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

该项目是通过“受限空间中的化学和运输(NSF-DFG Confinit)”机会获得的，这是一个由国家科学基金会和德国联邦科学基金会(DFG)参与的合作征集活动。胶体超粒子--由较小的纳米粒子(NP)制成的微米大小的球体--是一种用途广泛的材料。具有内部空隙的多孔超微粒因其催化、光子、药物输送和物理吸收特性而特别有价值。虽然超粒子可以通过溶剂干燥在液滴中组装纳米粒子来规模化制造，但人们对这些过程知之甚少。这个项目将使用计算机建模来解决这一知识差距，即多孔超粒子是如何形成的，它们的特性是如何工程设计的。此外，还将研究纳米粒子的形状和表面性质对组装过程和产品超粒子特性的影响。将开发的模型具有极大的潜力，可以缩短学术和工业环境中新材料的研发周期。这一国际合作将培养一支具有全球竞争力的劳动力队伍。该项目还将整合以下活动：(1)通过STEM本科生的暑期研究体验扩大对计算科学的参与，(2)为K-12学生开发关于扩散的虚拟现实教育活动，以及(3)传播开源软件和培训材料。该项目的目标是开发数学模型，研究干燥诱导的具有相互作用或形状各向异性的纳米颗粒(NP)组装成胶体超粒子的过程。人们对这一过程知之甚少，因为它涉及复杂的分子热力学和禁闭中的非平衡输运。将开发和验证基于多粒子碰撞动力学和经典动态密度泛函理论方法的互补粒子模型和连续介质模型。这些模型将被应用于具有各向异性吸引的“片状”NPs和形状各向异性的棒状NPs，这些NPs具有实现新的多孔超粒子组装的巨大潜力。将表征局部NP密度和取向顺序，以系统地询问NP属性和工艺条件(如干燥速度)如何决定超颗粒中的孔隙率分布。这项拟议的研究不仅将提高我们设计超粒子的能力，还将促进对核子的受限平流扩散过程的基本了解，包括相关过程，如冷冻干燥、过滤和沉积。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。

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.