NSF-DFG Confine: Drying-induced assembly of colloidal supraparticles from anisotropic nanoparticles

该项目是通过“有限空间中的化学和运输（NSF-DFG限制）”机会授予的，这是一个涉及美国国家科学基金会和德国研究共同体（DFG）的合作招标。胶体超粒子-由较小的纳米粒子（NP）制成的微米级球体-是多功能材料。具有内部空隙的多孔超颗粒因其催化、光子、药物递送和物理吸收性质而特别有价值。虽然可以使用溶剂干燥在液滴内组装NP来大规模制造超颗粒，但这些过程知之甚少。该项目将使用计算机建模来解决多孔超粒子如何形成以及如何设计其特性的知识缺口。此外，纳米粒子的形状和表面性质的组装过程和产品的超微粒的特性的影响将被调查。将开发的模型具有显著的潜力，可以缩短学术和工业环境中新材料的研究开发周期。这种国际合作将培养一支具有全球竞争力的劳动力队伍。该项目还将整合活动，以（1）通过STEM中代表性不足的本科生的夏季研究经验，扩大对计算科学的参与，（2）为K-12学生开发一个关于传播的虚拟现实教育活动，以及（3）传播开源软件和培训材料。本项目的目标是开发数学模型来研究干燥诱导的纳米颗粒组装（纳米颗粒）相互作用或形状各向异性的胶体超颗粒。这个过程是知之甚少，因为它涉及复杂的分子热力学和非平衡运输的限制。补充粒子为基础的和连续模型-基于多粒子碰撞动力学和经典的动态密度泛函理论方法，分别-将开发和验证。该模型将被应用到“补丁”纳米粒子与各向异性的吸引力和棒状纳米粒子与各向异性的形状，具有显着的未开发的潜力，实现新的多孔超微粒组件。将表征局部NP密度和取向顺序，以系统地询问NP性质和加工条件（例如干燥速度）如何确定超颗粒中的孔隙率分布。这项研究不仅将提高我们设计超粒子的能力，而且还将推进对NP受限对流扩散过程的基本理解，包括相关过程，如冷冻干燥，过滤和沉淀。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This project was awarded through the “Chemistry and Transport in Confined Spaces (NSF-DFG Confine)" opportunity, a collaborative solicitation that involves the National Science Foundation and Deutsche Forschungsgemeinschaft (DFG). Colloidal supraparticles - micrometer-sized spheres made from smaller nanoparticles (NPs) - are versatile materials. Porous supraparticles with internal voids are particularly valued for their catalytic, photonic, drug delivery, and physical absorption properties. While supraparticles can be fabricated at scale using solvent drying to assemble NPs inside liquid droplets, these processes are poorly understood. This project will use computer modeling to address this knowledge gap in how porous supraparticles form and how their properties can be engineered. Furthermore, the nanoparticle shape and surface property effects on the assembly process and the characteristics of the product supraparticles will be investigated. The models that will be developed have significant potential to shorten the research & development cycle of new materials in both academic and industrial settings. This international collaboration will train a globally competitive work force. The project will also integrate activities to (1) broaden participation in computational science through a summer research experience for undergraduates underrepresented in STEM, (2) develop a virtual-reality educational activity on diffusion for K-12 students, and (3) disseminate open-source software and training materials.The goal of this project is to develop mathematical models to investigate the drying-induced assembly of nanoparticles (NPs) with interaction or shape anisotropy into colloidal supraparticles. This process is poorly understood because it involves complex molecular thermodynamics and nonequilibrium transport in confinement. Complementary particle-based and continuum models - based on the multiparticle collision dynamics and classical dynamic density functional theory approaches, respectively - will be developed and validated. The models will be applied to “patchy” NPs with anisotropic attraction and rodlike NPs with anisotropic shape that have significant untapped potential for realizing new porous supraparticle assemblies. The local NP density and orientational order will be characterized to systematically interrogate how both the NP properties and the processing conditions (such as the drying speed) determine the porosity distribution in the supraparticle. The proposed research will not only improve our ability to engineer supraparticles but also advance fundamental understanding of confined advection-diffusion processes for NPs, including related processes such as freeze drying, filtration, and sedimentation.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.