The interfacial behavior of a liquid crystal elastomer film bonded to an orthotropic substrate under light illumination

Bilayer soft actuators composed of a liquid crystal elastomer (LCE) film and a soft substrate have been widely used in soft robotics, bioengineering, and other fields. The existence of stress concentration at the interface edge easily leads to delamination damage of layered structures. Therefore, this article focuses on the distribution of interfacial stresses of the light-driven LCE film/orthotropic substrate system. The governing equations of the LCE film/substrate system are derived. The distributions of peeling and shear stresses on the interface are given and validated by using the finite element method (FEM). The effects of light illumination intensity, light attenuation distance and the director direction on the distribution of interfacial stresses are comprehensively analyzed. It is found that the signs of the shear stress and peeling stress depend on the director direction. This indicates that aligning the director in a certain direction may enhance the interface strength. The results may be useful for designing light-responsive LCE bilayer drivers.