Highly Stretchable Resistive Pressure Sensors Using a Conductive Elastomeric Composite on a Micropyramid Array

Choong, Chwee-Lin; Shim, Mun‐Bo; Lee, Byoung-Sun; Jeon, Sung-Jong; Ko, Dong-Su; Kang, Tae June; Bae, Ji-Hyun; Lee, Sung Hoon; Byun, Kyung‐Eun; Im, Jungkyun; Jeong, Yong Jin; Park, Jin Young; Park, Jong-Jin; Chung, U‐In

doi:10.1002/adma.201305182

Cited by 1,114 publications

(852 citation statements)

References 27 publications

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“…As a basic part of e‐skin, pressure sensors are attracting growing attention because they can detect tiny pressure change by converting an external force to electrical or other recognized signals 4, 5. This function makes them great potentials in wearable electronics, biomedical diagnostics, health monitoring, and so forth 6, 7, 8, 9.…”

Section: Introductionmentioning

confidence: 99%

Solution‐Processed Bilayer Dielectrics for Flexible Low‐Voltage Organic Field‐Effect Transistors in Pressure‐Sensing Applications

Yin

Liu

et al. 2018

Advanced Science

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Flexible pressure sensors based on organic field‐effect transistors (OFETs) have emerged as promising candidates for electronic‐skin applications. However, it remains a challenge to achieve low operating voltages of hysteresis‐free flexible pressure sensors. Interface engineering of polymer dielectrics is a feasible strategy toward sensitive pressure sensors based on low‐voltage OFETs. Here, a novel type of solution‐processed bilayer dielectrics is developed by combining a thick polyelectrolyte layer of polyacrylic acid (PAA) with a thin poly(methyl methacrylate) (PMMA) layer. This bilayer dielectric can provide a vertical phase separation structure from hydrophilic interface to hydrophobic interface which adjoins well to organic semiconductors, leading to improved stability and remarkably reduced leakage currents. Consequently, OFETs using the PMMA/PAA dielectrics reveal greatly suppressed hysteresis and improved mobility compared to those with a pure PAA dielectric. Using the optimized PMMA/PAA dielectric, flexible OFET‐based pressure sensors that show a record high sensitivity of 56.15 kPa−1 at a low operating voltage of −5 V, a fast response time of less than 20 ms, and good flexibility are further demonstrated. The salient features of high capacitance, good dielectric performance, and excellent reliability of the bilayer dielectrics promise a bright future of flexible sensors based on low‐voltage OFETs for wearable electronic applications.

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Section: Introductionmentioning

confidence: 99%

Solution‐Processed Bilayer Dielectrics for Flexible Low‐Voltage Organic Field‐Effect Transistors in Pressure‐Sensing Applications

Yin

Liu

et al. 2018

Advanced Science

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“…Single-sided microstructured films have been widely employed to enhance the performance of flexible pressure sensors 10,14,17,32 and triboelectric generators 11,22 . For pressure-sensitive piezoresistance, a flat indium tin oxide (ITO) film was used as the top electrode on the surface of micropatterned composite films (Fig.…”

Section: Multidirectional Force-sensing Capabilities Of Microstructurmentioning

confidence: 99%

“…Specifically, dome-shaped or hemisphere-shaped microstructures have been reported to induce a large change in contact area and localized stress concentration, which are advantageous for fabricating high-performance piezoresistive sensors 10 and triggering a large amount of triboelectric charge 11 and a high piezopotential in the piezoelectric devices 12 . On the other hand, a large variation in local strain and compressibility of pyramid-shaped microstructures enhance force sensitivity and expand the dynamic sensing range of e-skins [13][14][15] . Inspired by the hierarchical structures in nature, such as insect legs, gecko foots, and beetle wings, pillar-shaped microstructures have been reported to provide selective and directional force-sensing properties, as well as stress-confinement effects [16][17][18][19] .…”

Section: Introductionmentioning

confidence: 99%

Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins

et al. 2018

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Electronic skins (e-skins) with high sensitivity to multidirectional mechanical stimuli are crucial for healthcare monitoring devices, robotics, and wearable sensors. In this study, we present piezoresistive e-skins with tunable force sensitivity and selectivity to multidirectional forces through the engineered microstructure geometries (i.e., dome, pyramid, and pillar). Depending on the microstructure geometry, distinct variations in contact area and localized stress distribution are observed under different mechanical forces (i.e., normal, shear, stretching, and bending), which critically affect the force sensitivity, selectivity, response/relaxation time, and mechanical stability of e-skins. Microdome structures present the best force sensitivities for normal, tensile, and bending stresses. In particular, microdome structures exhibit extremely high pressure sensitivities over broad pressure ranges (47,062 kPa −1 in the range of <1 kPa, 90,657 kPa −1 in the range of 1-10 kPa, and 30,214 kPa −1 in the range of 10-26 kPa). On the other hand, for shear stress, micropillar structures exhibit the highest sensitivity. As proof-of-concept applications in healthcare monitoring devices, we show that our e-skins can precisely monitor acoustic waves, breathing, and human artery/carotid pulse pressures. Unveiling the relationship between the microstructure geometry of e-skins and their sensing capability would provide a platform for future development of high-performance microstructured e-skins.

