468937 Controlled Self-Assembly of Polymer-Grafted Nanoparticles

Sunday, November 13, 2016: 4:30 PM
Golden Gate 4 (Hilton San Francisco Union Square)
Huikuan Chao and Robert A Riggleman, Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA

Two dimensional nanoparticle lattices can exhibit unique optical, electrical, and chemical properties giving rise to emerging applications for photovoltaic conversion, nanoelectronics and catalysis. In many applications, it is useful to be able to control the particle spacing, the crystal lattice formed, and the local composition of the lattice by co-locating nanoparticles of varying chemistry. However, control over all of these variables requires exquisite control over the interparticle interactions, and a large number of degrees of freedom affect the interactions. Achieving a particular structure by design requires solving the “inverse problem”, where one must optimize the chemistry to meet the structure or property that is desired. In recent years, a variety of examples have shown that one can finely control the interactions between nanoparticles through the use of polymers grafted onto the nanoparticle surface. In this talk, I will describe our efforts at solving the inverse design problem on polymer-grafted nanoparticles using an evolutionary design approach. By optimizing the polydispersity on a nanoparticle surface, we demonstrate that optimized polymer-grafting designs lead to square, honeycomb and hexagonal nanoparticle lattices. We show that surprisingly simple polymer chemistry can lead to these self-assembly structures. Finally, we present the investigation on the effective interactions of the nanoparticles and compare them against lattice forming pair-wise potentials from previous inverse design studies, showing the impact of many-body interactions.

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