Topological Defects in Nanoparticles and Superlattice Structure

Soft Condensed Matter & Physics of Living Systems Seminar: Prof. Alex Travesset, Iowa State University

Materials whose fundamental units are nanoparticles, instead of atoms or molecules, are gradually emerging as major candidates to solve many of the technological challenges of our century. Those materials also display unique structural, dynamical and thermodynamical properties, often reflecting deep underlying geometric and topological constraints.

In this talk, I will focus on crystalline assemblies of nanoparticles, i.e. supercrystals. I will discuss our ongoing program to predict the rational design of nanoparticle materials in three different experimental strategies: DNA programmable self-assembly, evaporation of organic solvents with nanoparticles having hydrocarbon as capping ligands, and a new strategy developed at Ames lab consisting of crystallization of nanoparticle neutral (uncharged) polymer brushes by induced electrostaticphase separation.

I will emphasize the case of binary systems, and the idea that nanoparticles can be viewed as q=1 skyrmions, whose textures (helicities) fully determine the structure of the presumed equilibrium lattice structure.

Biography

Alex Travesset got his PhD from the Universitat de Barcelona in 1997. After Postdoc positions in Syracuse University and University of Illinois at Urbana Champaign, he joined the faculty at the Department of Physics and Astronomy at Iowa State University, where he is now full professor. He also holds an appointment as an associated scientist at the Ames lab.