Recent Progress on the Rheology of Giant Molecules

Abstract

Giant molecules are a new class of precise macromolecules whose constructing blocks are molecular nanoparticles, such as polyhedral oligomeric silsesquioxane (POSS), fullerene (C 60 ), etc., connected by different types of links with various molecular topologies in soft matter. These blocks are connected in 3D instead of chain-like. Thus, the dynamics of giant molecules cannot be described by the entanglement-dominated "reptation" dynamics, nor by the volume-fraction-determined caging effect as in the colloidal domain. Instead, they demonstrate different kinetics which are highly dependent on their sizes (diameters), bridging the conventional polymeric and colloidal systems. Further investigations into its unique dynamics will not only offer new properties for developing novel materials, but will also provide a deeper insight into the general principles of glass formation. In this review, the definition of giant molecules, their assemblies as well as their structural features are first introduced. The general dynamics of other systems, including the conventional polymeric and colloidal systems are briefly summarized. The recent progress of the rheological study of giant molecules is then focused upon. Finally, perspectives on this direction are proposed.

The Extreme of Disentanglement: 100-fold Viscosity Reduction in Model Single-Chain Nanoparticles

“…In previous works, G ′’s of low M w giant molecules − do show a slope of 0.67 involving hydrodynamic interactions. Bottle brushes − with short branches have also demonstrated this Zimm-like feature, and Rouse-like behavior appears at lower frequency when the backbone of bottle brushes is long enough .…”