Liquid Crystal Elastomer
Lattices With Thermally
Programmable Deformation
Via Multi-Material 3D Printing

Arda  Kotikian,  Audrey  A.  Watkins,  Giovanni  Bordiga,  Andrew  Spielberg, Zoey  S.  Davidson,  Katia Bertoldi, and Jennifer A. Lewis

Here, we report the design, modeling, and fabrication of soft architected lattices composed of multiple LCEs that exhibit programmable and predictable deformation sequences in response to heat. By directly  printing multiple  LCE  inks  with  disparate  actuation  temperatures,  we created triangular cellular lattices in which each strut is composed of a given LCE with director alignment parallel to the strut direction. As controls, we first fabricate homogenous triangular lattices with low TNI(LTNI)  or  highTNI (HTNI) LCE  struts,  characterize  their  deformation  response  and  stiffness  as  a function of temperature, and then use these data to validate our simplified spring model. Next, we design, fabricate, and characterize heterogeneous triangular lattices. By co printing two LCEs with disparate TNI values, we encode varying deformation modes in lattices with the same global geometry, yet different localized compositional topology that are thermally triggered on demand. These soft architected  lattices  exhibit  shear-induced  configurations.  We  also  generated  nonperiodic  LCE lattices  that  exhibit  more  complex  shape  morphing  sequences  upon  heating. Lastly, we  introduce  an inverse design framework to automatically discover binary distributions of LTNI and HTNI LCE struts that encode transformations between multiple target shapes upon monotonic heating.