Hybrid Architectures of Heterogeneous Carbon Nanotube Composite Microstructures Enable Multiaxial Strain Perception with High Sensitivity and Ultrabroad Sensing Range.

Low-dimensional nanomaterials are widely adopted as active sensing elements for electronic skins. When the nanomaterials are integrated with microscale architectures, the performance of the electronic skin is significantly altered. Here, it is shown that a high-performance flexible and stretchable electronic skin can be produced by incorporating a piezoresistive carbon nanotube composite into a hierarchical topography of micropillar-wrinkle hybrid architectures that mimic wrinkles and folds in human skin. Owing to the unique hierarchical topography of the hybrid architectures, the hybrid electronic skin exhibits versatile and superior sensing performance, which includes multiaxial force detection (normal, bending, and tensile stresses), remarkable sensitivity (20.9 kPa-1 , 17.7 mm-1 , and gauge factor of 707 each for normal, bending, and tensile stresses), ultrabroad sensing range (normal stress = 0-270 kPa, bending radius of curvature = 1-6.5 mm, and tensile strain = 0-50%), sensing tunability, fast response time (24 ms), and high durability (>10 000 cycles). Measurements of spatial distributions of diverse mechanical stimuli are also demonstrated with the multipixel electronic skin. The stress-strain behavior of the hybrid structure is investigated by finite element analysis to elucidate the underlying principle of the superior sensing performance of the electronic skin.

[1]  S. Chen,et al.  Multiscale Wrinkled Microstructures for Piezoresistive Fibers , 2016 .

[2]  Peyman Servati,et al.  Effects of inter-tube distance and alignment on tunnelling resistance and strain sensitivity of nanotube/polymer composite films , 2012, Nanotechnology.

[3]  Qian Wang,et al.  Bubble‐Decorated Honeycomb‐Like Graphene Film as Ultrahigh Sensitivity Pressure Sensors , 2015 .

[4]  Sung Youb Kim,et al.  Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins , 2018, NPG Asia Materials.

[5]  Ning Hu,et al.  Piezoresistive Strain Sensors Made from Carbon Nanotubes Based Polymer Nanocomposites , 2011, Sensors.

[6]  John A. Rogers,et al.  Highly Sensitive Skin‐Mountable Strain Gauges Based Entirely on Elastomers , 2012 .

[7]  Geun Yeol Bae,et al.  Linearly and Highly Pressure‐Sensitive Electronic Skin Based on a Bioinspired Hierarchical Structural Array , 2016, Advanced materials.

[8]  Benjamin C. K. Tee,et al.  Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers. , 2010, Nature materials.

[9]  Changyu Shen,et al.  Organic vapor sensing behaviors of conductive thermoplastic polyurethane–graphene nanocomposites , 2016 .

[10]  Z. Suo,et al.  A transparent bending-insensitive pressure sensor. , 2016, Nature nanotechnology.

[11]  Seung Hwan Ko,et al.  Highly Sensitive and Stretchable Multidimensional Strain Sensor with Prestrained Anisotropic Metal Nanowire Percolation Networks. , 2015, Nano letters.

[12]  LuNanshu,et al.  Flexible and Stretchable Electronics Paving the Way for Soft Robotics , 2014 .

[13]  Jinyou Shao,et al.  Flexible three-axial tactile sensors with microstructure-enhanced piezoelectric effect and specially-arranged piezoelectric arrays , 2018 .

[14]  Zhibin Yu,et al.  User-interactive electronic skin for instantaneous pressure visualization. , 2013, Nature materials.

[15]  Zhanhu Guo,et al.  Polydimethylsiloxane-titania nanocomposite coating: Fabrication and corrosion resistance , 2018 .

[16]  Saeed Ahmed Khan,et al.  Pyramid microstructure with single walled carbon nanotubes for flexible and transparent micro-pressure sensor with ultra-high sensitivity , 2017 .

