CAREER: Nanoscale Resolution of Near-Interface Crystallization in Multicomponent Semicrystalline Polymeric Materials

职业：多组分半晶聚合物材料中近界面结晶的纳米级分辨率

• 批准号: 2338613
• 负责人: Kailong Jin
• 金额: $ 64万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-09-01 至 2029-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338613&HistoricalAwards=false
• 关键词: CAREER; Nanoscale; Resolution; Near; Interface

PART 1: NON-TECHNICAL SUMMARYSemicrystalline polymers comprise ~70% of all synthetic plastics, and they are pervasive in daily life in packaging, transportation, and high-technology applications like microelectronics. Semicrystalline polymers are often used in the form of multicomponent polymeric materials, e.g., multilayer polyethylene/poly(ethylene terephthalate) films for packaging and carbon fiber-reinforced composites for transportation. A key feature of these multicomponent materials is the presence of a large quantity of polymer/polymer or polymer/filler interfaces. Understanding the effects of these interfaces on polymer crystallization is essential to the predictive design of multicomponent materials with desired crystalline structures and properties. Unfortunately, such a fundamental understanding is lacking. This project will work toward closing the fundamental knowledge gap in interfacial effects and polymer crystallization, using a new fluorescence technique with a nanoscale spatial resolution. The fundamental knowledge gained from this research will advance the development of new multicomponent materials with optimized crystalline structures and properties, which can contribute to a broad range of applications such as food packaging and biomedical devices. This project will provide an integrated research and educational experience for graduate students, undergraduate students, and high-school students, including members of underserved groups. The principal investigator and students will also develop education-oriented online videos and hands-on demonstrations to engage the general public and attract K-12 students into STEM fields. PART 2: TECHNICAL SUMMARYThis project’s research goal is to advance fundamental understanding of the interfacial effects on crystallization in multicomponent semicrystalline polymers, using a new fluorescence technique with a nanoscale spatial resolution. The principal investigator (PI) plans to achieve this goal by strategically placing trace amounts of “reporter” (i.e., crystal-sensing) fluorescent dye labels at controlled distances from interfaces to elicit fluorescence-based information about local crystallization and thus interfacial effects. Towards this goal, the PI and students will pursue three research thrusts: (1) Understand the role of fluorescence as a crystallization-sensing mechanism by selectively placing the dyes in rigid vs. mobile amorphous fraction regions to deconvolute their contributions to the overall fluorescence; (2) Study near-interface crystallization by location-specific fluorescence and complementary methods such as grazing-incidence X-ray scattering; (3) Unveil polymer/polymer and polymer/substrate interfacial effects on crystallization and their perturbation length-scale. Material studies will focus on degradable poly(L-lactic acid) (PLLA) as a model semicrystalline polymer to advance the design of new PLLA-based multicomponent materials with desired structures/properties and improved sustainability, including multilayer films, composites, blends, and block copolymers. The education/outreach plan will broaden the reach and benefits of this CAREER research at multiple levels: (1) The PI and students will reach out to the general public through online educational videos on semicrystalline polymers; (2) The PI will develop a new lab module on plastic packaging and leverage the existing research programs at ASU to train graduate students, undergraduate students, and high-school students on polymer synthesis and characterization; (3) The PI and students will develop hands-on demonstrations at ASU Open Door to stimulate local K-12 students’ interest in polymers and STEM careers..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.

第一部分：非技术概述半结晶聚合物占所有合成塑料的约70%，在包装、运输和微电子等高科技应用中广泛存在于日常生活中。半结晶聚合物通常以多组分聚合物材料的形式使用，用于包装的多层聚乙烯/聚对苯二甲酸乙二醇酯薄膜和用于运输的碳纤维增强复合材料。这些多组分材料的关键特征是存在大量的聚合物/聚合物或聚合物/填料界面。了解这些界面对聚合物结晶的影响对于预测设计具有所需晶体结构和性能的多组分材料至关重要。不幸的是，缺乏这样一种基本的理解。该项目将致力于缩小界面效应和聚合物结晶的基本知识差距，使用具有纳米级空间分辨率的新荧光技术。从这项研究中获得的基础知识将促进具有优化晶体结构和性能的新型多组分材料的开发，这有助于广泛的应用，如食品包装和生物医学设备。该项目将为研究生，本科生和高中生，包括服务不足群体的成员提供综合研究和教育经验。首席研究员和学生还将开发以教育为导向的在线视频和动手演示，以吸引公众参与，并吸引K-12学生进入STEM领域。 第二部分：本项目的研究目标是利用具有纳米级空间分辨率的新荧光技术，推进对多组分半结晶聚合物中结晶界面效应的基本理解。主要研究者（PI）计划通过战略性地放置痕量的“报告者”（即，晶体感测）荧光染料标记，以引出关于局部结晶和因此的界面效应的基于荧光的信息。为达致这个目标，研究者和学生将进行三项研究：（1）透过选择性地将染料置于刚性或移动的非晶部分区域，以解卷积它们对整体荧光的贡献，从而了解荧光作为结晶感应机制的作用;（2）通过位置特异性荧光和互补方法如掠入射X射线散射研究近界面结晶;（3）揭示了聚合物/聚合物和聚合物/基体界面对结晶的影响及其扰动长度尺度。材料研究将集中在可降解聚（L-乳酸）（PLLA）作为模型半结晶聚合物，以推进新的PLLA基多组分材料的设计，具有所需的结构/性能和改善的可持续性，包括多层膜，复合材料，共混物和嵌段共聚物。教育/推广计划将在多个层面上扩大这项CAREER研究的范围和利益：（1）PI和学生将通过半结晶聚合物的在线教育视频与公众接触;（2）PI将开发一个新的塑料包装实验室模块，并利用ASU现有的研究项目来培养研究生，本科生，（3）PI和学生将在ASU Open Door开发动手演示，以激发当地K-12学生对聚合物和STEM职业的兴趣。该奖项反映了NSF的法定使命，并被认为是值得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的支持。