Non-Convex Colloids and the Self-Assembly of Colloidal Diamond

ABSTRACT

The self-assembly of colloidal particles into the cubic diamond structure has been a longstanding goal because of its potential for making materials with a photonic band gap. These materials suppress the spontaneous emission of light and are valued for their applications as optical waveguides, filters, laser resonators, for improving light-harvesting technologies, and for other applications.

We experimentally demonstrate the self-assembly of colloidal diamond and understand how it works using a combination of experiment and simulation. One key factor for self-assembling colloidal diamond is particle shape. Using non-convex colloids provides orientational constraints that extend to the second-nearest-neighbor interactions, which has proved difficult to achieve in colloidal self-assembly. A second key factor is particle valency, defined using attractive tetrahedrally oriented particle patches. In addition to depletion and DNA-mediated interactions, entropy also plays an important role in defining the parameter space over which a diamond lattice self-assembles.

BIOGRAPHY

David Pine is the Julius, Roslyn, & Enid Silver Professor at New York University, with appointments in the Department of Physics and the Department of Chemical & Biomolecular Engineering. He was Chair of the Department of Chemical & Biomolecular Engineering at NYU from 2014-2021. He received his PhD in Physics from Cornell University in 1982. Prior to assuming his appointment at NYU, he was Professor and Chair of Chemical Engineering and Professor of Materials at UCSB. Before that, he was a Staff Physicist at Exxon Corporate Research and an Assistant Professor at Haverford College. He is broadly interested in soft materials, optical materials, self-assembly, and light scattering. Current research interests include non-equilibrium phase transitions, self-assembly of colloids and emulsions, DNA-coated particles, colloids with directional interactions, and photonic materials. He is a Fellow of the American Academy of Arts and Sciences, the American Association for the Advancement of Science, and the American Physical Society.