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Formation of desired three-dimensional (3D) shapes from flat thin sheets with programmed non-uniform deformation profiles is an effective strategy to create functional 3D structures. Liquid crystal elastomers (LCEs) are of particular use in programmable shape morphing due to their ability to undergo large, reversible, and anisotropic deformation in response to a stimulus. Here we consider a rectangular monodomain LCE thin sheet divided into one high- and one low-temperature strip, which we dub a ‘bistrip’. Upon activation, a discontinuously patterned, anisotropic in-plane stretch profile is generated, and induces buckling of the bistrip into a rolled shape with a transitional bottle neck. Based on the non-Euclidean plate theory, we derive an analytical model to quantitatively capture the formation of the rolled shapes from a flat bistrip with finite thickness by minimizing the total elastic energy involving both stretching and bending energies. Using this analytical model, we identify the critical thickness at which the transition from the unbuckled to buckled configuration occurs. We further study the influence of the anisotropy of the stretch profile on the rolled shapes by first converting prescribed metric tensors with different anisotropy to a unified metric tensor embedded in a bistrip of modified geometry, and then investigating the effect of each parameter in this unified metric tensor on the rolled shapes. Our analysis sheds light on designing shape morphing of LCE thin sheets, and provides quantitative predictions on the 3D shapes that programmed LCE sheets can form upon activation for various applications. 

Aligned liquid crystal polymers are materials of interest for electronic, optic, biological and soft robotic applications. The manufacturing and processing of these materials have been widely explored with mechanical alignment establishing itself as a preferred method due to its ease of use and widespread applicability. However, the fundamental chemistry behind the required two‐step polymerization for mechanical alignment has limitations in both fabrication and substrate compatibility. In this work we introduce a new protection‐deprotection approach utilizing a two‐stage Diels–Alder cyclopentadiene‐maleimide step‐growth polymerization to enable mild yet efficient, fast, controlled, reproducible and user‐friendly polymerizations, broadening the scope of liquid crystal systems. Thorough characterization of the films by DSC, DMA, POM and WAXD show the successful synthesis of a uniaxially aligned liquid crystal network with thermomechanical actuation abilities.

 

Aligned liquid crystal polymers are materials of interest for electronic, optic, biological and soft robotic applications. The manufacturing and processing of these materials have been widely explored with mechanical alignment establishing itself as a preferred method due to its ease of use and widespread applicability. However, the fundamental chemistry behind the required two‐step polymerization for mechanical alignment has limitations in both fabrication and substrate compatibility. In this work we introduce a new protection‐deprotection approach utilizing a two‐stage Diels–Alder cyclopentadiene‐maleimide step‐growth polymerization to enable mild yet efficient, fast, controlled, reproducible and user‐friendly polymerizations, broadening the scope of liquid crystal systems. Thorough characterization of the films by DSC, DMA, POM and WAXD show the successful synthesis of a uniaxially aligned liquid crystal network with thermomechanical actuation abilities.

 

Multiaddressable architectures comprising light‐responsive photochromic molecules and different stimuli‐responsive components are appealing platforms for intelligent materials because of not only the potential diversity of components and corresponding properties, but also the functions resulting from their synergistic interactions. A variety of multiaddressable photochromic architectures are being designed to meet the demands of applications in different areas ranging from molecular machines to smart materials. This review highlights exciting recent advances in the field of multiaddressable systems that employ photoswitching molecules, specifically with regard to photo‐/chemical‐addressable, photo‐/pH‐addressable, photo‐/thermal‐addressable, photo‐/redox‐addressable, and multi‐photoaddressable architectures. Design concepts, crosstalk between different components, and photoswitch integration in these multiaddressable systems are discussed.

 

Patterning of nanoparticles (NPs) via photochemical reduction within thermally responsive hydrogel films is demonstrated as a versatile platform for programming light‐driven shape morphing and materials assembly. Responsive hydrogel disks, containing patterned metal NPs, form characteristic wrinkled structures when illuminated at an air/water interface. The resulting distortion of the three‐phase (air/water/hydrogel) contact lines induces capillary interactions between two or more disks, which are either attractive or repulsive depending on the selected pattern of light. By programming the shapes of the NP‐rich regions, as well as of the hydrogel objects themselves, the number and location of attractive interactions are specified, and the assembly geometry is controlled. Remarkably, appropriately patterned illumination enables sustained rotation and motion of the hydrogel disks. Overall, these results offer insight into a wide variety of shape‐programmable materials and capillary assemblies, simply by controlling the NP patterns and illumination of these soft materials.