  We investigate the aggregation and phase separation of thin, living T.
tubifex worms that behave as active polymers. Randomly dispersed active worms
spontaneously aggregate to form compact, highly entangled blobs, a process
similar to polymer phase separation, and for which we observe power-law growth
kinetics. We find that the phase separation of active polymerlike worms does
not occur through Ostwald ripening, but through active motion and coalescence
of the phase domains. Interestingly, the growth mechanism differs from
conventional growth by droplet coalescence: the diffusion constant
characterizing the random motion of a worm blob is independent of its size, a
phenomenon that can be explained from the fact that the active random motion
arises from the worms at the surface of the blob. This leads to a fundamentally
different phase-separation mechanism that may be unique to active polymers.
