Synchronized self-motion of two camphor boats

The synchronized self-motion of two camphor boats was investigated on a circular water route. Two kinds of synchronization, phase-locking and phase-oscillatory modes, could be produced by changing the temperature, the radius of the circular cell, and the mass of each boat. The nature of the synchronization is discussed in relation to the distribution of the camphor layer, which is an important factor in the driving force of self-motion. The essential features of synchronized motion were reproduced by a numerical calculation regarding the spatial distribution of the camphor layer at the air/water interface. We believe that the present results may be useful for realizing artificial motors or chemomechanical transducers, which mimic motor organs or organelles in living organisms under nonlinear and isothermal conditions.