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Assembly of Linked Nanocrystal Colloids by Reversible Covalent Bonds

preprint
submitted on 11.09.2020 and posted on 14.09.2020 by Manuel Dominguez, Michael Howard, Josef Maier, Stephanie Valenzuela, Zachary Sherman, Lauren Reimnitz, Jiho Kang, Shin Hum Cho, Stephen Gibbs, Arjun Menta, Deborah Zhuang, Aevi van der Stok, Sarah Kline, Eric Anslyn, Thomas Truskett, Delia Milliron
The use of dynamically bonding molecules designed to reversibly link solvent-dispersed nanocrystals (NCs) is a promising strategy to form colloidal assemblies with controlled structure and macroscopic properties. In this work, tin-doped indium oxide NCs are functionalized with ligands that form reversible covalent bonds with linking molecules to drive assembly of NC gels. We monitor gelation using small angle X-ray scattering and characterize how changes in the gel structure affect infrared optical properties arising from the localized surface plasmon resonance of the NCs. The assembly is reversible because of the designed linking chemistry, and we disassemble the gels using two strategies: addition of excess NCs to change the ratio of linking molecules to NCs and addition of a capping molecule that displaces
the linking molecules. The assembly behavior is rationalized using a thermodynamic perturbation theory to compute the phase diagram of the NC–linking molecule mixture. Coarse-grained molecular dynamics simulations reveal the competition between loop and bridge linking motifs essential for understanding NC gelation. This combined experimental, computational, and theoretical work provides a platform for controlling and designing the properties of reversible colloidal assemblies that incorporate NC and solvent compositions beyond those compatible with other contemporary (e.g, DNA-based) linking strategies.

Funding

NIH OD021508-01

Center for Dynamics and Control of Materials

Directorate for Mathematical & Physical Sciences

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NSF GRFP DGE-1610403

Arnold O. Beckman Postdoctoral Fellowship

Near-field coupling between molecular vibrations and plasmonic metal oxide nanocrystals

Directorate for Mathematical & Physical Sciences

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Welch Foundation F1848

Welch Foundation F-1696

Welch Regents Chair F-0046

History

Email Address of Submitting Author

mndominguez@utexas.edu

Institution

University of Texas at Austin

Country

United States

ORCID For Submitting Author

0000-0002-9606-9234

Declaration of Conflict of Interest

None

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