Temperature-Controlled Reconfigurable Nanoparticle Binary Superlattices

RF Mao and E Pretti and J Mittal, ACS NANO, 15, 8466-8473 (2021).

DOI: 10.1021/acsnano.0c10874

The presence of diffusionless transformations during the assembly of DNA-functionalized particles (DFPs) is highly significant in designing reconfigurable materials whose structure and functional properties are tunable with controllable variables. In this paper, we first use a variety of computational models and techniques (including free energy methods) to address the nature of such transformations between face- centered cubic (FCC) and body-centered cubic (BCC) structures in a three-dimensional binary system of multiflavored DFPs. We find that the structural rearrangements between BCC and FCC structures are thermodynamically reversible and dependent on crystallite size. Smaller nuclei favor nonclose-packed BCC structures, whereas close-packed FCC structures are observed during the growth stage once the crystallite size exceeds a threshold value. Importantly, we show that a similar reversible transformation between BCC/FCC structures can be driven by changing temperature without introducing additional solution components, highlighting the feasibility of creating reconfigurable crystalline materials. Lastly, we validate this thermally responsive switching behavior in a DFP system with explicit DNA (un)hybridization, demonstrating our findings' applicability to experimentally realizable systems.

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