Liquid crystal elastomer
(LCE) materials, which have been developed and investigated for four decades,
still lack real industrial applications. The fundamental obstacle is the modest
force of LCEs generated in the LC-to-isotropic phase transition process, which
is the most important actuation moment. Here we report an interpenetrating
liquid crystal polyurethane/polyacrylate elastomer material, consisting of one
main-chain polyurethane LCE and another liquid crystal polyacrylate thermoset
networks which are simultaneously polymerized. This two-way shape memory
material can reversibly shrink/expand under thermal stimulus, and shows ultrastrong
actuation-mechanic properties. With a maximum shrinkage ratio of 86% at 140 oC
which is beyond the LC-to-isotropic phase transition, its actuation blocking
stress, actuation work capacity, breaking strength and elastic modulus reach
2.53 MPa, 1267.7 KJ/m3, 7.9 MPa and 10.4 MPa respectively. Such a
LCE material can lift up a load 30000 times heavier than its own weight. We
hope the outstanding mechanical properties of this IPN-LCE material would pave
the way for the real industrial utilizations of LCE-based soft actuators.
