Bistable dielectric elastomer actuator with directional motion

Meng, Junxing; Qiu, Yu; Hou, Chengyi; Zhang, Qinghong; Li, Yaogang; Wang, Hongzhi

doi:10.1016/j.sna.2021.112889

Cited by 17 publications

(14 citation statements)

References 25 publications

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“…Wang et al developed a bistable out-of-plane dielectric elastomer actuator by adopting a bilayer structure made from BSEP and a passive layer, as illustrated in Figure 9d. [133] The BSEP film was synthesized by photopolymerizing SA with soft segment AC9307. Through adjusting the reactant ratio, its phase-transition point can be tuned around ambient temperature.…”

Section: Applications Based On Bistable Electro-mechanical Transductionmentioning

confidence: 99%

Section: Mechanism Of Optical Modulationmentioning

confidence: 99%

mentioning

confidence: 99%

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Stiffness Variable Polymers Comprising Phase‐Changing Side‐Chains: Material Syntheses and Application Explorations

et al. 2022

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lack the adaptability biological muscles have for variable working environments. Emerging opportunities in airborne and submarine vehicles, agricultural manipulations, biomedical devices, and wearable electronics require materials with variable rigidity to respond to dynamically changing conditions. [3][4][5][6] The mechanical impedance of such materials can be altered or fine-tuned to allow the system to adapt without a sophisticated control algorithm. For example, when grasping a fragile object such as an egg using a gripper, a stiffness variable material provides an adaptive contact force to optimally complete the task. Similarly, bio-inspired robots and wearable exoskeletons require stiffness variable materials capable of a large stiffness change to provide structural load-bearing and mechanical work output. In the softened state, the material can deform to locomote, maneuver, and absorb the energy arising from a collision or when interfacing with the human body. Some applications, such as medical endoscope designs, involve "move-and-hold" operations. This is where a variable-stiffness structure that holds a particular orientation in space or rigidly supports a load is able to become deformable on demand to change shape or reposition. [7] Other potential applications that can benefit from variable stiffness materials include biomechanically compatible sensor insertions for neural implants, vibration, and noise control in aerospace structures, and conformal shape morphing robotic systems. Requirements of Stiffness Variable MaterialsTo impart the perceived smart and adaptive systems with versatile and advantageous functionalities matching or surpassing those of natural systems, the stiffness variable materials should possess the following important features:1. Wide modulus variation: A range of modulus variation greater than 100 or even 1000-fold is required. A high modulus is desired for load-bearing and supporting freestanding structures, while a low modulus provides conformation, shape transformation, energy absorption, and dissipation. 2. Mild stimulus: A mild stimulus to trigger the stiffness variable operation, such as a narrow temperature span in Stiffness variable materials have been applied in a variety of engineering fields that require adaptation, automatic modulation, and morphing because of their unique property to switch between a rigid, load-bearing state and a soft, compliant state. Stiffness variable polymers comprising phase-changing side-chains (s-SVPs) have densely grafted, highly crystallizable long alkyl sidechains in a crosslinked network. Such a bottlebrush network-like structure gives rise to rigidity modulation as a result of the reversible crystallization and melting of the side chains. The corresponding modulus changes can be more than 1000-fold within a narrow temperature span, from ≈10 2 MPa to ≈10 2 kPa or lower. Other important properties of the s-SVP, such as stretchability, optical transmittance, and adhesion, can also be altered. This work reviews the underlying molecular mech...

