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

该学院早期职业发展（Career）项目将研究微结构软材料（如共轭聚合物）的机械现象，通过设计实现可拉伸性，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本材料，用于各种电子材料系统和传感装置，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。然而，共轭聚合物是不可拉伸的。虽然通常是柔性的，但它们的拉伸性被限制在几个百分点以内。在大变形时，裂纹会降低电子设备的性能。这一弱点限制了它们在需要大拉伸性的工业应用和需要完全灵活性的新应用中的使用。社会将受益于通过力学驱动的模拟来预测材料性能的新方法，用于柔性混合电子。该奖项将为高中到研究生在微建筑材料设计和宏观建筑可持续系统方面创造科学、技术、工程和数学方面的机会，并将通过减少第一代大学生攻读工程学位的障碍，对多样性产生影响。目前，还没有理论能够可靠地预测聚合物共混物在不稳定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技术，可以提高软材料系统的拉伸性。也没有理论来预测所得到的共轭/非晶聚合物共混材料的失效行为，以及这些材料在柔性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的广泛范围导致模拟只能以定性的方式捕捉实验观察到的现象。本项目旨在通过综合理论、计算和实验方法来缩小这一差距。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，使这个奖项显得尤为及时。这项研究将有助于开发计算尺度的桥接技术，以定量地预测不同聚合物、溶剂和衬底性质、混合比例或蒸发速率对聚合物共混物的诱导不稳定性、共混物形态、纳米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.