|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Multiscale Architectured Materials (MAM II): Tailoring Mechanical Incompatibility for Superior Properties
||Self-assembled Nanoparticle Superlattices with High Elastic Modulus
||X. Wendy Gu, David Koshy, Xingchen Ye, Paul Alivisatos
|On-Site Speaker (Planned)
||X. Wendy Gu
Architectured materials made from nanoscale building blocks often exhibit extraordinary mechanical properties, but are difficult to fabricate with conventional techniques. Here, colloidal self-assembly is used to arrange polystyrene-grafted Au nanoparticles at a fluid interface to form ordered nanoparticle solids, or superlattices, with sub-10 nm features but overall dimensions of ~1 cm. A thin film buckling method is used to measure superlattice elastic modulus, which was as high as 120 GPa for a superlattice with 12 vol. % Au. Superlattices consisting of a single monolayer of nanoparticles have higher elastic moduli than superlattices with multilayer thicknesses. Additionally, elastic modulus is enhanced for superlattices that are self-assembled rapidly, which leads to structural defects like nanoparticle vacancies, dislocations and grain boundaries. We propose that the exceptional stiffness of self-assembled nanoparticle superlattices stems from the extreme confinement of polystyrene molecules between Au nanoparticles that arises during the highly non-equilibrium self-assembly process.