NSF-DFG Confine: Building functional supraparticles through directed assembly of nonspherical nanoparticles under confinement

• Applicant: Professor Dr. Michael Engel
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 509443407

Crystallization is a universal phenomenon that underpins many natural and synthetic processes. Examples are the growth of snowflakes, solving the structure of proteins, and pharmaceutical drug discovery. Unlike the extensive experimental studies on crystallization in infinite space, crystallization in a confining geometry is a less explored, yet rich research topic with profound implications in phenomena as diverse as the growth of cellular aggregates, biological pattern formation, DNA packaging inside virus capsids, optoelectronics and efficient food packaging and transport. Colloidal crystallization of nanoparticles (NPs) under confinement (e.g., in emulsion droplets) creates defined and dispersible superstructures, so-called supraparticles. The over-arching objective of this proposal is to advance the design and synthesis of supraparticles by leveraging confined geometries to direct NP assembly and crystallization. Distinct from extensive computational and experimental studies on spherical NPs under confinement, our supraparticles will consist of tens to thousands of shape-anisotropic NPs. Our central hypothesis is that the in-terplay of NP shape, surface chemistry, and the influence of the confinement environment will unlock a rich diversity of supraparticles with precise three-dimensional arrangements. Our ex-perimental-computational team located in the USA and Germany will study the effects of NP characteristics (size, shape, composition, and ligand chemistries) and confinement conditions (dimensionality and curvature of confinement) to uncover the principles governing assembly pathways and phase behaviors of supraparticles. Our work will expand the toolbox of supra-particle-by-design and will stimulate future computational studies that go beyond hard polyhedra by incorporating realistic interparticle interactions. The supraparticles obtained are promising candidates for applications in plasmonic metamaterials, porous materials, recyclable catalysts, drug delivery, cosmetics, pharmaceutical and food sciences, among others. Our long-term goal is to create hierarchically ordered, application-ready supraparticles with tailored properties and maximum performance.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partner: Professor Dr. Xingchen Ye