Local Polymer Interfacial Mechanics: Effect of Topological and Chemical NanoPatterning

该补助金将回答有关聚合物的动态力学性能的开放性问题，这些聚合物靠近具有不同几何限制和化学功能的表面（在数十至数百纳米内）。表面附近的小尺度局部聚合物行为不仅局部地而且在体尺度上显著地影响薄膜中的聚合物、微电子学中的纳米级结构、药物递送装置和纳米复合材料的机械行为。对这些局部界面性质的机械理解和控制是设计和制造经济和技术上重要的产品和工艺的关键因素，从飞机结构复合材料部件到零排放车辆电源。该项目将使用小规模的实验方法结合计算建模，以深入了解局部聚合物界面力学，以推进最佳材料设计。因此，该项目将为博士后、研究生和本科生等不同群体提供跨学科培训，通过参与当地K-12科学活动，实现社区外联，本研究的目标是通过应用先进的原子力显微镜纳米压痕实验，结合有针对性的，新型聚合物-基底界面模型系统的有限元分析模拟。由于在各种应用中的聚合物的一般复杂的配置，模型基板系统将被设计为研究多体化合物的影响所产生的同时相互作用的本地聚合物域与多个功能接口。一套包含拓扑和化学图案的聚合物-基底界面样品将使用光刻技术制造。局部弹性模量梯度将映射在高分辨率使用耦合的实验和模拟的方法，使数据分析将能够反卷积复杂的实验文物。先进的动态原子力显微镜模式也将用于评估聚合物动力学的局部变化。该模型系统是作为在实际材料应用中的受限聚合物的良好定义的模拟物制造的，并通过利用组合方法提供了一种提高表征效率的途径。为了加速数据收集和分析，基质样品将被设计为使得可以在单个样品中探测许多相间条件。总的来说，这些研究将为受限聚合物的性质和影响提供关键的基本见解，并使使用聚合物和复合材料的多功能和坚固系统的合理设计成为可能。该奖项反映了NSF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 answer open questions about the dynamic-mechanical properties of polymers in close proximity to surfaces (within tens to hundreds of nanometers) with varying geometric confinement and chemical functionalities. Small scale, local polymer behavior near surfaces dramatically affects the mechanical behavior of polymers in thin films, nanoscale structures in microelectronics, drug delivery devices, and nanocomposites, not only locally, but also at the bulk scale. Mechanistic understanding of, and control over, these local interphase properties is a crucial factor for the design and manufacture of economically and technologically important products and processes, from aircraft structural composite components to zero-emission vehicle power sources. This project will use small scale experimental methods in conjunction with computational modeling to develop a deep understanding of the local polymer interfacial mechanics to advance optimal material design. As such, the project will provide cross-disciplinary training to a diverse group of postdoctoral, graduate, and undergraduate trainees, enable community outreach by engaging with local K-12 science events, and contribute to digital data curation and distribution platforms.The goal of this research is to characterize the local mechanical gradients in confined polymers by applying advanced atomic force microscopy nanoindentation experiments coupled with targeted finite element analysis simulations to novel polymer-substrate interface model systems. Due to the generally complex configuration of polymers in various applications, model substrate systems will be designed to study multi-body compound effects arising from simultaneous interactions of local polymer domains with multiple functional interfaces. A suite of polymer-substrate interface samples containing topological and chemical patterns will be fabricated using lithography techniques. Local elastic modulus gradients will be mapped at high resolution using a coupled experimental and simulated approach such that data analysis will enable deconvolution of complex experimental artifacts. Advanced dynamic atomic force microscopy modes will also be employed to assess local changes in polymer dynamics. The model systems are fabricated as well-defined mimics of confined polymers in actual materials applications and provide an avenue for increased characterization efficiency by leveraging a combinatorial approach. To accelerate data collection and analysis, substrate samples will be designed such that many interphase conditions can be probed within one single sample. Overall, the investigations will provide key fundamental insights into the nature and impact of confined polymers and enable the rational design of multifunctional and robust systems using polymers and composites.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.