Directed Buckling of Molded LCE Sheets for Haptic Interfaces

ABSTRACT Liquid crystalline elastomers (LCEs) can undergo controlled shape deformations in response to heat or light, with the deformations determined by the anisotropy programmed into the material during fabrication. Here, we focus on a relatively thin LCE disk that is constrained at its boundary; within a constrained two‐dimensional surface, even small strains can result in large out‐of‐plane deformations and three‐dimensional shapes. Using theory and simulation, we show that the shape of the LCE layer can be tailored to control its buckling in the presence of light. The system is particularly advantageous for use in braille and other haptic interfaces, allowing a message to be inscribed on one side and read from the opposite side. Removing the light causes the LCE to return to its initial flat conformation providing a rewritable and re‐readable surface, which is also valuable for encryption applications. Additionally, by determining the elastic energy of LCE systems as a function time, we pinpoint conditions where the system exhibits distinctive snap‐through behavior. The accompanying sudden release of stored elastic energy is useful for low‐energy, fast actuation for soft robotics and mechanical switches.