Collaborative Research: Measurements of Yield Strength and Local Viscoelastic Properties Using Nanoparticle Embedment Methods

合作研究：使用纳米颗粒嵌入方法测量屈服强度和局部粘弹性

• 批准号: 1132174
• 负责人: Hongbing Lu
• 金额: $ 11.89万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1132174&HistoricalAwards=false
• 关键词: Collaborative; Research; Measurements; Yield; Strength

The proposed work expands a novel nanosphere embedment experiment to the measure of the yield behavior of surfaces. The method also promises a novel, high spatial resolution method to map the surface mechanical/viscoelastic properties of polymeric and composite materials. The work builds on CMMI supported work in which it was found that nanoparticles smaller than a certain size sink into the surface and become fully engulfed by the polymer. Analysis suggests that the nanoparticles are fully engulfed only when the yield strength of the polymer surface is exceeded, which opens a route to measure the surface yield strength, as well as other properties at depths on the order of 20 nm. If successful, it will also lead to a technique to provide a surface property map of mechanical, including modulus, yield strength, and viscoelastic properties of polymer surfaces using embedment of a monolayer of clustered nanoparticles. The work also involves numerical analysis of the embedment process to include appropriate elastic-plastic, viscoplastic or viscoelastic constitutive models to extract nonlinear material properties. By its interdisciplinary nature, the project provides a rare training opportunity for students in both chemical engineering and mechanical engineering to step into research in the thermo-mechanical behavior of polymers at the nanoscale. In addition, it is a collaborative project in which the graduate students will have the opportunity to interact with students from another institution and work with them. Part of the work in this project will be divided into smaller projects for use in term projects in courses such as viscoelasticity and polymer physics offered by the PIs in this project. All significant results will be published in journals to disseminate the findings. It is anticipated that the graduate students working on the project will present their findings at national/international conferences.

所提出的工作将一种新颖的纳米球嵌入实验扩展到了表面屈服行为的测量。该方法还有望提供一种新颖的高空间分辨率方法来绘制聚合物和复合材料的表面机械/粘弹性特性。这项工作建立在 CMMI 支持的工作基础上，其中发现小于一定尺寸的纳米粒子沉入表面并被聚合物完全吞没。分析表明，只有当超过聚合物表面的屈服强度时，纳米颗粒才会被完全吞噬，这开辟了测量表面屈服强度以及 20 nm 左右深度的其他性能的途径。 如果成功，它还将催生一种技术，通过嵌入单层簇状纳米颗粒来提供聚合物表面的机械性能图，包括模量、屈服强度和粘弹性性能。 这项工作还涉及嵌入过程的数值分析，包括适当的弹塑性、粘塑性或粘弹性本构模型，以提取非线性材料特性。由于其跨学科性质，该项目为化学工程和机械工程专业的学生提供了难得的培训机会，让他们能够深入研究纳米尺度聚合物的热机械行为。此外，这是一个合作项目，研究生将有机会与其他机构的学生互动并与他们一起工作。 该项目的部分工作将被分成较小的项目，用于该项目中的 PI 提供的粘弹性和聚合物物理等课程的学期项目。所有重要的结果都将发表在期刊上以传播研究结果。预计从事该项目的研究生将在国内/国际会议上展示他们的发现。