CAREER: Stretchability by Design - Understanding Mechanical Phenomena in Microarchitectured Soft Material Systems

该学院早期职业发展(CALEAR)课程将研究微体系结构软材料(如共轭聚合物)中的机械现象，以实现设计上的可伸缩性，从而在大应力下稳定设备性能。共轭聚合物被认为是有机半导体的基础材料，用于能源、医疗保健、生物医学、民用、机械、航空航天和化学工程等领域的各种电子材料系统和传感设备。然而，共轭聚合物是不可拉伸的。虽然总体上是灵活的，但它们的延伸性被限制在几个百分点以内。在大变形时，裂纹可能会降低电子设备的性能。这一弱点限制了它们在需要较大可伸缩性的工业应用和需要完全灵活性的新应用中的使用。社会将受益于通过用于柔性混合电子设备的力学驱动的模拟来预测材料特性的新方法。该奖项将为高中研究生创造微结构材料设计和宏观结构可持续系统的科学、技术、工程和数学机会，并将通过降低第一代大学生攻读工程学学位的障碍来影响多样性。目前，还没有理论可靠地预测聚合物共混物在不稳定诱导相分离过程中产生的所有复杂相互作用和非平衡机制，这是一种很有前途的提高软材料系统延伸性的技术。也没有一种理论来预测产生的共轭/非晶态聚合物共混材料的失效行为，以及这些材料在灵活的混合电子应用中必须承受的大变形。这些机制的长度和时间尺度范围很广，导致模拟只能定性地捕捉实验观察到的现象。该项目旨在通过理论、计算和实验的综合方法来弥合这一差距。理论力学、高性能计算资源、实验测试和可视化技术的惊人进步使这一奖项特别及时。这项研究将有助于开发计算规模桥接技术，以定量预测不同的聚合物、溶剂和基材性质、共混比或挥发速率对聚合物共混物中诱导不稳定性、共混形态、纳米受限聚合物性质和失效机制的影响。

This Faculty Early Career Development (CAREER) program will investigate mechanical phenomena in microarchitectured soft materials such as conjugated polymers to achieve stretchability by design and thereby stable device performance under large stresses. Conjugated polymers are considered as the basic material for organic semiconductors, which are used for various electronic material systems and sensing devices for applications in energy, healthcare, biomedical, civil, mechanical, aerospace, and chemical engineering. However, conjugated polymers are not stretchable. While generally flexible, their stretchability is restricted up to a few percent. At large deformations, cracks can deteriorate electronic device performance. This weakness limits their use in industrial applications that require large stretchability and new applications demanding complete flexibility. Society will benefit from new methods to predict material properties via mechanics-driven simulations for use in flexible hybrid electronics. The award will create science, technology, engineering, and mathematics opportunities for high school to graduate students in microarchitectured material design and macroarchitectured sustainable systems, and will impact on diversity by reducing barriers of first generation college students to pursue an engineering degree.Currently, no theory reliably predicts all the complex interactions and non-equilibrium mechanisms arising during instability-induced phase separation of polymer blends, being a promising technique to increase stretchability in soft material systems. Nor is there a theory to predict failure behavior of the resulting conjugated/amorphous polymer blend material and the large deformation those materials must withstand in flexible hybrid electronics applications. The wide range of length and time scales of those mechanisms results in simulations merely able to capture experimentally observed phenomena in a qualitative way. This project aims to close this gap by an integrated theoretical, computational, and experimental approach. The astonishing advancements of theoretical mechanics, high-performance computational resources, and experimental testing and visualization techniques, make this award particularly timely. This research will contribute to developing computational scale bridging techniques to predict, quantitatively, the effect of varying polymer, solvent, and substrate properties, blend ratios, or evaporation rates on induced instabilities, blend morphologies, nanoconfined polymer properties, and failure mechanisms in polymer blends.