Complexity From Simplicity: Confinement Directs Morphogenesis And Motility In Nematic Polymers

Liquid crystalline polymers (LCP) that actuate under confinement adopt shapes with complexity that is upconverted beyond that encoded by their nascent patterning. Twisted nematic LCP thermally transform into simple spiral structures, when unconstrained. Confining them into rings or rigidly fixtured rectangular elasticas induces their self-assembly into supercoils, prismatic folded trusses, twisted and bent tape spring geometries. No additional material patterning, localized stimulation or training is required. Along its way, the actuation unlocks mechanical instabilities that can power impulsive responses. The self-assembled structures also sustain dynamic responses. These include motility via crawling and kinematic manipulation in a crank-rocker mechanism from an otherwise unstructured thermal stimulus. Interacting assemblages of the individually confined LCP build functionally relevant structures, including airframes and gripper-arm mimicking geometries. Thus, confinement is shown to free shape selection from a one-to-one correspondence to the blueprinted microstructure in active polymers. (c) 2021 Elsevier Ltd. All rights reserved.