Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals

Guo, Yubing; Peng, Chenhui; Sun, Kai; Yaroshchuk, O.; Lavrentovich, Oleg D.; Wei, Qi

doi:10.3390/cryst7010008

Cited by 29 publications

(11 citation statements)

References 44 publications

(52 reference statements)

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“…As the concentration is increased or temperature is lowered, isotropic (I) solutions can order into nematic (N), columnar (M), and rectangular (O) phases. [29][30][31][32][33][34] A variety of strategies can be used to pattern the molecular orientation of LCLCs, such as surface anchoring controlled by grooved surfaces or photoaligned dyes, [35][36][37][38] 3D confinement, 39,40 and magnetic fields. 41 These methods have enabled spatial control over the alignment of LCLCs.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic, porous hydrogels templated by lyotropic chromonic liquid crystals

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Section: Introductionmentioning

confidence: 99%

Anisotropic, porous hydrogels templated by lyotropic chromonic liquid crystals

et al. 2020

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“…The inclusion of additional heaters and localization of Kapton films enables the preparation of a composite material system capable of motility (Figure 22c). Zhao and co‐workers also employed Joule‐heating to prepare to a series of LCN actuators 575. These authors assimilated shape memory processing of a glassy LCN via compression molding to realize a reversible gripper, walkers, and a conveyor.…”

Section: Liquid Crystal Elastomers and Networkmentioning

confidence: 99%

Materials as Machines

2020

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of responsive materials as machines is in robotics. The vision, leadership, and research of Bar-Cohen is seminal in both invigorating and focusing current-day research activities to develop responsive materials [2] and implement [3] them as lightweight, dexterous, and gentle (e.g., soft) robotic elements. In this spirit, this review exhaustively details the materials, the nature of their stimuli-response, and discusses considerations for their implementation in robotic systems and subsystems.Robotics is a well-established but growing field of research. Sustained progress in both performance and functionality continue to be realized in commercial robotic systems largely based on conventional materials and their integration with mechanisms. A recent example is the Atlas robot from Boston Dynamics [4] (Figure 1a). The incorporation of stimuli-responsive materials in robotics has largely focused on component-level demonstrations to extend the performance of a subsystem (such as a hand or gripper).Stimuli-responsive materials, spanning nearly all classes of materials and size scales, are currently subject to widespread examination in corporate, government, and academic research laboratories (Figure 1b-d). [5][6][7] In some cases, these materials have already found widespread commercial implementation in end use and are comparatively mature. The materials and fundamentals of their responses are summarized in Figure 2. Shape memory alloys (SMAs) and ceramic piezoelectric materials are distinctive in that they are hard, stimuli-responsive materials. Deformation of these materials can produce large energy densities due to their inherent stiffness. Electroactive polymers (EAPs) remain a topic of considerable interest, particularly dielectric elastomer actuators (DEAs). Engineered systems are rapidly emerging and enabling performance gains in robotics, largely based on pneumatic or fluidic (such as HASEL [8] actuators) transport processes that localize deformation to generate force or produce motion. Soft materials, such as shape memory polymers (SMPs), hydrogels, and liquid crystalline polymer networks (LCNs) and elastomers (LCEs) may offer distinctive functional performance to robotic systems in allowing local control of deformation without the need for complex interfacing with mechanisms. As will be evident, each of these materials has inherent advantages and performance tradeoffs that must be considered in functional implementations. However, responsive material systems have a common obstacle to widespread use: the performance and Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walk...

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“…[ 3,4 ] Later, one‐step polymerization with the in situ molecular alignment of reactive diacrylate mesogens introduced densely cross‐linked LC networks (LCNs), which were able to demonstrate out‐of‐plane shape changes (2D‐to‐3D transformation). [ 5,6 ] Advances in the control of molecular order in one‐step film processing techniques, such as application of external fields [ 7,8 ] and different surface alignment and photo‐patterning techniques, [ 9–22 ] led to various 2D‐to‐3D deformation profiles of varying degrees of complexity.…”

Section: Figurementioning

confidence: 99%

3D Microstructures of Liquid Crystal Networks with Programmed Voxelated Director Fields

2020

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The shape‐shifting behavior of liquid crystal networks (LCNs) and elastomers (LCEs) is a result of an interplay between their initial geometrical shape and their molecular alignment. For years, reliance on either one‐step in situ or two‐step film processing techniques has limited the shape‐change transformations from 2D to 3D geometries. The combination of various fabrication techniques, alignment methods, and chemical formulations developed in recent years has introduced new opportunities to achieve 3D‐to‐3D shape‐transformations in large scales, albeit the precise control of local molecular alignment in microscale 3D constructs remains a challenge. Here, the voxel‐by‐voxel encoding of nematic alignment in 3D microstructures of LCNs produced by two‐photon polymerization using high‐resolution topographical features is demonstrated. 3D LCN microstructures (suspended films, coils, and rings) with designable 2D and 3D director fields with a resolution of 5 µm are achieved. Different shape transformations of LCN microstructures with the same geometry but dissimilar molecular alignments upon actuation are elicited. This strategy offers higher freedom in the shape‐change programming of 3D LCN microstructures and expands their applicability in emerging technologies, such as small‐scale soft robots and devices and responsive surfaces.

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Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals

Cited by 29 publications

References 44 publications

Anisotropic, porous hydrogels templated by lyotropic chromonic liquid crystals

Anisotropic, porous hydrogels templated by lyotropic chromonic liquid crystals

Materials as Machines

3D Microstructures of Liquid Crystal Networks with Programmed Voxelated Director Fields

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