Chemo-Mechanical Coupling in the Erosion of Degradable Polymers

这项拨款将重点研究受机械力和反应性环境共同作用的可降解聚合物的侵蚀。近年来，可降解聚合物因其在减少聚合物浪费和多种生物医学应用方面的巨大潜力而受到越来越多的关注。在实际应用中，可降解聚合物在降解过程中往往承受机械载荷。因此，机械力必然会影响可降解聚合物的侵蚀过程，降解过程也会逐渐改变聚合物的力学性能。尽管它在应用中很重要，但迄今为止对可降解聚合物力学和化学之间相互作用的理解非常有限。本研究计划旨在利用实验和理论方法来研究在复杂的化学和机械作用下可降解聚合物腐蚀的基础科学。这项研究将有助于全球开发新的可降解聚合物以减少聚合物浪费，并不断探索新的生物降解聚合物用于新的生物医学应用。该项目的影响将通过综合教育和外展计划进一步扩大，包括跨学科教育和研究生和本科生的培训机会，为圣地亚哥地区的弱势群体，第一代高中生和大学生提供实习机会，以及为全国7-10年级的学生提供STEM计划。研究的具体目标是发现可降解聚合物在腐蚀过程中的化学-力学耦合效应。本项目的研究目标包括：(a)建立一个新的理论框架来预测可降解聚合物在侵蚀过程中的时间依赖性行为；(b)建立了预测可降解聚合物应力腐蚀开裂的新模型；(c)揭示施加的应力如何影响可降解聚合物的侵蚀模式（即表面侵蚀与整体侵蚀）；(d)揭示了外加应力对表面侵蚀过程中可降解聚合物的形态变化、诱导时间和前沿传播速度的影响。该项目将为可降解聚合物的化学和力学之间的相互作用创造新的知识，从而为定量预测可降解聚合物的化学-力学行为和设计用于各种应用的新型可降解聚合物奠定基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will focus on investigating the erosion of degradable polymers subject to the concurrent actions of mechanical force and a reactive environment. Degradable polymers have recently attracted increasing attention for their great potential of reducing polymer waste and diverse biomedical applications. In practice, degradable polymers often carry mechanical load during their degradation. As a result, the mechanical force will inevitably influence the erosion process of degradable polymers, and the degradation process will also gradually change the polymer's mechanical properties. Despite its importance in applications, the understanding of the interplay between mechanics and chemistry in degradable polymers has so far been extremely limited. This research program aims to use both experimental and theoretical approaches to investigate the fundamental science governing the erosion of degradable polymers under complex chemical and mechanical actions. This research will contribute to the intense global effort to develop new degradable polymers for reducing polymer waste as well as the incessant exploration of new biodegradable polymers for novel biomedical applications. The impact of the project will be further broadened via the integrated education and outreach programs including interdisciplinary education and training opportunities to graduate and undergraduate students, internships for disadvantaged, first generation high school and college students in the greater San Diego area and a STEM program for academically-advanced 7-10th grade students from nationwide.The specific goal of the research is to discover the chemo-mechanical coupling effects in degradable polymers during its erosion. The research objectives of this project include: (a) establishing a new theoretical framework for predicting the time-dependent behaviors of degradable polymers during the erosion process;(b) creating a new model for predicting stress corrosion cracking in degradable polymers;(c) uncovering how applied stresses may affect the erosion modes of a degradable polymer (i.e., surface erosion vs. bulk erosion);(d)revealing the effects of applied stress on the morphological change, induction time and front propagation speed of degradable polymers during the surface erosion process. The project will create new knowledge of the interplay between chemistry and mechanics in degradable polymers, thereby laying the foundation for quantitatively predicting the chemo-mechanical behaviors of degradable polymers and designing new degradable polymers for diverse applications.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.