Collaborative Research: Exploring the Role of Ultra-Soft Inclusions in the Mechanics of Fibrous Materials

在自然界中，纤维材料如生物组织可以显示适应性行为。这些包括可调密度，刚度和渗透性，使它们能够承载机械载荷，对环境刺激做出反应并愈合伤口。这些行为是通过细胞和血小板等超软内含物及其与周围纤维网络的相互作用实现的，共同赋予其宿主材料专门的功能。在工程材料中模拟这种功能需要深入了解大变形下纤维网络中超软夹杂物的机械作用。该奖项支持有关超软夹杂物如何与纤维网络相互作用以及这些小规模相互作用如何影响主体材料的整体变形行为的基础研究。这项调查的结果不仅将为智能纺织品和可穿戴技术、伤口愈合、过滤膜和软机器人等领域的各种应用提供生物灵感、自适应材料的设计和制造的新见解，但它也将导致更好地理解生物组织中的生理和病理过程，这些过程是由细胞和细胞形式的超软内含物驱动的。像粒子一样，从而促进国家的健康，繁荣和福利。除了使更广泛的科学界受益外，这项工作还将通过新的跨学科课程模块，研究机会和跨机构访问计划来支持本科生和研究生教育。另一个更广泛的影响将是通过一个教育推广计划，旨在与德克萨斯州奥斯汀的国防部附属STEM青年计划合作，面向中学生，激励学生认识到从生物医学工程到土木和机械工程的许多工程原理的普遍性。纤维网络中的超软夹杂物在天然材料中普遍存在，并且尽管其尺寸小，但在总体机械性能中起关键作用。该奖项旨在了解高度可变形夹杂物与半柔性纤维网络的受控微观，局部和非局部相互作用如何导致工程材料中宏观尺度的涌现行为。重点是聚合物（纤维）主体材料在工程应用和自然界中的重要性。计算方法结合联合收割机表面丰富的数值工具占体积和表面粘附，elastocapillary效应，软固体梁接触现象，和数据驱动的均匀化，以预测聚合物颗粒复合材料的力学。关键是，该项目开发了一个可控的实验性微凝胶平台，以制备和研究具有高度可调机械性能的超软夹杂物。使用微凝胶材料平台的理论，计算以及微观和宏观尺度实验之间的迭代反馈循环是验证预测和通知模型开发的项目的核心。最后，该项目将提供一个定量的知识库和一个微凝胶合成平台，以证明通过控制超软夹杂物之间的非线性局部/非局部相互作用，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准。

In nature, fibrous materials such as biological tissues can display adaptive behaviors. These include tunable density, stiffness, and permeability, which allow them to carry mechanical loads, respond to environmental stimuli, and heal wounds. These behaviors are achieved through ultra-soft inclusions like cells and platelets, and their interactions with the surrounding fibrous network, collectively lending their host materials specialized functions. Mimicking such functions in engineered materials requires a deep understanding of the mechanical role of ultra-soft inclusions in fiber networks at large deformations. This award supports fundamental research on how ultra-soft inclusions interact with a network of fibers and how these small-scale interactions affect the overall deformation behavior of the host material. The findings from this investigation will not only provide new insights into the design and fabrication of bio-inspired, adaptive materials for diverse applications in smart textiles and wearable technology, wound healing, filtration membranes, and soft robotics, but it will also lead to a better understanding of physiological and pathological processes in biological tissues that are driven by ultra-soft inclusions in the form of cells and cell-like particles, consequently advancing the national health, prosperity, and welfare. In addition to benefitting the broader scientific community, this work will also support undergraduate and graduate education through new, interdisciplinary class modules, research opportunities, and a trans-institutional visitation program. An additional broader impact will be through an education outreach program aimed at middle school students in collaboration with a Department of Defense-affiliated STEM youth program in Austin, TX, inspiring the students to recognize the universality of many engineering principles spanning from biomedical engineering to civil and mechanical engineering.Micron-sized, ultra-soft inclusions in fiber networks are ubiquitous in natural materials and play a critical role in the overall mechanical properties despite their small size. This award aims to understand how controlled microscale, local and non-local interactions of highly deformable inclusions with semi-flexible fiber networks lead to emergent behaviors at macroscales in engineered materials. The focus is on polymeric (fibrous) host materials for their importance in both engineering applications and nature. Computational approaches combine surface-enriched numerical tools accounting for bulk and surface adhesion, elastocapillary effects, soft solid-beam contact phenomena, and data-driven homogenization to predict the mechanics of polymer-particle composites. Critically, this project develops a controllable, experimental microgel platform to make and study ultra-soft inclusions with highly tunable mechanical properties. An iterative feedback loop between theory, computations, and micro- and macroscale experiments using the microgel material platform is central to the project for validating predictions and informing the model development. Ultimately, this project will provide a quantitative knowledge base and a microgel synthesis platform to demonstrate that the material design space of composites with ultra-soft inclusions can be precisely tuned through control of the nonlinear local/nonlocal interactions between ultra-soft inclusions and fibrous networks.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.