Tuning Molecular-Level Polymer Conformations Enables Dynamic Control over Both the Interfacial Behaviors of Ag Nanocubes and Their Assembled Metacrystals
journal contributionposted on 03.07.2017, 00:00 by Yijie Yang, Yih Hong Lee, Chee Leng Lay, Xing Yi Ling
In surface chemistry-directed nanoparticle self-assembly, it remains challenging to continuously modulate nanoparticle behavior at the oil/water interface without replacing surface functionality or particle morphology. Here, we utilize solvent-tunable molecular-level polymer conformation changes to achieve “multiple metacrystals using one nanoparticle with one chemical functionality”. We use Ag nanocubes functionalized with a mixed monolayer of thiol-terminated poly(ethylene glycol) (PEG) and hexadecanethiol (C16). We continuously modulate PEG conformation from swollen to coiled states by decreasing solvent polarity, whereas C16 promotes nanocube dispersion in organic carrier solvents. Such PEG conformation changes drive Ag nanocubes to adopt tilted, standing, and planar configurations at the oil/water interface, with their interfacial positions changing from halfway across the interface to almost immersed within the oil phase. We also identify four specific polarities which enable Ag nanocubes to assemble into large-area metacrystals with linear, hexagonal, and square close-packed lattices. Our work establishes an innovative strategy to achieve robust tunability of nanoparticle interfacial behavior and unprecedented modulation of metacrystal structure.
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Ag Nanocubescarrier solventsparticle morphologypolarityPEG conformationsolvent-tunable molecular-level polymer conformation changesoil phasesurface functionalitymetacrystal structureinterfacesquare close-packed latticesSuch PEG conformation changes drive Ag nanocubesAssembled MetacrystalsTuning Molecular-Level Polymer Conformations Enables Dynamic ControlC 16surface chemistry-directed nanoparticle self-assemblyInterfacial Behaviorsuse Ag nanocubes functionalizednanoparticle behaviornanocube dispersionAg nanocubes