(471i) Linker-Mediated Assembly of Nanocrystal Gels

Inorganic nanocrystals (NCs) exhibit distinctive optical properties that are enhanced in mesoscale structures by coupling between NCs. Low-density gels consisting of percolated, kinetically arrested networks of NCs are particularly promising for realizing reconfigurable materials with tailored properties. Here, I will describe one strategy for controllable, reversible NC gelation using a linker molecule to mediate bonding between NCs. We use a combination of thermodynamic perturbation theory (TPT) and simulations to predict conditions for gelation that are determined macroscopically by the linker concentration and microscopically by the linker size and flexibility. Our simulations show a substantial fraction of linkers are lost to “loop” linking motifs that hinder assembly; we extend TPT to incorporate such motifs and suggest linker designs that reduce their prevalence. The linker properties also impact the assembled NC structure, and combinations of linkers with different properties promise independent tunability of the phase behavior and structure of the NC gel.