RII Track-4: NSF: Understanding Microstructure Evolution in Stimuli-Responsive Yield-Stress Fluid-Assisted 3D Printing: Linking Microstructures to Macroscale Rheological Properties

RII Track-4：NSF：了解刺激响应屈服应力流体辅助 3D 打印中的微观结构演化：将微观结构与宏观流变特性联系起来

• 批准号: 2229004
• 负责人: Yifei Jin
• 金额: $ 23.18万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2229004&HistoricalAwards=false
• 关键词: RII; Track; NSF; Understanding; Microstructure

Recently, an innovative three-dimensional (3D) printing method has been proposed and developed to fabricate parts with arbitrary architectures. In this method, a 3D structure is freeform printed within a unique liquid support bath with desired properties that are controllable by either printing conditions or working environments. Although this method presents a better printing capability than many current 3D printing approaches, the working mechanisms of unique support bath materials are still elusive, which has hampered the further development of this 3D printing method. The project aims to investigate the microstructure changes of a representative thermosensitive support bath material at different temperatures and printing conditions. The achievements of this project can guide the design of more support baths as well as fundamentally explain the working mechanisms of printing within a support bath. The proposed research will have a profound societal impact by accelerating the development of 3D printing technology to enhance the manufacturing capability in the United States. In addition, the project will promote the education of students from K-12 to graduate in the State of Nevada through diverse activities, including hands-on K-12 lab activities, research module-involved curricula, and mentorship of students from underrepresented backgrounds at the University of Nevada, Reno. This Research Infrastructure Improvement Track-4 EPSCoR Research Fellows (RII Track-4) project would provide a fellowship to an Assistant professor and training for a graduate student at the University of Nevada Reno (UNR). Stimuli-responsive yield-stress fluids, developed on the basis of regular yield-stress materials, can change rheological properties/behaviors by responding to both applied shear stress and external stimuli. This dual-responsiveness makes stimuli-responsive yield-stress fluids promising for support bath-assisted 3D printing because a support bath material can be easily added during printing and removed after printing by applying external stimuli to achieve desired rheological properties, making it technically feasible to print 3D structures with arbitrary architectures. However, the interrelationships between microstructure evolution and macroscale rheology change of stimuli-responsive yield-stress fluids have so far remained elusive. Thus, the overarching goal of this project is to fundamentally understand the microstructure evolution of a representative stimuli-responsive yield-stress fluid—Pluronic F127-nanoclay nanocomposite—under different stress and temperature conditions through nanoscale material characterization, mathematical modeling, molecular dynamics simulation, and rheological testing. To achieve this goal, two integrated research objectives will be pursued: (1) characterize/establish static microstructure models in Pluronic F127-nanoclay nanocomposite via nanoscale material characterization techniques and mathematical modeling; and (2) explore temperature- and stress-induced microstructure evolutions via molecular dynamics simulation and rheological property testing. Completing the objectives will establish a paradigm for linking microstructures to macroscale rheological properties of support bath materials, promoting the development of more advanced stimuli-responsive yield-stress fluids for 3D printing applications in the future.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.

最近，人们提出并开发了一种创新的三维 (3D) 打印方法，用于制造具有任意架构的零件。在该方法中，3D 结构在独特的液体支撑浴中自由打印，具有可通过任一打印条件控制的所需特性。尽管这种方法比许多现有的3D打印方法具有更好的打印能力，但独特的支撑槽材料的工作机制仍然难以捉摸，这阻碍了这种3D打印方法的进一步发展。该项目旨在研究其微观结构。变化该项目的成果可以指导更多支持浴的设计，并从根本上解释支持浴内打印的工作机制。该研究将具有深远的社会意义。通过加速 3D 打印技术的发展，提高美国的制造能力，该项目还将通过各种活动，包括动手实践 K，促进内华达州 K-12 学生的教育。 -12 实验室活动、研究内华达大学里诺分校的模块课程和对来自代表性不足背景的学生的指导。该研究基础设施改进 Track-4 EPSCoR 研究人员 (RII Track-4) 项目将为助理教授提供奖学金，并为研究生提供培训。内华达大学里诺分校 (UNR) 的学生在常规屈服应力材料的基础上开发了刺激响应屈服应力流体，可以改变流变特性/行为。通过响应施加的剪切应力和外部刺激，这种双重响应性使得刺激响应屈服应力流体有望用于支撑浴辅助 3D 打印，因为支撑浴材料可以在打印过程中轻松添加，并在打印后通过施加外部刺激去除。以获得所需的流变特性，使得打印具有任意结构的 3D 结构在技术上是可行的。然而，微观结构演化和刺激响应屈服应力的宏观流变变化之间的相互关系。因此，该项目的首要目标是通过纳米级材料表征，从根本上了解代表性刺激响应屈服应力流体（Pluronic F127-纳米粘土纳米复合材料）在不同应力和温度条件下的微观结构演变，为了实现这一目标，将追求两个综合研究目标：（1）在 Pluronic 中表征/建立静态微观结构模型。 F127-纳米粘土纳米复合材料通过纳米级材料表征技术和数学建模；（2）通过分子动力学模拟和流变性能测试探索温度和应力引起的微观结构演化，完成目标将建立一个将微观结构与宏观流变性能联系起来的范例。支持浴材料，促进未来用于 3D 打印应用的更先进的刺激响应屈服应力流体的开发。该奖项是 NSF 的法定使命，并已被视为值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。

项目成果

3D printing‐based full‐scale human brain for diverse applications

基于 3D 打印的全尺寸人脑，适用于多种应用

• DOI: 10.1002/brx2.5
• 发表时间: 2023-04
• 期刊: Brain‐X
• 作者: Hua, Weijian;Zhang, Cheng;Raymond, Lily;Mitchell, Kellen;Wen, Lai;Yang, Ying;Zhao, Danyang;Liu, Shu;Jin, Yifei
• 通讯作者: Jin, Yifei