Segregation dynamics in active-passive mixtures of semiflexible filaments

We study the segregation of motile semiflexible filaments from a background of similar but nonmotile filaments. Our Langevin dynamics simulations reveal a wide range of emergent structures governed by filament flexibility and activity, i.e., self-propulsion strength. The system segregates at low activities, while at high activities it undergoes remixing. This is a characteristic feature of semiflexible active filaments which is not seen in rigid active particle systems. We show that collision-induced softening of single filaments is the dominant mode for this remixing. We provide a scaling argument for the lowering of the active polymer stiffness and show that it agrees well with the lowering of the segregation order parameter. We expect that our studies will shed light on the spatial organization of biofilaments within the cell, on the plasma membrane, and beyond, and help in the design of novel biomaterials whose structure can be tuned via the properties of the active or the passive filaments.