Precisely Controllable Artificial Muscle with Continuous Morphing based on "Breathing" of Supramolecular Columns.

Skeletal muscles are natural motors executing sophisticated work through precise control of linear contraction. Although various liquid crystal polymers-based artificial muscles have been designed, the mechanism based on mainly the order-disorder transition usually leads to discrete shape morphing, leaving arbitrary and precise deformation a huge challenge. Here, we present one novel photo-responsive hemiphasmidic side-chain liquid crystal polymer with a unique "breathing" columnar phase that enables continuous morphing. Due to confinement inside the supramolecular columnar assembly, the cooperative movements of side-chains and backbones generates a significant negative thermal expansion and leads to temperature-controllable muscle-like elongation/contraction in the oriented polymer strip. The irreversible isomerization of the photo-responsive mesogens result in the synergistic phototunable bending and high-contrast fluorescence change. Based on the orthogonal responses to heat and light, we further demonstrate controllable arm-like bending motions of this material, which is applicable in constructing advanced artificial muscles or intelligent soft robotics. This article is protected by copyright. All rights reserved.