  Recent theoretical studies found that mixtures of active and passive
colloidal particles phase separate but only at very high activity ratio. The
high value poses serious obstacles for experimental exploration of this
phenomenon. Here we show using simulations that when the active and passive
particles are polymers, the critical activity ratio decreases with the polymer
length. This not only facilitates the experiments but also has implications on
the DNA organization in living cell nuclei. Entropy production can be used as
an accurate indicator of this non-equilibrium phase transition.
