Unraveling Mechanics of High Strength and Low Stiffness in Polymer Nanocomposites through Integrated Molecular Modeling and Nanomechanical Experiments

通过集成分子建模和纳米力学实验揭示聚合物纳米复合材料的高强度和低刚度力学

• 批准号: 2316200
• 负责人: Ying Li
• 金额: $ 59.69万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2316200&HistoricalAwards=false
• 关键词: Unraveling; Mechanics; Strength; Low; Stiffness

The storage and release of elastic strain energy in materials, along with mechanical strength, play important roles in both natural and engineered mechanical actuation systems, such as biological tissues responsible for the fast and high-powered locomotions in animals. The modulus of resilience provides the measure of a material?s ability to absorb and release elastic strain energy, determined by the ratio between strength and stiffness of these materials. In general, engineering the modulus of resilience is extremely difficult because it requires asymmetrically increasing strength and stiffness against their mutual scaling behavior. As an alternative route, this award supports fundamental research to elucidate how nanoparticles can be used to tune mechanical behaviors of their polymer composites for simultaneously achieving high strength and low stiffness. This knowledge will accelerate the design of high strength, yet compliant polymeric materials for a broad range of applications, such as light-weight elastic energy storage devices, protective coatings, flexible and foldable optoelectronics, and artificial muscles. Thus, this research will not only promote the progress of science, but also advance the national health, prosperity and welfare. It can also help to secure national defense through technological innovations, e.g. light-weight energy absorption and protection systems for aircrafts. By integrating multiple disciplines, this project will train a diverse group of students in the areas of mechanics of materials, polymer science, mechanical engineering, and material science and engineering for next-generation workforce development. The educational objectives of the project will be realized through curriculum development, undergraduate research opportunities, summer research program for high school students, research experience for K-12 teachers program, and K-12 outreach program. Special efforts will be made to involve underrepresented students in this project. The objective of this project is to test the hypothesis that the combination of high strength and low stiffness is attributed to the unique microstructure of polymer nanocomposites that contains spherical nanoparticles weakly interacting with soft polymer matrix. To achieve this objective, the research plan consists of two major aims. The goal of Aim 1 is to establish a research framework integrating multiscale molecular modeling and complementary nanomechanical experiments for studying polymer nanocomposites with high strength and low stiffness. It will be used to elucidate how the size of nanoparticles, in comparison with free volume elements of the polymer matrix, can influence mechanical behaviors of polymer nanocomposites. In Aim 2, the underpinning mechanics principle of attaining the combination of high strength and low stiffness will be generalized to guide exploration of a novel class of polymer nanocomposites. These nanocomposites with ultra-high elastic energy storage capability can be used for superior mechanical protection, artificial muscles, soft robotics and flexible electronics. The interdisciplinary effort will open promising avenues for quantitatively understanding the anomalous high strength and low stiffness behaviors, and offer mechanistic insights into the design principles of a novel class of nanocomposites.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.

材料中弹性应变能的储存和释放，以及机械强度，在自然和工程机械驱动系统中都起着重要作用，例如负责动物快速和大功率运动的生物组织。弹性模量提供了对材料的测量。吸收和释放弹性应变能的能力，由这些材料的强度和刚度之比决定。一般来说，设计弹性模量是非常困难的，因为它需要不对称地增加强度和刚度，以对抗它们的相互缩放行为。作为一种替代途径，该奖项支持基础研究，以阐明如何使用纳米颗粒来调整聚合物复合材料的机械行为，同时实现高强度和低刚度。这一知识将加速高强度、柔性聚合物材料的设计，适用于广泛的应用，如轻质弹性储能装置、保护涂层、柔性和可折叠光电子产品和人造肌肉。因此，这项研究不仅将促进科学的进步，而且将促进国家的健康、繁荣和福利。它还可以通过技术创新，例如轻型能量吸收和飞机保护系统，帮助确保国防安全。通过整合多个学科，该项目将培养材料力学、聚合物科学、机械工程、材料科学与工程等领域的多元化学生，以培养下一代劳动力。该项目的教育目标将通过课程开发、本科生研究机会、高中生暑期研究计划、K-12教师研究经验计划和K-12外展计划来实现。我们将特别努力让代表性不足的学生参与这个项目。这个项目的目的是验证一个假设，即高强度和低刚度的结合是由于聚合物纳米复合材料的独特微观结构，其中包含球形纳米颗粒，与软聚合物基质弱相互作用。为了实现这一目标，研究计划包括两个主要目标。Aim 1的目标是建立一个多尺度分子建模和互补纳米力学实验相结合的研究框架，用于研究高强低刚度聚合物纳米复合材料。它将用于阐明纳米颗粒的大小，与聚合物基体的自由体积元素相比，如何影响聚合物纳米复合材料的力学行为。在目标2中，实现高强度和低刚度结合的基本力学原理将被推广，以指导探索一类新型聚合物纳米复合材料。这些具有超高弹性储能能力的纳米复合材料可用于卓越的机械保护、人造肌肉、软机器人和柔性电子产品。跨学科的努力将为定量理解异常的高强度和低刚度行为开辟有希望的途径，并为新型纳米复合材料的设计原则提供机理见解。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。

项目成果

Unraveling the ultrahigh modulus of resilience of Core-Shell SU-8 nanocomposite nanopillars fabricated by vapor-phase infiltration

揭示气相渗透制备的核壳SU-8纳米复合材料纳米柱的超高回弹性模量

• DOI: 10.1016/j.matdes.2023.111770
• 发表时间: 2023
• 期刊: Materials & Design
• 影响因子: 8.4
• 作者: Li, Zhongyuan;He, Jinlong;Subramanian, Ashwanth;Tiwale, Nikhil;Dusoe, Keith J.;Nam, Chang-Yong;Li, Ying;Lee, Seok-Woo
• 通讯作者: Lee, Seok-Woo