[17]  Cheolmin Park,et al.  Micropatterned Pyramidal Ionic Gels for Sensing Broad-Range Pressures with High Sensitivity. , 2017, ACS applied materials & interfaces.

[18]  Caofeng Pan,et al.  Full Dynamic‐Range Pressure Sensor Matrix Based on Optical and Electrical Dual‐Mode Sensing , 2017, Advanced materials.

[19]  Bing-xin Wang,et al.  Lignin-based highly sensitive flexible pressure sensor for wearable electronics , 2018 .

[20]  T. Someya,et al.  A Highly Sensitive Capacitive-type Strain Sensor Using Wrinkled Ultrathin Gold Films. , 2018, Nano letters (Print).

[21]  Milin Zhang,et al.  Tilted Pillars on Wrinkled Elastomers as a Reversibly Tunable Optical Window , 2014, Advanced materials.

[22]  S. Jung,et al.  Photo-induced fabrication of Ag nanowire circuitry for invisible, ultrathin, conformable pressure sensors , 2017 .

[23]  Zhanhu Guo,et al.  Flexible polydimethylsiloxane/multi-walled carbon nanotubes membranous metacomposites with negative permittivity , 2017 .

[24]  Moon Kyu Kwak,et al.  Stretchable, adhesion-tunable dry adhesive by surface wrinkling. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[25]  Heung Cho Ko,et al.  Secondary Sensitivity Control of Silver-Nanowire-Based Resistive-Type Strain Sensors by Geometric Modulation of the Elastomer Substrate. , 2017, Small.

[26]  Sung Youb Kim,et al.  Tactile-direction-sensitive and stretchable electronic skins based on human-skin-inspired interlocked microstructures. , 2014, ACS nano.

[27]  Zhong Lin Wang,et al.  Skin-inspired highly stretchable and conformable matrix networks for multifunctional sensing , 2018, Nature Communications.

[28]  Yonggang Huang,et al.  High performance piezoelectric devices based on aligned arrays of nanofibers of poly(vinylidenefluoride-co-trifluoroethylene) , 2013, Nature Communications.

[29]  Lain-Jong Li,et al.  Highly flexible MoS2 thin-film transistors with ion gel dielectrics. , 2012, Nano letters.

[30]  Nae-Eung Lee,et al.  An All‐Elastomeric Transparent and Stretchable Temperature Sensor for Body‐Attachable Wearable Electronics , 2016, Advanced materials.

[31]  Seunghoe Kim,et al.  Highly Sensitive Multifilament Fiber Strain Sensors with Ultrabroad Sensing Range for Textile Electronics. , 2018, ACS nano.

[32]  M. Sitti,et al.  Bioinspired Composite Microfibers for Skin Adhesion and Signal Amplification of Wearable Sensors , 2017, Advanced materials.

[33]  Insol Hwang,et al.  Wet‐Responsive, Reconfigurable, and Biocompatible Hydrogel Adhesive Films for Transfer Printing of Nanomembranes , 2018 .

[34]  J. Simmons Electric Tunnel Effect between Dissimilar Electrodes Separated by a Thin Insulating Film , 1963 .

[35]  Sangwoo Jin,et al.  Stretchable Array of Highly Sensitive Pressure Sensors Consisting of Polyaniline Nanofibers and Au-Coated Polydimethylsiloxane Micropillars. , 2015, ACS nano.

[36]  Ning Wang,et al.  All‐Carbon‐Electrode‐Based Endurable Flexible Perovskite Solar Cells , 2018 .

[37]  Chanseok Lee,et al.  Ultrasensitive mechanical crack-based sensor inspired by the spider sensory system , 2014, Nature.

[38]  Zhenan Bao,et al.  A stretchable and biodegradable strain and pressure sensor for orthopaedic application , 2018 .

[39]  Yi Yang,et al.  Epidermis Microstructure Inspired Graphene Pressure Sensor with Random Distributed Spinosum for High Sensitivity and Large Linearity. , 2018, ACS nano.

