Programmable Buckling of Liquid Crystal Elastomer Microtubes via Topology in Molecular Orientations

Liquid crystal elastomers (LCEs) are highly stimuli-responsive materials with programmable shape morphing via engineering molecular orientations. This study explores the buckling behavior of 3D-printed LCE microtubes featuring topological defect profiles, revealing both wrinkled and unwrinkled buckling. The interplay between the director field topology and the height-radius ratio regulates the buckling mode. For microtubes with a +1 defect profile, the number of wrinkles correlates inversely with the height-radius ratio, with a threshold set by soft elasticity. For microtubes with defect charges other than +1, the number of wrinkles is determined by the balance between defect symmetry and height-radius ratio, and the wrinkles locate primarily in areas where directors align with the circumferential direction. These findings highlight the potential to program buckling behavior by optimizing dimensions and director topologies of LCEs, paving a way for new responsive and adaptive structures and devices.