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“…24 DT DVP is defined as the time delay between the systolic and diastolic peaks. 18 The RI and SI are estimated to be 53% and 7.6, respectively, indicating the healthy state of a 30-year-old man. 34 Figure 3a schematically shows how the temperature can be monitored with the fabricated MF sensor using the thermoelectric effect.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, MWCNT-PANI nanocomposites have shown superior performance in terms of the Seebeck coefficient, electrical conductivity and thermal conductivity compared with their individual components. 16,17 As an excellent alternative candidate to overcome the narrow pressure range and low sensitivity of thin film-based pressure and gas sensors consisting of nanowires, nanoparticle and 3-dimensionally structured electrodes, [18][19][20] conductive porous foams are expected to be promising owing to their electronic conductivity and mechanical 1 flexibility. 21 Thus porous foams coated with conductive nanomaterials can be used for fabrication of high-performance pressure, temperature and gas sensors owing to their combined advantages of electronic conductivity, mechanical flexibility and large specific surface area.…”

Section: Introductionmentioning

confidence: 99%

Polyurethane foam coated with a multi-walled carbon nanotube/polyaniline nanocomposite for a skin-like stretchable array of multi-functional sensors

Hong

Park

et al. 2017

NPG Asia Mater

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Body-attachable sensors can be applied to electronic skin (e-skin) as well as safety forewarning and health monitoring systems. However, achieving facile fabrication of high-performance, cost-effective sensors with mechanical stability in response to deformation due to body movement is challenging. Herein we report the material design, fabrication and characteristics of a skin-like stretchable array of multi-functional (MF) sensors based on a single sensing material of polyurethane foam coated with multi-walled carbon nanotube/polyaniline nanocomposite, which enables simultaneous detection of body temperature, wrist pulse and ammonia gas. These sensors exhibit high sensitivity, fast response and excellent durability. Furthermore, the fabricated sensor array shows stable performance under biaxial stretching up to 50% and attachment to skin owing to the use of directprinted Galinstan liquid metal interconnections. This work proposes a facile method for fabrication of high-performance, stretchable MF sensors via appropriate selection of sensor design and functional materials that are applicable to e-skin and health monitoring systems. NPG Asia Materials (2017) 9, e448; doi:10.1038/am.2017.194; published online 17 November 2017 INTRODUCTIONWearable electronics have attracted considerable attention for use in electronic skin (e-skin) and health monitoring systems in order for a comfortable and secure life. 1-5 e-Skin is a human interactive device that can simultaneously sense signals from the body and respond to the environment. Thus it should be capable of measuring the five types of senses (taste, sight, hearing, olfactory and touch sensation) with high sensitivity and show mechanical stability against deformation due to skin movement. As a result, e-skin is required to be very thin and have a strain-relaxed design. 6 Because of the increasing importance of e-skin, extensive efforts have been undertaken to develop various sensors with high sensitivity. 7 Beyond the conventional sensor that can detect a single stimulus, novel advanced sensors for simultaneous monitoring of multiple stimuli (multi-functional (MF) sensors) have been actively investigated. 8,9 For practical application of such MF sensors, it is necessary to eliminate the interference between different stimuli that is commonly observed in conventional MF sensors, 10 in addition to fabricating cost-effective sensors on a deformable substrate. Development of MF sensors that transduce different stimuli into separate signals can intrinsically minimize signal interference, thus allowing for sensitive detection of multiple parameters, such as temperature and pressure, in a single device without decoupling analysis. Many power-

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Highly Stretchable Resistive Pressure Sensors Using a Conductive Elastomeric Composite on a Micropyramid Array

Cited by 1,114 publications

References 27 publications

Solution‐Processed Bilayer Dielectrics for Flexible Low‐Voltage Organic Field‐Effect Transistors in Pressure‐Sensing Applications

Solution‐Processed Bilayer Dielectrics for Flexible Low‐Voltage Organic Field‐Effect Transistors in Pressure‐Sensing Applications

Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins

Polyurethane foam coated with a multi-walled carbon nanotube/polyaniline nanocomposite for a skin-like stretchable array of multi-functional sensors

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