Tactile Devices To Sense Touch on a Par with a Human Finger

Maheshwari, Vivek; Saraf, Ravi F.

doi:10.1002/anie.200703693

Cited by 180 publications

(121 citation statements)

References 121 publications

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“…The skin is the largest organ in the human body. It is mechanically self-healing, but if such behavior can be developed in artificial skin, then it shall prove to be the future for robots used by humans in daily life for numerous applications [48][49][50]. Due to unprecedented stretching or bending, rupture of this electronic artificial skin can occur in robots.…”

Section: Potential Application Of Self Healing Phenomena Of Graphenementioning

confidence: 99%

Self-healing phenomena of graphene: potential and applications

et al. 2016

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The present study investigates the self healing behavior of both pristine and defected single layer graphene using a molecular dynamic simulation. Single layer graphene containing various defects such as preexisting vacancies and differently oriented pre-existing cracks were subjected to uniaxial tensile loading till fracture occurred. Once the load was relaxed, the graphene was found to undergo self healing. It was observed that this self healing behaviour of cracks holds irrespective of the nature of pre-existing defects in the graphene sheet. Cracks of any length were found to heal provided the critical crack opening distance lies within 0.3-0.5 nm for a pristine sheet and also for a sheet with pre-existing defects. Detailed bond length analysis of the graphene sheet was done to understand the mechanism of self healing of graphene. The paper also discusses the immense potential of the self healing phenomena of graphene in the field of graphene based sub-nano sensors for crack sensing.

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Section: Potential Application Of Self Healing Phenomena Of Graphenementioning

confidence: 99%

Self-healing phenomena of graphene: potential and applications

et al. 2016

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“…Piezoresistive sensors transduce mechanical strain into an impedance change and are widely used due to their simple read-out mechanism, sensitivity to both pressure and flexion 19 and potentially high pixel density 20 . Very recently, a resistive-type pressure sensor made of self-healing materials was demonstrated, showing that the self-healing capability of natural skin could be mimicked in artificial electronic skins 21 .…”

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confidence: 99%

An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film

et al. 2014

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Pressure sensing is an important function of electronic skin devices. The development of pressure sensors that can mimic and surpass the subtle pressure sensing properties of natural skin requires the rational design of materials and devices. Here we present an ultrasensitive resistive pressure sensor based on an elastic, microstructured conducting polymer thin film. The elastic microstructured film is prepared from a polypyrrole hydrogel using a multiphase reaction that produced a hollow-sphere microstructure that endows polypyrrole with structure-derived elasticity and a low effective elastic modulus. The contact area between the microstructured thin film and the electrodes increases with the application of pressure, enabling the device to detect low pressures with ultra-high sensitivity. Our pressure sensor based on an elastic microstructured thin film enables the detection of pressures of less than 1 Pa and exhibits a short response time, good reproducibility, excellent cycling stability and temperature-stable sensing.

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“…[12][13][14] Many of resistive sensors use nanomaterial-embedded composites and exploit changes in contact resistance between the nanomaterials in the composite matrix (such as elastomer) under pressure loading, showing improved pressure sensitivity and mechanical flexibility compared to silicon-or metal-based piezoresistive sensors. [15] However, resistive tactile sensors suffer from signal drift due to temperature changes and require high power consumption. In addition, complicated circuit arrangement for multipoint recognition is regarded as a drawback to be addressed.…”

mentioning

confidence: 99%

Flexible, Transparent, Sensitive, and Crosstalk‐Free Capacitive Tactile Sensor Array Based on Graphene Electrodes and Air Dielectric

Pyo

Choi

Kim

2017

Adv Elect Materials

113

105

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optical transparency, and mechanical flexibility of the sensor are considered as essential requirements for use in future tactile sensing applications. To fulfill these demands, a broad range of materials, fabrication processes, and structural designs of the tactile sensor have been developed, [8] while sensing principles are mainly classified as either resistive [9][10][11] or capacitive types. [12][13][14] Many of resistive sensors use nanomaterial-embedded composites and exploit changes in contact resistance between the nanomaterials in the composite matrix (such as elastomer) under pressure loading, showing improved pressure sensitivity and mechanical flexibility compared to silicon-or metal-based piezoresistive sensors. [15] However, resistive tactile sensors suffer from signal drift due to temperature changes and require high power consumption. In addition, complicated circuit arrangement for multipoint recognition is regarded as a drawback to be addressed. [7,16] Compared to resistive tactile sensing mechanisms, capacitive tactile sensors have advantages in terms of temperature independence, low power consumption, stability against long-term signal drift, and easy multipoint recognition by simple assembly of row and column electrodes. [16,17] In general, the structure of a capacitive sensor consists of two parallel electrodes with a dielectric layer between them. Highly compressible dielectric materials are essential to achieve high sensitivity; a lower Young's modulus of the dielectric leads to greater deformation when pressure is applied to the sensor, resulting in a larger change in capacitance. Accordingly, considerable efforts have been devoted to using elastomers with low Young's modulus as dielectric materials, including polydimethylsiloxane (PDMS), [18] polyurethane, [19] or Ecoflex. [12] However, these low-modulus elastomers also tend to have high viscoelasticity, slowing their response and relaxation times. [20] To overcome this limitation and further improve the sensitivity, a few tactile sensors make use of the strategy of structuring the dielectric layer by fabricating a microstructured surface in an orderly fashion. [7,20,21] The microstructured dielectric layer led to much higher sensitivity and faster response/relaxation time by allowing a larger deformation compared to conventional capacitive sensors with a plain dielectric layer under equal applied pressure. Nevertheless, The development of sensitive, flexible, and transparent tactile sensors is of great interest for next-generation flexible displays and human-machine interfaces. Although a few materials and structural designs have been previously developed for high-performance tactile sensors, achieving flexibility, full transparency, and highly sensitive multipoint recognition without crosstalk remains a significant challenge for such systems. This work demonstrates a capacitive tactile sensor composed of two sets of facing graphene electrodes separated by spacers, which forms an air dielectric between them. The air gap facilitates mor...

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Tactile Devices To Sense Touch on a Par with a Human Finger

Cited by 180 publications

References 121 publications

Self-healing phenomena of graphene: potential and applications

Self-healing phenomena of graphene: potential and applications

An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film

Flexible, Transparent, Sensitive, and Crosstalk‐Free Capacitive Tactile Sensor Array Based on Graphene Electrodes and Air Dielectric

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