Equilibrium phase diagram of semi-flexible polymer networks with linkers

We present the determination by numerical simulation of the equilibrium phase diagram of solutions of semi-flexible polymers with linker molecules. At low linker concentrations the solution forms an isotropic gel phase. At higher linker concentrations we encounter -depending on the properties of the linker molecules- bundle phases, liquid-crystalline mesophases with broken bond-orientational order that had been predicted by analytical theories, and in addition a novel equilibrium state: the cluster phase. Equilibrium condensation of semi-flexible polymers appears to be controlled by linker entropy. The results are compared with the phase behavior of solutions of biopolymers and linker proteins.