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1. Digital light processing of liquid crystal elastomers for self-sensing artificial muscles

   https://doi.org/10.1126/sciadv.abg3677  

   Li, Shuo; Bai, Hedan; Liu, Zheng; Zhang, Xinyue; Huang, Chuqi; Wiesner, Lennard W.; Silberstein, Meredith; Shepherd, Robert F. (July 2021, Science Advances)

   null (Ed.)

   Artificial muscles based on stimuli-responsive polymers usually exhibit mechanical compliance, versatility, and high power-to-weight ratio, showing great promise to potentially replace conventional rigid motors for next-generation soft robots, wearable electronics, and biomedical devices. In particular, thermomechanical liquid crystal elastomers (LCEs) constitute artificial muscle-like actuators that can be remotely triggered for large stroke, fast response, and highly repeatable actuations. Here, we introduce a digital light processing (DLP)–based additive manufacturing approach that automatically shear aligns mesogenic oligomers, layer-by-layer, to achieve high orientational order in the photocrosslinked structures; this ordering yields high specific work capacity (63 J kg −1 ) and energy density (0.18 MJ m −3 ). We demonstrate actuators composed of these DLP printed LCEs’ applications in soft robotics, such as reversible grasping, untethered crawling, and weightlifting. Furthermore, we present an LCE self-sensing system that exploits thermally induced optical transition as an intrinsic option toward feedback control. 

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2. Advances in 4D printing of liquid crystalline elastomers: materials, techniques, and applications

   https://doi.org/10.1039/D2MH00232A  

   Guan, Zhecun; Wang, Ling; Bae, Jinhye (July 2022, Materials Horizons)

   Liquid crystalline elastomers (LCEs) are polymer networks exhibiting anisotropic liquid crystallinity while maintaining elastomeric properties. Owing to diverse polymeric forms and self-alignment molecular behaviors, LCEs have fascinated state-of-the-art efforts in various disciplines other than the traditional low-molar-mass display market. By patterning order to structures, LCEs demonstrate reversible high-speed and large-scale actuations in response to external stimuli, allowing for close integration with 4D printing and architectures of digital devices, which is scarcely observed in homogeneous soft polymer networks. In this review, we collect recent advances in 4D printing of LCEs, with emphases on synthesis and processing methods that enable microscopic changes in the molecular orientation and hence macroscopic changes in the properties of end-use objects. Promising potentials of printed complexes include fields of soft robotics, optics, and biomedical devices. Within this scope, we elucidate the relationships among external stimuli, tailorable morphologies in mesophases of liquid crystals, and programmable topological configurations of printed parts. Lastly, perspectives and potential challenges facing 4D printing of LCEs are discussed. 

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3. Digital Light Process 3D Printing of Magnetically Aligned Liquid Crystalline Elastomer Free–forms

   https://doi.org/10.1002/adma.202414209  

   Herman, Jeremy A; Telles, Rodrigo; Cook, Caitlyn C; Leguizamon, Samuel C; Lewis, Jennifer A; Kaehr, Bryan; White, Timothy J; Roach, Devin J (December 2024, Advanced Materials)

   Liquid crystalline elastomers (LCEs) are anisotropic soft materials capable of large dimensional changes when subjected to a stimulus. The magnitude and directionality of the stimuli‐induced thermomechanical response is associated with the alignment of the LCE. Recent reports detail the preparation of LCEs by additive manufacturing (AM) techniques, predominately using direct ink write printing. Another AM technique, digital light process (DLP) 3D printing, has generated significant interest as it affords LCE free‐forms with high fidelity and resolution. However, one challenge of printing LCEs using vat polymerization methods such as DLP is enforcing alignment. Here, we document the preparation of aligned, main‐chain LCEs via DLP 3D printing using a 100 mT magnetic field. Systematic examination isolates the contribution of magnetic field strength, alignment time, and build layer thickness on the degree of orientation in 3D printed LCEs. Informed by this fundamental understanding, DLP is used to print complex LCE free‐forms with through‐thickness variation in both spatial orientations. The hierarchical variation in spatial orientation within LCE free‐forms is used to produce objects that exhibit mechanical instabilities upon heating. DLP printing of aligned LCEs opens new opportunities to fabricate stimuli‐responsive materials in form factors optimized for functional use in soft robotics and energy absorption. 

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4. Liquid crystal elastomers as substrates for 3D, robust, implantable electronics

   https://doi.org/10.1039/D0TB00471E  

   Maeng, Jimin; Rihani, Rashed T.; Javed, Mahjabeen; Rajput, Jai Singh; Kim, Hyun; Bouton, Ian G.; Criss, Tyler A.; Pancrazio, Joseph J.; Black, Bryan J.; Ware, Taylor H. (July 2020, Journal of Materials Chemistry B)

   null (Ed.)

   New device architectures favorable for interaction with the soft and dynamic biological tissue are critical for the design of indwelling biosensors and neural interfaces. For the long-term use of such devices within the body, it is also critical that the component materials resist the physiological harsh mechanical and chemical conditions. Here, we describe the design and fabrication of mechanically and chemically robust 3D implantable electronics. This is achieved by using traditional photolithography to pattern electronics on liquid crystal elastomers (LCEs), a class of shape programmable materials. The chemical durability of LCE is evaluated under accelerated in vitro conditions simulating the physiological environment; for example, LCE exhibits less than 1% mass change under a hydrolytic medium simulating >1 year in vivo . By employing twisted nematic LCEs as dynamic substrates, we demonstrate electronics that are fabricated on planar substrates but upon release morph into programmed 3D shapes. These shapes are designed to enable intrinsically low failure strain materials to be extrinsically stretchable. For example, helical multichannel cables for electrode arrays withstand cyclic stretching and buckling over 10 000 cycles at 60% strain while being soaked in phosphate-buffered saline. We envision that these LCE-based electronics can be used for applications in implantable neural interfaces and biosensors. 

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5. Liquid Crystal Elastomers Under Confinement: A Review of Template‐Based Fabrication and Applications

   https://doi.org/10.1002/adem.202501727  

   Zhang, Meng; Yang, Le; Ding, Xinyi; Scarbrough, James Phillip; Singh, Tushar Narayan; Yao, Yuxing; Li, Shucong; Wang, Xiaoguang (January 2026, Advanced Engineering Materials)

   Template‐assisted confinement has emerged as a versatile strategy for controlling the structure and function of liquid crystal elastomers (LCEs). By guiding mesogen alignment and polymer network formation within predefined geometries, these approaches enable LCEs with programmable actuation, optical properties, and mechanical responses. This review provides a comprehensive overview of templating methods for LCE fabrication, including planar substrates, porous scaffolds, droplet‐based confinement, colloidal assemblies, microstructured molds, fibrous templates, and direct ink writing. For each category, how the geometry, surface properties, and processing conditions influence alignment quality and material performance is highlighted. The unique capabilities and challenges associated with each method are also discussed. Finally, emerging directions such as hierarchical and reconfigurable templates, multifunctional composites, and applications in soft robotics, adaptive optics, and biomimetic systems are outlined. Overall, these insights highlight the growing potential of confinement‐guided approaches in advancing the next generation of responsive LCE materials. 

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