Fabrication, Nanomechanical Properties, and Surface Functionality of Polymer Nanocomposites

聚合物纳米复合材料的制备、纳米机械性能和表面功能

• 批准号: 0201551
• 负责人: Kyriakos Komvopoulos
• 金额: $ 36万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0201551&HistoricalAwards=false
• 关键词: Fabrication; Nanomechanical; Properties; Surface; Functionality

Advances in nanomanufacturing greatly depend on basic understanding of how to control building blocks of materials. Polymers have attracted significant attention in recent years, largely due to the rapid emergence of biotechnology and microelectronics. However, basic knowledge of the surface properties of polymers, often affecting component functionality more profoundly than bulk properties, and in-depth understanding of underlying deformation mechanisms at the nanoscale is very sparse. The central theme of this research is to bridge this gap by performing nanomechanical testing and surface chemical analysis on micrometer-thick polymer specimens manufactured by spin casting. The model polymers selected for study are polyurethane elastomers, comprising two insoluble monomers of relatively low and high glass transition temperatures, referred to as soft and hard segments, respectively. The principal objective is to examine the surface nanomechanical properties and adhesion (friction) characteristics in terms of polymer composition, contact load, elongation strain, and time under fixed elongation. The surface texture and material properties of pre-strained nanocomposite specimens will by studied by atomic force and surface force microscopy, while the surface chemical behavior at different strain levels and time under constant elongation will be analyzed by sum frequency generation vibrational spectroscopy. The information derived from this research will enhable enginnering of chemomechanical behavior of polymer nanocomposites, with direct implications to the manufacturing of nanodevices exhibiting tailor-made properties and multi-arrays/bio-implants possessing either hydrophilic or hydrophobic chemical behaviors, depending on the surface composition and applied strain. In addition, this project will provide the opportunity to two graduate students to become invovled with interdisciplinary research dealing with polymer mechanical property evaluation and chemical analysis at submicron scales using surface-specific state-of-the-art microsocpy and spectroscopy techniques. Such combination of surface-sensitive instrumentation is one of the strengths of this proposal. Results from this research will be incroporated in the content of a graduate course taught annualy by the PI, which currently addreses only bulk polymer behavior. This initiative will also enable the development of collaborations with industry involved with polymer biomaterials research and development, thereby increasing the application range of the obtained basic knowledge regarding the evolution of surface mechanical properties and chemical characteristics of strecthed polymer nanocomposites.

纳米制造的进步很大程度上取决于对如何控制材料构建块的基本理解。近年来，聚合物引起了人们的极大关注，这主要是由于生物技术和微电子技术的迅速兴起。然而，聚合物的表面性质的基本知识，往往影响组件的功能更深刻地比散装性能，并在纳米级的基本变形机制的深入了解是非常稀疏。本研究的中心主题是通过对旋转铸造制造的微米厚聚合物样品进行纳米力学测试和表面化学分析来弥合这一差距。选择用于研究的模型聚合物是聚氨酯弹性体，其包含两种玻璃化转变温度相对较低和较高的不溶性单体，分别称为软链段和硬链段。主要目的是研究表面纳米机械性能和粘附（摩擦）特性的聚合物组合物，接触载荷，伸长应变，和固定伸长率下的时间。利用原子力显微镜和表面力显微镜研究了预应变纳米复合材料试样的表面织构和材料性能，并利用和频振动光谱分析了在恒定延伸率下不同应变水平和时间下的表面化学行为。从这项研究中获得的信息将增强聚合物纳米复合材料的化学机械行为的工程化，直接影响到纳米器件的制造，这些纳米器件表现出定制的特性和具有亲水或疏水化学行为的多阵列/生物植入物，这取决于表面组成和施加的应变。此外，该项目将为两名研究生提供机会，使他们能够参与跨学科研究，利用表面特定的最先进的显微镜和光谱技术，在亚微米尺度上进行聚合物机械性能评估和化学分析。这种表面敏感仪器的组合是该建议的优点之一。这项研究的结果将被纳入PI每年教授的研究生课程的内容中，该课程目前仅涉及本体聚合物行为。这一举措还将促进与涉及聚合物生物材料研究和开发的行业的合作，从而增加所获得的关于拉伸聚合物纳米复合材料的表面机械性能和化学特性演变的基础知识的应用范围。