  Interplay between counterion-mediated interaction and stiffness inherent to
polymer chain can bring substantial complexity to the morphology and dynamics
of polyelectrolyte brush condensates. Trivalent counterions induce collapse of
flexible polyelectrolyte brushes, over a certain range of grafting density,
into octopus-like surface micelles; however, if individual chains are rigid
enough, the ion-mediated local nematic ordering assembles the brush chains into
fractal-like dendritic condensates whose relaxation dynamics is significantly
slower than that in the surface micelles. Notably, the trivalent ions condensed
in the dendritic condensates are highly mobile displaying quasi-one-dimensional
diffusion in parallel along the dendritic branches. Our findings in this study
are potentially of great significance to understanding the response of cellular
organization such as chromosomes and charged polysaccharides on membranes to
the change in ionic environment.
