EAGER: Forced Assembly of Nanocomposite Structures using Polymer Crystallization

这一早期概念探索性研究补助金(AGER)奖提供资金，以评估在半结晶聚合物基质中组装纳米颗粒的可行性，分别使用聚合物结晶和晶体形态作为组装的驱动力和模板。具体地说，实验活动将集中在与使用一系列金纳米颗粒/聚氧化乙烯纳米复合材料的组装过程相关的三个关键问题上。首先，将使用结构和形态表征活动来确定纳米颗粒在聚合物晶体结构中的位置。纳米粒子在这种分层结构中的特定位置将影响材料的潜在应用。其次，模型纳米复合材料系统中使用的材料将允许牢固地检查组件相互作用对组装过程的影响，这将指导材料设计指南。第三，使用大范围速率的量热研究将被用来确定这种组装方法产生的结构是动力学捕获的还是处于准平衡状态。了解这种结构的热力学性质将对确定有利于纳米颗粒组装的加工策略具有重要意义。如果成功，本研究得到的预期形貌将具有功能和结构应用，直接应用于体相异质结有机光伏(OPV)，因为OPV器件的性能通常与结晶度和相分离的长度范围有关。最终，OPV效率和稳定性领域的进步将导致更昂贵的硅基光伏设备的广泛替代，使太阳能成为更负担得起的能源，并减少对化石燃料的依赖。除了OPV外，层次化纳米复合材料形态还可用于生物医学植入物，改善降解过程中的机械稳定性，以及用作具有细胞形态的结构材料。最后，研究结果将为理解半晶纳米复合材料的基本结晶行为提供有价值的新见解，这显然是颠覆性地推进这一领域所必需的。

This EArly-concept Grant for Exploratory Research (EAGER) award provides funding to evaluate the feasibility of assembling nanoparticles in semi-crystalline polymer matrices using polymer crystallization and crystal morphology as the driving force and template for assembly, respectively. Specifically, the experimental activities will focus on three key issues related to this assembly process using a series of gold nanoparticle/polyethylene oxide nanocomposites. First, structural and morphological characterization activities will be used to identify where nanoparticles locate in the polymer crystal structure. The specific locations preferred by the nanoparticles in this hierarchical structure will have impacts on the material's potential applications. Second, the materials used in the model nanocomposite system will allow the effects of component interactions on the assembly process to be robustly examined which will govern material design guidelines. And third, calorimetric studies using a wide range of rates will be used to determine if the structures resulting from this assembly method are kinetically-trapped or are in a quasi-equilibrium state. Understanding the structure's thermodynamic nature will have implications on determining processing strategies that favor nanoparticle assembly.If successful, the envisioned morphologies resulting from this research have functional and structural applications with direct application to bulk heterojunction organic photovoltaics (OPVs) since the performance of OPV devices is often tied to the degree of crystallinity and length scale of phase segregation achieved. Ultimately, advances in the areas of OPV efficiency and stability will lead to wide-spread replacement of the more expensive silicon-based photovoltaic devices, making solar energy a more affordable energy source and reducing dependence on fossil fuels. Beyond OPVs, hierarchical nanocomposite morphologies have applications as biomedical implants with improved mechanical stability during degradation as well as structural materials with cellular morphologies. Finally, the research results will provide valuable, new insight to understanding the fundamental crystallization behavior of semi-crystalline nanocomposites which is clearly needed to disruptively advance this area.