Photomechanical vibration energy harvesting based on liquid crystal elastomer cantilever

Abstract

Due to the coupling of external light stimuli with mechanical deformation, light induced responses of liquid crystal elastomer (LCE) cantilevers have been widely studied considering the prospective application in light energy harvesting devices. In this paper, a theoretical study about photomechanical vibration of a LCE cantilever is presented for the further application in energy harvester design. The emphasis is placed on the clarification of light induced inhomogeneous strain distribution on the cantilever responses. Through introducing the physical neutral surface deviation, the governing equation is reformed. The equations are solved by using the superposition method and the Duhamel integral. An empire equation for the maximum tip deflection of the cantilever with respect to characteristic parameters is formulated. The results show that the light induced inhomogeneous strain distribution could not be ignored. The predicted critical values to trigger cantilever vibration agree with the experiment result. This work paves a way to the accurate design of light harvester, light-driven actuators and sensors.

Programmable liquid crystal elastomer matrix through photomechanical responses

“…In this part, based on the above theoretical derivation, the spontaneous bending of an anisotropic LCE square plate and the structure design is investigated. In the following calculations, the relevant material parameters are given as: E // =1GPa, E ⊥ = 0.5GPa, G = 0.1Gpa, ν // =ν ⊥ = 0.5, T 0 = 0.4 s, η 0 = 0.00022 s −1 , P 0// =0.001, a = b = 10 h. [25,31] The light intensity is I 0 = 5kwm −2 . In addition, x = x=a , y = y=b , and w = w=h are used in the following discussions so that the effect of plate dimension on the spontaneous bending can be easily understood.…”

“…The similar experimental phenomenon was also observed by Serak et al [23] Li and Cai [24] theoretically studied the light driven bending vibration of LCE beam. Taking into account the light induced inhomogeneous strain distribution, Zhao and Liu [25] studied the photomechanical vibration energy harvesting of an LCE cantilever. Dunn [26] analyzed the curvatures of monodomain and polydomain LCE plates under the illumination stimuli.…”

Varied Alignment Methods and Versatile Actuations for Liquid Crystal Elastomers: A Review

“…change of stimulus sites and thus persistently actuates the motion of the LCE device. Several examples have adopted this stimulus form successfully, such as the LCE wheels and helical ribbons designed by Zhao and co-workers [4] the LCE light-fueled cantilever oscillators designed by White and co-workers, [34,111] and the LCE electric locomotives designed by Yang and co-workers. [112] Programming stimulus can achieve versatile actuations of LCEs by digital control of both stimulus sites and the stimulus intensity, thereby having a huge advantage in complex actuators and soft robots.…”

“…Inhomogeneous deformation generated by the local stimulus in the LCEs will induce the displacement of the centroid of a LCE device, which leads to the change of stimulus sites and thus persistently actuates the motion of the LCE device. Several examples have adopted this stimulus form successfully, such as the LCE wheels and helical ribbons designed by Zhao and co‐workers [ 4 ] the LCE light‐fueled cantilever oscillators designed by White and co‐workers, [ 34,111 ] and the LCE electric locomotives designed by Yang and co‐workers. [ 112 ]…”

Self-Jumping of a Liquid Crystal Elastomer Balloon under Steady Illumination

“…Among various and effective stimuli in the LCE systems, light stimulus is more convenient to induce self-feedback to achieve self-sustained oscillation [ 43 ]. Recently, light-fueled self-oscillation based on LCE has attracted the attention of many scientists, and a large number of light-fueled self-oscillating systems based on LCE have been developed [ 30 , 43 , 44 , 59 , 60 ].…”