Structure, Dynamics, and Rheology of Realistic Gaussian-Core Fluids: Unexpected Anomalies and Their Macromolecular Origin

Weexperimentally investigate the structure, dynamics, and linearrheology of dendrimer solutions as a model system of Gaussian-corefluids and ultrasoft colloids, and compare the results with thoseobtained by the coarse-grained approach. In the overpacked regime,particles pack in a way similar to Bernal's celebrated plasticinemodel. Meanwhile, the interparticle interaction displays a counterintuitivesoftening under densification. Such behaviors result in transportproperties remarkably different from the predictions of the simpleGaussian-core model. Particularly, we find a strong coupling betweenthe rearrangement of interparticle configuration and intraparticledynamics. These unexpected observations demonstrate the decisive roleof intraparticle complexity in the structure and dynamics of ultrasoftcolloids.