A light-fueled self-oscillating liquid crystal elastomer balloon with self-shading effect

Developing new self-oscillating systems would greatly expand their applications in intelligent machines, advanced robotics, and biomedical devices, due to their advantages of directly harvesting ambient energy and self-control. In this paper, we creatively proposed a light-fueled self-oscillating liquid crystal elastomer (LCE) balloon with self-shading coating, which is capable of self-oscillating under steady ambient illumination. Based on the well-established dynamic LCE model and the ideal gas model, the governing equation of the free-standing LCE balloon is formulated, and dynamics of the self-oscillation is studied theoretically. Numerical calculations show that the balloon always evolves into two kinds of motion modes: static mode and oscillation mode. The mechanism of the self-oscillation is elucidated by the self-shading effect of the opaque power coating, and the conditions for triggering the self-oscillation are further obtained numerically. In addition, the effects of system parameters on amplitude, frequency and equilibrium position are also investigated. Amplitude and frequency are mainly affected by light intensity, damping coefficient, mass density and contraction coefficient, while are independent on initial velocity. It is anticipated that the self-oscillating balloon constructed in this paper would be of benefit in autonomous, self-sustained machines and devices with the core feature of photo-mechanical transduction.