UNS: Rapid synthesis of ordered mesoporous materials through microwave processing of cooperatively assembled composites

1510612-Vogt介孔（2 - 50 nm孔径）材料广泛用于从催化到药物递送到能量存储和产生的众多应用中。在大多数情况下，这些孔的连通性和尺寸对其性能至关重要。模板合成方法提供了一种控制这两种性质的途径。这些材料的典型直接合成方案涉及嵌段共聚物或表面活性剂与功能前体如溶胶凝胶纳米颗粒（NP）或结晶NP的组装。在许多情况下，这些材料的有效制造仍然具有挑战性，特别是对于复杂的过渡金属氧化物。即使是普通硅酸盐SBA-15的合成，标准工艺也包括48小时的水热合成和在550 ° C下煅烧5小时（另外3小时用于加热和冷却）。这些冗长的制造过程和能源密集型煅烧过程是对材料多样性和商业创新的重大限制。使用微波反应器可以将中孔硅酸盐的合成时间从几天减少到几小时。随着控制功率输出的微波技术的进步，有序介孔二氧化硅的完全合成，包括模板降解，可以在几个小时而不是几天内在一个步骤中进行。但是关于如何合理选择用于微波反应的前体和模板剂，使得能够在一个步骤中直接制备高功能有序介孔材料的信息有限。在这里，PI的目的是研究微波方法用于合成包括金属碳酸盐和氧化物在内的各种介孔材料的实用性。智力MeritThis项目将阐明自组装有序介孔材料的形态如何受到模板和前体选择的影响，并展示微波处理如何使混合金属氧化物纳米颗粒的形成成为可能，而这是使用传统方法不可能的。PI假设：（1）嵌段共聚物模板的热稳定性对于介孔材料的最终结构是关键的，（2）高通量筛选将使得能够鉴定其中可以（不能）获得有序介孔结构的组合物，（3）微波处理将使得能够合成通过常规途径不可及的组合物，和（4）卷对卷加工提供了快速和可规模化制造这些材料的连续途径。为了检验这些假设，PI将利用一系列系统的嵌段共聚物和金属硝酸盐-柠檬酸盐（Fe、Co、Ni和Mn）化学物质作为金属氧化物的前体。将使用傅里叶变换红外光谱（FTIR）和椭圆偏振法来检查金属硝酸盐向金属氧化物的转化和聚合物模板的降解。反应动力学将作为微波功率的函数进行检查，并与传统的热方法进行对比。化学转化将与通过小角X射线散射、原子力显微镜和X射线衍射阐明的结构相关，以提供关于原子晶体结构和自组装纳米结构的信息。最后，我们将对这些材料的电化学性能进行研究，以了解其结构如何影响基于这些自组装材料的电池和超级电容器的性能。更广泛的影响可持续的廉价能源是一个重大挑战。能量产生（太阳能电池）和存储（电池和超级电容器）性能可以通过对形态、孔隙率和界面改性进行控制来显著增强。通过该项目获得的理解可以为改善这些材料的性能提供指导，这些材料可以用于这些应用，这可以帮助美国实现能源独立。更广泛的教育影响将涉及代表性不足的本科生的参与。与阿克伦全球聚合物学院和圣文森特圣玛丽玛丽的合作伙伴关系将包括教师和高中学生的研究和传播到K-12学生的广泛受众，其中参与研究的高中学生将通过参加科学博览会比赛传播给其他K-12学生和家长。外联工作将包括研究生，他们因此将有机会在提高整体科学素养所需的技术水平较低的领域进行演讲。

1510612-VogtMesoporous (2-50 nm pore size) materials are widely used in numerous applications from catalysis to drug delivery to energy storage and generation. In most of these cases, the connectivity and size of these pores are critical to their performance. Templated synthetic methods provide one route to control both of these properties. The typical direct synthesis scheme for these materials involves the assembly of block copolymers or surfactants with functional precursors such as sol gel nanoparticles (NPs) or crystalline NPs. The efficient fabrication of these materials remains challenging in many cases, especially with regards to complex transition metal oxides. Even for the synthesis of a common silicate, SBA-15, the standard process involves 48 hours of hydrothermal synthesis and calcination at 550 °C for 5 hours (with an additional 3 hours for heating and cooling). These lengthy fabrication processes and energy intensive calcination processes are significant limitations to material diversity and commercial innovations. Using microwave reactors can reduce the synthesis time for mesoporous silicates from days to hours. With the advances in microwave technology for controlling power output, the full synthesis of ordered mesoporous silicas, including template degradation, can be performed in a single step in a few hours instead of days. But there is limited information on how to rationally select precursors and templates for use in microwave reactions that enable the direct fabrication of highly functional ordered mesoporous materials in a single step. Here the PI aims to investigate the utility of microwave methods for the synthesis of a diverse class of mesoporous materials including metal carbonates and oxides.Intellectual MeritThis project will elucidate how the morphology of self-assembled ordered mesoporous materials is impacted by the template and precursor selection and show how microwave processing enables the formation of mixed metal oxide nanoparticles that are not possible using conventional methods. The PI hypothesizes that (1) the thermal stability of the block copolymer template is critical to the final structure of the mesoporous material, (2) high throughput screening will enable identification of compositions where ordered mesoporous structure can(not) be obtained, (3) microwave processing will enable synthesis of compositions not accessible by conventional paths, and (4) roll-to-roll processing provides a continuous route to the rapid and scalable fabrication of these materials. To test these hypotheses, the PI will utilize a systematic series of block copolymers and metal nitrate-citrate (Fe, Co, Ni, and Mn) chemistry for precursors to the metal oxides. The conversion of the metal nitrate to metal oxide and the degradation of the polymer template will be examined using Fourier transform infrared spectroscopy (FTIR) and ellipsometry. The reaction kinetics will be examined as a function of microwave power and contrasted against conventional thermal methods. The chemical transformations will be correlated with the structure as elucidated by small angle x-ray scattering, atomic force microscopy, and x-ray diffraction to provide information on both the atomic crystal structure and the self-assembled nanostructure. Finally the electrochemical properties of these materials will be examined to understand how the structure impacts performance for batteries and supercapacitors based on these self-assembled materials.Broader ImpactSustainable, cheap energy is a significant challenge. Energy generation (solar cells) and storage (batteries and supercapacitors) properties can be significantly enhanced by exercising control over morphology, porosity, and interfacial modifications. The understanding garnered through this project could provide guidelines for improving the properties of these materials that could be utilized in these applications, which could help the US toward energy independence. The broader educational impact will involve participation of underrepresented undergraduate students. Partnerships with the Akron Global Polymer Academy and St. Vincent St. Mary's high school will include teachers and high school students in both research and dissemination to a broad audience of K-12 students, whereby high school students involved in the research will disseminate to other K-12 students and parents through participation in Science Fair competitions. The outreach efforts will include graduate students who will thus have an opportunity to present at less technical levels necessary for improving overall science literacy.