Light-Fueled Synchronization of Two Coupled Liquid Crystal Elastomer Self-Oscillators

Abstract

The synchronization and group behaviors of self-excited coupled oscillators are common in nature and deserve to be explored, for self-excited motions have the advantages of actively collecting energy from the environment, being autonomous, making equipment portable, and so on. Based on light-powered self-excited oscillators composed of liquid crystal elastomer (LCE) bars, the synchronization of two self-excited coupled oscillators is theoretically studied. Numerical calculations show that self-excited oscillations of the system have two synchronization modes, in-phase mode and anti-phase mode, which are mainly determined by their interaction. The time histories of various quantities are calculated to elucidate the mechanism of self-excited oscillation and synchronization. For strong interactions, the system always develops into in-phase synchronization mode, while for weak interaction, the system will evolve into anti-phase synchronization mode. Furthermore, the effects of initial conditions, contraction coefficient, light intensity, and damping coefficient on the two synchronization modes of the self-excited oscillation are investigated extensively. The initial condition generally does not affect the synchronization mode and its amplitude. The amplitude of self-oscillation always increases with increasing contraction coefficient, gravitational acceleration, and light intensity, while it decreases with the increasing damping coefficient. This work will deepen people’s understanding of the synchronization behaviors of self-excited coupled oscillators, and the theoretical framework could be extended to scenarios involving large-scale synchronization of the systems with numerous interacting oscillators.

Heat-Driven Synchronization in Coupled Liquid Crystal Elastomer Spring Self-Oscillators

“…The self-oscillation amplitude demonstrates a positive correlation with the increase of LCE elastic coefficient, thermal expansion coefficient, temperature gradient and characteristic time, while demonstrates a negative correlation with the increase of spring elastic coefficient and damping coefficient. Unlike existing work about self-oscillating synchronization systems based on active materials [ 7 , 70 ], this paper elucidates in detail the mechanism of the synchronization phenomenon. This study is expected to advance the comprehension of self-oscillator synchronization and provide its potential applications in diverse fields, including energy harvesting, power generation, detection, soft robotics, medical devices and micro/nanodevices.…”

“…Self-oscillation refers to the phenomenon where a system generates sustained oscillations or periodic changes without external excitation, due to internal coupling and feedback mechanisms [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. As a result, self-oscillating systems do not require a continuous energy supply from external sources, reducing energy consumption and system complexity.…”

“…Through ongoing research and development, scientists continue to discover new active materials with unique properties and enhanced performance, such as dielectric elastomers [ 25 ], hydrogels [ 26 , 27 ], ionic gels [ 13 ], thermal response polymers [ 28 ] and liquid crystal elastomer (LCE) [ 29 , 30 , 31 ]. These active substances produce different responses when stimulated by light [ 7 ], heat [ 9 ], electricity [ 32 ] and magnetism [ 33 ], and a variety of self-sustained motion modes have been established according to this property, for example, torsion [ 34 , 35 ], vibration [ 6 , 36 , 37 ], bending [ 38 , 39 , 40 , 41 , 42 ], swing [ 43 ], rolling [ 44 ], oscillating [ 45 ], jumping [ 46 , 47 ], rotation [ 48 ], buckling [ 49 , 50 ], twisting [ 51 ], stretching [ 52 ], eversion or inversion [ 53 ] and other movements. LCE, a unique material, possesses a hybrid nature that combines the characteristics of both liquid crystals and elastomers, which constitutes a polymer network structure resulting from the cross-linking of liquid crystal monomer molecules.…”

“…Currently, there are few research studies on the interaction and synchronization of self-oscillation systems with multiple responsive materials. Li et al investigated the synchronization of two coupled light-driven self-oscillating LCE pendulums [ 7 ]. The collective motion of two joint LCE oscillators based on the self-shadowing effect was investigated by Du et al [ 73 ].…”

Self-Sustained Chaotic Jumping of Liquid Crystal Elastomer Balloon under Steady Illumination

“…Furthermore, these materials have led to the engineering of diverse modes of self-sustained motion modes, each characterized by their own unique dynamics. These motion modes span from vibration [ 9 , 10 , 11 ], bending [ 12 , 13 , 14 , 15 ], rolling [ 16 , 17 ], torsion [ 18 , 19 ], stretching and contraction [ 20 , 21 ], to even swimming [ 22 ], oscillating [ 23 , 24 , 25 ], buckling [ 26 , 27 , 28 , 29 , 30 ], jumping [ 31 , 32 , 33 ], rotating [ 34 ], valving, or reversing [ 35 , 36 ]. Intricate nonlinear feedback mechanisms, including phenomena such as self-shading [ 26 ], the coupling of large deformations with chemical reactions [ 1 , 2 ], and the generation of photothermal surface tension gradients [ 37 , 38 ], make these self-sustained motion modes possible.…”