  We study the dynamics and conformation of polymers composed by active
monomers. By means of Brownian dynamics simulations we show that when the
direction of the self-propulsion of each monomer is aligned with the backbone,
the polymer undergoes a coil-to-globule-like transition, highlighted by a
marked change of the scaling exponent of the gyration radius. Concurrently, the
diffusion coefficient of the center of mass of the polymer becomes essentially
independent of the polymer size for sufficiently long polymers or large
magnitudes of the self-propulsion. These effects are reduced when the
self-propulsion of the monomers is not bound to be tangent to the backbone of
the polymer. Our results, rationalized by a minimal stochastic model, open new
routes for activity-controlled polymer and, possibly, for a new generation of
polymer-based drug carriers.
