Multiresponsive polymeric microstructures with encoded predetermined and self-regulated deformability

TLDR

Dynamic biological systems rely on arrays of actively deformable microstructures capable of nearly unlimited predetermined and self‑regulated reconfigurations, many of which remain unattainable in synthetic materials. The authors introduce stimuli‑responsive microstructures based on liquid‑crystalline elastomers that exhibit a broad range of hierarchical, mechanically unfavored deformation behaviors. By polymerizing prepolymer in patterned magnetic fields, they encode uniform mesogen orientation into the elastomers, enabling temperature‑driven prescribed deformations, and, with added light‑responsive moieties, provide three actuation modes—self‑bending toward light below the nematic–isotropic transition, magnetic‑field‑encoded deformation above it, and light‑directed motion above it—while patterning arrays for functions such as cargo release, image concealment, and light‑controlled reflectivity. The platform demonstrates multifunctional actuation and patterning that enable responsive cargo release, image concealment, and light‑controlled reflectivity, and is envisioned for applications in switchable adhesion, information encryption, autonomous antennae, energy harvesting, soft robotics, and smart buildings.

Abstract

Dynamic functions of biological organisms often rely on arrays of actively deformable microstructures undergoing a nearly unlimited repertoire of predetermined and self-regulated reconfigurations and motions, most of which are difficult or not yet possible to achieve in synthetic systems. Here, we introduce stimuli-responsive microstructures based on liquid-crystalline elastomers (LCEs) that display a broad range of hierarchical, even mechanically unfavored deformation behaviors. By polymerizing molded prepolymer in patterned magnetic fields, we encode any desired uniform mesogen orientation into the resulting LCE microstructures, which is then read out upon heating above the nematic–isotropic transition temperature (TN–I) as a specific prescribed deformation, such as twisting, in- and out-of-plane tilting, stretching, or contraction. By further introducing light-responsive moieties, we demonstrate unique multifunctionality of the LCEs capable of three actuation modes: self-regulated bending toward the light source at T < TN–I, magnetic-field–encoded predetermined deformation at T > TN–I, and direction-dependent self-regulated motion toward the light at T > TN–I. We develop approaches to create patterned arrays of microstructures with encoded multiple area-specific deformation modes and show their functions in responsive release of cargo, image concealment, and light-controlled reflectivity. We foresee that this platform can be widely applied in switchable adhesion, information encryption, autonomous antennae, energy harvesting, soft robotics, and smart buildings.