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天然和工程机械驱动系统中起着重要作用，例如负责动物中快速和高功率大量运动的生物组织。弹性的模量提供了材料吸收和释放弹性应变能的能力，这取决于这些材料的强度和刚度之间的比率。通常，工程化的弹性模量极为困难，因为它需要不对称地增加强度和刚度，以抵抗其相互缩放的行为。作为另一种途径，该奖项支持基础研究，以阐明如何使用纳米颗粒来调整其聚合物复合材料的机械行为，以同时达到高强度和低刚度。这些知识将加速高强度的设计，但符合符合性的聚合物材料，以用于广泛的应用，例如轻质弹性储能设备，保护性涂料，柔性和可折叠的光电子和人造肌肉。因此，这项研究不仅会促进科学的进步，而且还可以促进民族健康，繁荣和福利。它还可以通过技术创新（例如飞机的轻量级吸收和保护系统。通过整合多个学科，该项目将在材料机制，聚合物科学，机械工程以及材料科学和工程方面培训各种各样的学生，以进行下一代劳动力发展。该项目的教育目标将通过课程开发，本科研究机会，高中生的夏季研究计划，K-12教师计划的研究经验和K-12外展计划来实现。将要做出特别的努力，使代表性不足的学生参与该项目。该项目的目的是检验以下假设：高强度和低刚度的组合归因于聚合物纳米复合材料的独特微观结构，该微结构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。目标1的目的是建立一个研究框架，该研究框架整合了多尺度分子建模和互补的纳米力学实验，以研究具有高强度和低刚度的聚合物纳米复合材料。它将用于阐明与聚合物基质的游离体积元素相比，纳米颗粒的大小如何影响聚合物纳米复合材料的机械行为。在AIM 2中，获得高强度和低刚度组合的基础力学原理将被推广，以指导一类新型聚合物纳米复合材料的探索。这些具有超高弹性能量存储能力的纳米复合材料可用于优质的机械保护，人造肌肉，软机器人和柔性电子设备。跨学科的努力将开辟有希望的途径，以定量了解异常的高强度和低僵硬行为，并提供机械洞察力，以了解一类新型的纳米复合材料的设计原理。该奖项反映了NSF的法定任务，并通过基金会的知识绩效和广泛的影响来评估NSF的法定任务，并被认为是值得通过评估来支持的。

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