship offered by Dow. In addition to incorporating new theory in courses at Rice, the project will develop an educational module (book chapter) of the theory for web distribution using the internationally recognized Connexions environment (cnx.rice.edu).

CBET-0756166Chapman高分子流体的许多现代应用都利用了其新颖的微观结构和相行为。纳米结构流体建模的挑战在于理解有限尺寸效应、变化维度、表面力以及多个长度和时间尺度的相互作用所产生的新物理现象。外表面力的引入以及流体基质和流体-流体相互作用之间的竞争导致了在本体系统中未见的有趣的表面驱动相变[9]。智力优势：该项目专注于开发一种用于复杂流体组件多尺度建模的新型分子理论，并将该理论应用于纳米结构介质中的几个关键问题。这项工作建立在 PI 的新密度泛函理论 (DFT) 的基础上，该理论在预测非均质多原子混合物的结构方面显示出前所未有的准确性和简单性结合 [29,30]。 DFT 的预测与聚合物胶体系统和聚合物共混物涂层中聚合物耗尽、增强和表面诱导偏析等现象的分子模拟结果非常一致。此外，DFT 具有与原子密度泛函理论类似的简单性和计算速度。我们建议在理论中纳入多个分子缔合位点、链刚度以及亲水和疏水表面。该方法将通过分子模拟结果进行验证，并与共聚物、表面活性剂和系链聚合物系统的界面性质和结构的实验进行比较。更广泛的影响：DFT 的巨大潜力促使我们与桑迪亚国家实验室 (SNL) 持续合作，将我们的 DFT 纳入其大规模并行 DFT 求解器包中？特拉蒙托。凭借其现有功能，TRAMONTO 可以处理各种 2D/3D 几何形状的胶体和电解质等生命尺度系统。将 PI 多原子 DFT 集成到该平台中，极大地扩展了该套件的潜在范围，例如聚合物-胶体聚合物-纳米粒子系统中的自组装、嵌段共聚物薄膜和共混物、表现出胶束或双层结构的表面活性剂或脂质系统以及聚电解质。当最终版本向公众发布时，预计这些计算工具将以适度的费用对设计或相空间（实验设计所需）进行详尽的分析，从而对纳米科学和纳米系统的设计产生重大影响。陶氏化学非常有兴趣应用该理论来模拟共聚物溶液、共混物和表面活性剂的微观结构和界面特性。桑迪亚和陶氏化学公司的合作函附有陶氏化学公司的直接和实物资助。进一步影响的将是参与该项目的研究生、博士后和本科生的教育。这些学生将向参加我们复杂流体联盟的公司进行演讲，并在国际会议上展示研究成果。该研究生受益于陶氏化学公司提供的暑期实习机会。除了将新理论纳入莱斯大学的课程之外，该项目还将使用国际公认的 Connexions 环境 (cnx.rice.edu) 开发网络分发理论的教育模块（书籍章节）。