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Section: Applications Based On Bistable Electro-mechanical Transductionmentioning

confidence: 99%

Section: Mechanism Of Optical Modulationmentioning

confidence: 99%

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Stiffness Variable Polymers Comprising Phase‐Changing Side‐Chains: Material Syntheses and Application Explorations

et al. 2022

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“…[44] For compliant electrodes, they should not interfere with the natural contraction and actuation of the dielectric material and should be robust enough to maintain high electrical conductance for rapid electric charging under high strains. As materials satisfying these conditions, carbon-based materials (carbon powder, grease, and conductive carbon black particles), [50,51] and metallic nanowires [52] have been frequently used for the fabrication of stretchable electrodes, and some literature comprehensively analyzed the flexible electrode. [45] DEAs have been extensively studied because of their rapid response, large actuation strain, low cost, ease of fabrication.…”

Section: Deasmentioning

confidence: 99%

A Review of Recent Advances in Electrically Driven Polymer‐Based Flexible Actuators: Smart Materials, Structures, and Their Applications

Ahn

Choi

et al. 2022

Adv Materials Technologies

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Polymer-based flexible actuators have recently attracted significant attention owing to their great potentials in soft robotics, wearables, haptics, and medical devices. In particular, electrically driven polymer-based flexible actuators are considered as some of the most practical actuators because they can be driven by a simple electrical power source. Over the past decade, research on electrically driven soft actuators has greatly progressed, leading to the development of various functional materials and bioinspired structures. This article comprehensively reviews recent advances in electrically driven soft actuators and compares their actuation performance based on working principles, materials, and structures. Several strategies, including combining smart materials and composite structures, which are proposed to overcome some of the drawbacks of electrically driven soft actuators, are also discussed. Finally, potential applications of electrically driven soft actuators in soft robotics are summarized and an outlook is presented.

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“…The high grafting density of bottlebrush-like long alkyl side chains on S-SVPs exhibit higher mobility than its main chain, providing relatively fast crystallization and high crystallinity . This means that S-SVPs can present a sharp phase transition over a narrow temperature range, resulting in relatively low energy consumption and fast transition from rigidity to flexibility, which is what soft robotics devices expect. , Recently, there have been many studies applying shape memory polymers to soft actuators to achieve variable stiffness − although they are commonly limited in application due to slow response or low range of stiffness variation . Therefore, it is expected to fabricate an S-SVP with fast response and wide range of stiffness variation toward soft actuator with fast actuate and tunable stiffness.…”

Section: Introductionmentioning

confidence: 99%

Stiffness Variable Polymer for Soft Actuators with Sharp Stiffness Switch and Fast Response

Liu

Wang

Huang

et al. 2023

ACS Appl. Mater. Interfaces

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Stiffness variable polymers are an essential family of materials that have aroused considerable attention in soft actuators. Although lots of strategies have been proposed to achieve variable stiffness, it remains a formidable challenge to achieve a polymer with a wide stiffness range and fast stiffness change. Herein, a series of variable stiffness polymers with a fast stiffness change and wide stiffness range were successfully synthesized, and the formulas were optimized via Pearson correlation tests. The rigid/soft stiffness ratio of the designed polymer samples can reach up to 1376-folds. Impressively, owing to the phase-changing side chains, the narrow endothermic peak can be observed with full width at half-maximum within 5 °C. Moreover, the shape memory properties of the shape fixity (R f ) and shape recovery ratio (R r ) values of the shape memory properties could reach up to 99.3 and 99.2%, respectively. Then, the obtained polymer was introduced into a kind of designed 3D printing soft actuator. The soft actuator can achieve sharp heating−cooling cycle of 19 s under a 1.2 A current with 4 °C water as coolant and can lift a 200 g weight at the actuating state. Moreover, the stiffness of the soft actuator can reach up to 718 mN/mm. The soft actuator exhibits an outstanding actuate behavior and stiffness switchable capability. We expect our design strategy and obtained variable stiffness polymers to be potentially applied in soft actuators and other devices.

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Bistable dielectric elastomer actuator with directional motion

Cited by 17 publications

References 25 publications

Stiffness Variable Polymers Comprising Phase‐Changing Side‐Chains: Material Syntheses and Application Explorations

Stiffness Variable Polymers Comprising Phase‐Changing Side‐Chains: Material Syntheses and Application Explorations

A Review of Recent Advances in Electrically Driven Polymer‐Based Flexible Actuators: Smart Materials, Structures, and Their Applications

Stiffness Variable Polymer for Soft Actuators with Sharp Stiffness Switch and Fast Response

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