Measuring correlated dynamics in molecular glasses: Properties of molecular glasses change as they are made into nanometer sized films. Fakhraai and Riggleman showed that when the film thickness is reduced below 30 nm, the solid glass films become liquid-like and flow. This results in dewetting as shown in the figure.
The ‘micro-origami’ approach to making microrobotic devices is to form thin films that can fold themselves into desired, dynamically transformable shapes.
Nanocrystal “molecules” or “oligomers”: precise-number assemblies of nanocrystals with well-defined geometrical arrangements.
IRG-4 self-assembles, models, and measures these plasmonic metal nanocrystal oligomers in order to tailor their optical properties.
Penn-COMPASS Partnership: IRG4/Solvay/CNRS
IRG-4 creates new forms of matter by assembling nanometer-sized crystals into large, ordered, complex assemblies (nanocrystal superlattices.
Murray (IRG-4) and Donnio (CNRS) have synthesized a library of molecules (polycatenars) that enable new kinds of nanocrystals and superlattices.
Broader Impact
Disordered packings like sand piles and metallic glasses have arrangements of their constituent particles that appear very similar to those of a liquid. It is a very hard and long-standing problem to be able “look” at the particle arrangement and tell if the the system is rigid, and where flow will initiate if the system is deformed.
At the smallest length scales, disordered systems such as nanoparticle packings and glass resemble the grains of sand on a beach. Lacking a structure, it is very difficult to understand how they deform and flow. We use a technique called atomic force microscopy, in which a sharp probe “feels” and pokes at a sample to measure its shape and mechanical properties.
Hybrid cell-like vesicles were prepared by coassembling (glyco)dendrimersomes with bacterial membrane vesicles (BMVs) derived from E. Coli. These assemblies incorporated transmembrane proteins such as the small fusion protein MgrB tagged with a red fluorescent protein, and glycoconjugates such as lipopolysaccharides and glycoproteins from E. Coli.
Building complex three-dimensional (3D) materials from pre-programmed two-dimensional films presents exciting challenges and opportunities. To achieve this goal, researchers inspired by the paper folding techniques of origami and kirigami have successfully utilized the mechanical instabilities of thin films, such as buckling.
Probing and manipulating electronic band structures of 2D materials.
Study reveals thin film physics also manifests in random nanocomposite geometry.
