Alignment Strategies and Morphing Mechanisms in Liquid Crystal Elastomers: From Fundamentals to Advanced Applications.

Liquid crystal elastomers (LCEs) are smart materials that integrate the anisotropic properties of liquid crystals and the elasticity of polymers, enabling large, reversible shape changes in response to various external stimuli. These distinctive properties make LCEs a promising candidate for applications in actuators, soft robotics, sensors, and optics. The morphing behaviors of LCEs are fundamentally governed by the alignment of mesogenic molecules, which transition from ordered to disordered states upon stimulation, resulting in controllable shape transformations. Various alignment techniques exploiting the manipulation of mesogenic molecules are continuously explored as a way to effectively actuate morphing behaviors. This review provides an overview of key alignment techniques, including surface anchoring, field effect, and mechanical alignment, and explores how these methods support the design of tailored morphing properties for specific applications. The relationship between alignment and morphing behaviors in LCEs is discussed, offering a comprehensive overview of alignment-based morphing design strategies. Furthermore, the review highlights the significant potential of LCEs in advanced applications such as artificial muscles, actuators, and reconfigurable optical devices. By providing a foundational understanding of LCEs' alignment and morphing, this review aims to inspire more scientific innovations and technical advances in their design and application.