Large-area, flexible, integrable and transparent DEAs for haptics

Ankit, Ankit; Chan, Jun Yu; Nguyen, Loc H.; Krisnadi, Febby; Mathews, Nripan

doi:10.1117/12.2514267

Cited by 3 publications

(3 citation statements)

References 12 publications

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“…In contrast, electrically powered soft actuators made of elastomers are known for their high efficiencies, lightweight design, and superior structural compliance. , Dielectric elastomer actuators (DEAs) are compliant capacitors with an elastomeric layer sandwiched between electrodes where voltage application triggers Maxwell stresses, which result in actuation (Figure S1). , The integrability and versatility of DEAs have allowed them to be utilized in applications such as thin-film speakers, haptic surfaces, , optics, , biomimetic fish robots, as well as artificial muscles , and soft grippers . They have demonstrated high energy densities (0.5–19.8 J/kg) and significant actuation performance (2.5–70% actuation strain) .…”

Section: Introductionmentioning

confidence: 99%

High-k, Ultrastretchable Self-Enclosed Ionic Liquid-Elastomer Composites for Soft Robotics and Flexible Electronics

Ankit

Tiwari

et al. 2020

ACS Appl. Mater. Interfaces

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Soft robotics focuses on mimicking natural systems to produce dexterous motion. Dielectric elastomer actuators (DEAs) are an attractive option due to their large strains, high efficiencies, lightweight design, and integrability, but require high electric fields. Conventional approaches to improve DEA performance by incorporating solid fillers in the polymer matrices can increase the dielectric constant but to the detriment of mechanical properties. In the present work, we draw inspiration from soft and deformable human skin, enabled by its unique structure, which consists of a fluid-filled membrane, to create self-enclosed liquid filler (SELF)–polymer composites by mixing an ionic liquid into the elastomeric matrix. Unlike hydrogels and ionogels, the SELF–polymer composites are made from immiscible liquid fillers, selected based on interfacial interaction with the elastomer matrix, and exist as dispersed globular phases. This combination of structure and filler selection unlocks synergetic improvements in electromechanical propertiesdoubling of dielectric constant, 100 times decrease in Young’s modulus, and ∼5 times increase in stretchability. These composites show superior thermal stability to volatile losses, combined with excellent transparency. These ultrasoft high-k composites enable a significant improvement in the actuation performance of DEAslongitudinal strain (5 times) and areal strain (8 times)at low applied nominal electric fields (4 V/μm). They also enable high-sensitivity capacitive pressure sensors without the need of miniaturization and microstructuring. This class of self-enclosed ionic liquid polymer composites could impact the areas of soft robotics, shape morphing, flexible electronics, and optoelectronics.

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Section: Introductionmentioning

confidence: 99%

High-k, Ultrastretchable Self-Enclosed Ionic Liquid-Elastomer Composites for Soft Robotics and Flexible Electronics

Ankit

Tiwari

et al. 2020

ACS Appl. Mater. Interfaces

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“…These tactile feedback devices are based on different technologies such as electrostatics, piezoelectrics, Peltier elements, surface acoustic waves, air jets, pneumatics, electrorheological and magnetorheological fluids, microfluidics, and electroactive polymers. [ 8,16,17 ] However, most of the current generation of tactile feedback devices aim to simulate the perception of texture change via sensory manipulation; certain technologies aim to create actual topographical changes. [ 8 ]…”

Section: Introductionmentioning

confidence: 99%

Soft Actuator Materials for Electrically Driven Haptic Interfaces

Ankit

Nirmal

et al. 2021

Advanced Intelligent Systems

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Haptics involves human touch sensing and tactile feedback and plays a crucial role in physical interactions of humans with their environment. There is an ever‐increasing interest in development of haptic technologies, due to their role in various applications such as robotics, virtual and augmented reality, healthcare, and smart electronics. Electrically driven actuation mechanisms for soft materials like dielectric elastomer actuators (DEAs), electrohydraulic soft actuators (ESAs), ionic polymer−metal composites (IPMCs), and liquid crystal elastomers (LCEs) hold the potential for the development of the next generation of haptic feedback devices due to a variety of advantages such as light weight and compact design, untethered activation and control, large actuation strains, and distributed and localized actuation. Herein, a detailed look is taken at the advancement in material designs for these electrically driven soft actuators. A detailed analysis of the different strategies for improving the electromechanical performance of existing material systems is presented. Approaches adopted to synthesize novel material systems are explained. Advancements in compliant electrode materials for the electrically driven soft actuators are also described. The conclusion reflects on the main challenges in the field and provides perspectives on recent advancements expected to have a significant impact.

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“…Relative to conventional rigid electronic devices, soft and stretchable electronics transform how we utilize and fabricate electronics, paving the way for various futuristic applications such as conformable devices, electronic skins and soft robotics [1][2][3][4][5][6][7] . The ability to minimize loss in electronic function under large mechanical strain is essential to the progress of soft and stretchable devices [8,9] ; for example, "on-skin" electronics require undisrupted electrical conduction while stretching to remain functional while conforming to the skin [2,3,5] .…”

Section: Introductionmentioning

confidence: 99%

Directed Assembly of Liquid Metal–Elastomer Conductors for Stretchable and Self‐Healing Electronics

et al. 2020

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Due to the growing interest in soft robotics, stretchable electronics, and electronic skins, there is demand for compliant electrodes and interconnects that are soft, stretchable and conductive.Here, we use dielectrophoresis (DEP) to assemble, align, and sinter microdroplets of liquid metal-eutectic Ga-In (EGaIn)-in uncured polydimethylsiloxane (PDMS) to form electrically conducting microwires. There are several noteworthy aspects of this approach: (1) Generally, liquid metal droplets in silicone at loadings approaching 90 wt% remain insulating and form conductive network only when subjected to sintering. Here the use of DEP facilitates assembly of the filler droplets into conductive microwires at loadings as low as 10 wt% EGaIn. (2) Dielectrophoresis is done in silicone for the first time, enabling the microwires to be cured in a stretchable matrix. (3) Because the droplets are liquid, they sinter during dielectrophoresis to form a stretchable metallic microwire that retains its shape after curing the silicone and does not change resistance during mechanical strain. (4) The use of liquid metal eliminates the issue of compliance mismatch observed in soft polymers with solid fillers. (5) The silicone-EGaIn "ink" can be placed in holes created by severely damaged regions of stretchable wires to create stretchable interconnects that heal the damage both mechanically and electrically. We characterize the DEP process of this unique set of materials and demonstrate the interesting attributes enabled by such liquid microwires.

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Large-area, flexible, integrable and transparent DEAs for haptics

Cited by 3 publications

References 12 publications

High-k, Ultrastretchable Self-Enclosed Ionic Liquid-Elastomer Composites for Soft Robotics and Flexible Electronics

High-k, Ultrastretchable Self-Enclosed Ionic Liquid-Elastomer Composites for Soft Robotics and Flexible Electronics

Soft Actuator Materials for Electrically Driven Haptic Interfaces

Directed Assembly of Liquid Metal–Elastomer Conductors for Stretchable and Self‐Healing Electronics

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