Collaborative Research: Elastic and Viscoelastic Characterization and Modeling of Polymer Based Structures for Biological Applications

该奖项的研究目标是促进对软聚合物材料机械响应机制的科学理解，从而设计和建造用于生物医学应用的有效微/纳米结构和装置。将对软聚合物材料，即聚二甲基硅氧烷(PDMS)进行弹性和粘弹性表征和建模。这种聚合物材料将通过打孔测试和纳米压痕技术在不同的尺度上进行探测，从块状到微米/纳米级。计算结果将被应用到粘弹性有限元分析模型中。经过验证的模型最终将被用于根据测量的PDMS柱阵列的偏转来确定活细胞的机械力。为此，拟议的研究将需要在粘弹性材料的表征和为蜂窝力测量应用开发理论或数值粘弹性模型之间取得平衡。对聚二甲基硅氧烷粘弹性的深入研究将有助于在微米/纳米尺度上分析生物医学工业中常用的许多其他软聚合物材料。我们的愿景是通过开发新的理论模型和实验方法，扩大科学和工程界在小规模探索软聚合物材料的能力。这些表征技术和平台将允许科学家提出与生物医学研究相关的深刻和以前难以解决的问题，并获得分辨率足以在小范围内表征软材料的定量经验答案。该奖项将实施和传播一项教育和培训计划，通过软聚合物材料微/纳米表征的综合研究机会，在生物和纳米力学的边界上发展跨学科的思维模式。该项目将包括本科生和研究生研究，这两个机构的研究生教育，以及对高中生的推广。

The research objective of this award is to contribute to the scientific understanding of the mechanisms of the mechanical response of soft polymer materials so as to permit the design and construction of effective micro/nano structures and devices for biomedical applications. Elastic and viscoelastic characterization and modeling of a soft polymer material, namely polydimethylsiloxane (PDMS), will be performed. Such a polymer material will be probed at different scales from bulk down to the micro/nano levels using punch tests, and nanoindentation techniques. The results will be implemented into a viscoelastic finite element analysis model developed in tandem. The validated model will ultimately be utilized to determine the mechanical forces of living cells from the measured deflection of PDMS pillar arrays. To this end, the proposed research would entail a balance between characterization of the viscoelastic material and the development of a theoretical or numerical viscoelastic modeling for cellular force measurement applications. The scientific insights from the in-depth study of the viscoelasticity of PDMS will contribute to the analysis of many other soft polymer materials at micro/nano scales commonly used in biomedical industries. The vision is to expand the science and engineering community's capacity to probe soft polymer materials at small scales by developing both new theoretical models and experimental methodologies. These characterization techniques and platforms will allow scientists to ask profound and previously intractable questions related to biomedical research, and to obtain quantitative empirical answers with resolution sufficient to characterize the soft materials in small scales. This award will implement and disseminate an educational and training program that develops interdisciplinary modes of thought at the boundary of bio- and nano-mechanics through integrated research opportunities in micro/nano characterization of soft polymer materials. The project will incorporate undergraduate and graduate research, graduate education at both institutions and also outreach to high-school students.