LEAPS-MPS: Harnessing materials from nature: from biomaterials to metal oxides

第一部分：非技术性总结人们普遍认为，自从地球上出现第一批动植物以来，大自然一直在完善其材料。因此，大自然给了我们一些最好和最独特的材料的灵感，比如壁虎脚、鲨鱼皮和荷叶。仿生材料试图通过模仿天然材料的结构来利用这数亿年的进化。不幸的是，自然材料往往很难或不可能在我们的实验室中复制，因为每一种新的生物材料通常都需要一个新的、量身定做的策略来将其作为人造材料复制。这样的策略，如果存在的话，往往是相当复杂的，限制了可能的材料成分，并使其难以扩大。“碳复制”天然材料的工艺将是一个完美的解决方案。这个项目将研究利用化学手段将天然物质矿化成金属氧化物的过程。这种矿化过程可以用于仿生材料的快速成型，方法是将天然材料的样品转化为结构相同但成分不同的金属氧化物样品。它还可以用于将农业和林业行业的生物质和生物废弃物的原料转化为新的增值材料，用于催化、能量储存和转换、吸附、传感和光学应用。该项目还纳入了一项全面计划，以增加任职人数不足的群体参与科技、经济、技术和经济活动的机会，并增加工业界和学术界任职人数不足群体的领导人和榜样人数。该计划将高中和社区外展活动与对高中生、本科生和研究生的培训和指导相结合。第2部分：技术和非水解性溶胶凝胶(NHSG)矿化演示了天然纤维素材料转化为具有结构保留的金属氧化物。然而，我们目前对固体材料是如何完成这一过程的，以及它是否可以应用于其他自然材料缺乏了解。这项研究的总体目标是了解NHSG对纤维素的矿化机理及其与其他天然材料的相容性。中心假设是，NHSG矿化与其他多糖和富氧聚合物相容，如果它们能被溶剂溶胀，并具有适当类型和数量的氧基团。强调拟议研究的基本原理是，所产生的理解将开启将天然材料转化为具有定制成分的金属氧化物的一般战略。PI计划通过以下具体目标来实现总体目标：(1)阐明纤维素材料的NHSG矿化机理；(2)阐明NHSG矿化与其他聚合物材料的相容性。为了完成特定的目标#1，PI将使用精心设计的纤维素材料，通过横截面扫描电子显微镜结合能量色散X射线光谱的元素图谱来研究转化过程。具体目标#2将通过测试NHSG矿化中具有广泛化学和结构性质的常见天然聚合物来完成，以了解实现有效转化对聚合物材料的要求。该项目还将支持对研究生、本科生和高中生的培训。高中生将被招待参加为期8周的暑期研究项目，他们将在那里进行研究并接受指导，以使他们能够继续接受STEM教育。总体而言，该项目将支持至少一名女性、一名代表不足的少数族裔学生和两名弱势学生参与STEM。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

PART 1: NON-TECHNICAL SUMMARYIt is widely appreciated that nature has been perfecting its materials since the first plants and animals appeared on Earth. Thus, nature gives us inspiration for some of the best and most unique materials, such as gecko feet, shark skin, and lotus leaves. Biomimetic materials try to capitalize on these hundreds of millions of years of evolution by mimicking the structures of natural materials. Unfortunately, natural materials are often difficult or impossible to reproduce in our laboratories since each new biomaterial generally requires a new, tailored strategy to reproduce it as a man-made material. Such strategies, if exist, are often quite intricate, limiting the possible material compositions and making them difficult to scale up. A process for "carbon copying" natural materials would be a perfect solution. This project will study a process of mineralization of natural materials into metal oxides using chemistry. Such mineralization process can then be used for quick prototyping of biomimetic materials by converting samples of natural materials into metal oxide samples with the same structure but varied compositions. It can also be used to convert feedstock of biomass and biowaste from agricultural and forestry industries into new, value-added, materials for catalysis, energy storage and conversion, adsorption, sensing, and optical applications. The project also integrates a comprehensive plan for increasing participation of underrepresented groups in STEM and the numbers of leaders and role models from underrepresented groups in industry and academia. This plan combines high-school and community outreach activities with training and mentoring of high school, undergraduate, and graduate students.PART 2: TECHNICAL SUMMARYNon-hydrolytic sol-gel (NHSG) mineralization demonstrated conversion of natural cellulosic materials into metal oxides with structure retention. However, we currently lack the understanding of how this process is completed for solid materials and if it can be applied to other natural materials. The overall objective of this research proposal is to understand the mechanism of NHSG mineralization of cellulose and its compatibility with other natural materials. The central hypothesis is that NHSG mineralization is compatible with other polysaccharides and oxygen-rich polymers if they can be swelled by the solvent and have an appropriate type and amount of oxygen groups. The rationale that underlines the proposed research is that the generated understanding will unlock a general strategy for converting natural materials into metal oxides with tailored composition. PI plans to achieve the overall objective by pursuing the following specific objectives: (1) elucidate mechanism of NHSG mineralization for cellulosic materials and (2) elucidate compatibility of NHSG mineralization with other polymeric materials. To complete Specific Objective #1, PI will use carefully designed cellulose materials to study the conversion process with cross-sectional scanning electron microscopy coupled with elemental mapping via energy-dispersive X-ray spectroscopy. Specific Objective #2 will be completed by testing common natural polymers with broad range of chemical and structural properties in NHSG mineralization to understand requirements for polymeric materials to achieve effective conversion. The project will also support training of graduate, undergraduate, and high school students. High school students will be hosted for an 8-week summer research project where they will conduct research and receive mentoring to empower them to continue into STEM education. Overall, the project will support participation of at least one woman, one underrepresented minority student, and two disadvantaged students in STEM.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.