[40]  DaeEun Kim,et al.  Rough-Surface-Enabled Capacitive Pressure Sensors with 3D Touch Capability. , 2017, Small.

[41]  Changyu Shen,et al.  Interfacial interaction enhancement by shear-induced β-cylindrite in isotactic polypropylene/glass fiber composites , 2016 .

[42]  Hongwoo Jang,et al.  Low-cost, μm-thick, tape-free electronic tattoo sensors with minimized motion and sweat artifacts , 2018, npj Flexible Electronics.

[43]  Yan Wang,et al.  Liquid-Wetting-Solid Strategy To Fabricate Stretchable Sensors for Human-Motion Detection , 2016 .

[44]  Lim Wei Yap,et al.  Percolating Network of Ultrathin Gold Nanowires and Silver Nanowires toward “Invisible” Wearable Sensors for Detecting Emotional Expression and Apexcardiogram , 2017 .

[45]  R. Dauskardt,et al.  An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film , 2014, Nature Communications.

[46]  Sung Youb Kim,et al.  Giant tunneling piezoresistance of composite elastomers with interlocked microdome arrays for ultrasensitive and multimodal electronic skins. , 2014, ACS nano.

[47]  B. Shirinzadeh,et al.  A wearable and highly sensitive pressure sensor with ultrathin gold nanowires , 2014, Nature Communications.

[48]  Bo Liedberg,et al.  Surface Strain Redistribution on Structured Microfibers to Enhance Sensitivity of Fiber‐Shaped Stretchable Strain Sensors , 2018, Advanced materials.

[49]  Minsu Kang,et al.  Multifunctional Smart Skin Adhesive Patches for Advanced Health Care , 2018, Advanced healthcare materials.

[50]  Jonghwa Park,et al.  Bioinspired Interlocked and Hierarchical Design of ZnO Nanowire Arrays for Static and Dynamic Pressure‐Sensitive Electronic Skins , 2015 .

[51]  Zhanhu Guo,et al.  Enhanced electrical conductivity and piezoresistive sensing in multi-wall carbon nanotubes/polydimethylsiloxane nanocomposites via the construction of a self-segregated structure. , 2017, Nanoscale.

[52]  Caofeng Pan,et al.  Self-powered Real-time Movement Monitoring Sensor Using Triboelectric Nanogenerator Technology , 2017, Scientific Reports.

[53]  G. Song,et al.  Determinant role of tunneling resistance in electrical conductivity of polymer composites reinforced by well dispersed carbon nanotubes , 2010 .

[54]  Youngjin Jeong,et al.  Highly Sensitive and Multimodal All‐Carbon Skin Sensors Capable of Simultaneously Detecting Tactile and Biological Stimuli , 2015, Advanced materials.

[55]  I. Park,et al.  Stretchable, Skin‐Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review , 2016 .

[56]  Youngoh Lee,et al.  Ultrasensitive Piezoresistive Pressure Sensors Based on Interlocked Micropillar Arrays , 2014 .

[57]  Zhe Yin,et al.  Flexible and Highly Sensitive Pressure Sensors Based on Bionic Hierarchical Structures , 2017 .

[58]  Wenlong Cheng,et al.  Skin inspired fractal strain sensors using a copper nanowire and graphite microflake hybrid conductive network. , 2016, Nanoscale.

[59]  Sung-hoon Ahn,et al.  A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres. , 2012, Nature materials.

[60]  Yonggang Huang,et al.  Multifunctional Epidermal Electronics Printed Directly Onto the Skin , 2013, Advanced materials.

[61]  Benjamin C. K. Tee,et al.  Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring , 2013, Nature Communications.

[62]  Jong-Hyun Ahn,et al.  Efficient Direct Reduction of Graphene Oxide by Silicon Substrate , 2015, Scientific Reports.