Instability of an active-elastic chain

While active materials have drawn an explosion of interest recently, the researches are almost exclusively focused on active fluids.

Hereby, we created a simplest form of an active solid: a one-dimensional elastic chain comprising polar self-propelled centimeter scale particles. Combining rapid prototyping and precision desktop experiments, numerical simulations and theory, we report the emergence of the self-oscillating instability in such active chain. We further establish that the bifurcation towards the self-oscillatory dynamics is controlled by the competition between activity and elasticity.

The results provide some key insights into the potential of active solids in mimicking living matter and forming novel materials with far from equilibrium responses.