Wearable Resistive Pressure Sensor Based on Highly Flexible Carbon Composite Conductors with Irregular Surface Morphology.

Wearable pressure sensors are crucial building blocks for potential applications in real-time health monitoring, artificial electronic skins, and human-to-machine interfaces. Here we present a highly sensitive, simple-architectured wearable resistive pressure sensor based on highly compliant yet robust carbon composite conductors made of a vertically aligned carbon nanotube (VACNT) forest embedded in a polydimethylsiloxane (PDMS) matrix with irregular surface morphology. A roughened surface of the VACNT/PDMS composite conductor is simply formed using a sandblasted silicon master in a low-cost and potentially scalable manner and plays an important role in improving the sensitivity of resistive pressure sensor. After assembling two of the roughened composite conductors, our sensor shows considerable pressure sensitivity of ∼0.3 kPa-1 up to 0.7 kPa as well as stable steady-state responses under various pressures, a wide detectable range of up to 5 kPa before saturation, a relatively fast response time of ∼162 ms, and good reproducibility over 5000 cycles of pressure loading/unloading. The fabricated pressure sensor can be used to detect a wide range of human motions ranging from subtle blood pulses to dynamic joint movements, and it can also be used to map spatial pressure distribution in a multipixel platform (in a 4 × 4 pixel array).

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

[2]  Xiaojun Guo,et al.  Large Area One-Step Facile Processing of Microstructured Elastomeric Dielectric Film for High Sensitivity and Durable Sensing over Wide Pressure Range. , 2016, ACS applied materials & interfaces.

[3]  Adrian J. Y. Chee,et al.  High Sensitivity, Wearable, Piezoresistive Pressure Sensors Based on Irregular Microhump Structures and Its Applications in Body Motion Sensing. , 2016, Small.

[4]  W. Nichols.  Clinical measurement of arterial stiffness obtained from noninvasive pressure waveforms. , 2005, American journal of hypertension.

[5]  S. Yao,et al.  Wearable multifunctional sensors using printed stretchable conductors made of silver nanowires. , 2014, Nanoscale.

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

[7]  Dong-Wook Jeong,et al.  Stable hierarchical superhydrophobic surfaces based on vertically aligned carbon nanotube forests modified with conformal silicone coating , 2014 .

[8]  Yanlong Tai,et al.  Flexible pressure sensing film based on ultra-sensitive SWCNT/PDMS spheres for monitoring human pulse signals. , 2015, Journal of materials chemistry. B.

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

[10]  Gilles Lubineau,et al.  A highly sensitive, low-cost, wearable pressure sensor based on conductive hydrogel spheres. , 2015, Nanoscale.

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

[12]  Yonggang Huang,et al.  Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring , 2014, Nature Communications.

[13]  Wenping Hu,et al.  Solution-Processed Large-Area Nanocrystal Arrays of Metal-Organic Frameworks as Wearable, Ultrasensitive, Electronic Skin for Health Monitoring. , 2015, Small.

[14]  Inkyu Park,et al.  Highly Sensitive, Flexible, and Wearable Pressure Sensor Based on a Giant Piezocapacitive Effect of Three-Dimensional Microporous Elastomeric Dielectric Layer. , 2016, ACS applied materials & interfaces.

[15]  Yaping Zang,et al.  Advances of flexible pressure sensors toward artificial intelligence and health care applications , 2015 .

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

[17]  Benjamin C. K. Tee,et al.  Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. , 2011, Nature nanotechnology.

[18]  Dong-Wook Jeong,et al.  Highly stretchable conductors and piezocapacitive strain gauges based on simple contact-transfer patterning of carbon nanotube forests , 2014 .

[19]  Jaebeom Lee,et al.  Metal nanowire percolation micro-grids embedded in elastomers for stretchable and transparent conductors , 2015 .

[20]  U. Chung,et al.  Highly Stretchable Resistive Pressure Sensors Using a Conductive Elastomeric Composite on a Micropyramid Array , 2014, Advanced materials.

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

[22]  Shuhong Yu,et al.  A Flexible and Highly Pressure‐Sensitive Graphene–Polyurethane Sponge Based on Fractured Microstructure Design , 2013, Advanced materials.

[23]  Katsuhiko Kohara,et al.  Radial augmentation index: a useful and easily obtainable parameter for vascular aging. , 2004, American journal of hypertension.

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

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

[26]  J. Tour,et al.  Rational design of hybrid graphene films for high-performance transparent electrodes. , 2011, ACS nano.

[27]  Xuewen Wang,et al.  Silk‐Molded Flexible, Ultrasensitive, and Highly Stable Electronic Skin for Monitoring Human Physiological Signals , 2014, Advanced materials.

[28]  Sunwoo Woo,et al.  A thin all-elastomeric capacitive pressure sensor array based on micro-contact printed elastic conductors , 2014 .

[29]  Chunya Wang,et al.  Carbonized Silk Nanofiber Membrane for Transparent and Sensitive Electronic Skin , 2017 .

[30]  Canhui Lu,et al.  Large‐Area Compliant, Low‐Cost, and Versatile Pressure‐Sensing Platform Based on Microcrack‐Designed Carbon Black@Polyurethane Sponge for Human–Machine Interfacing , 2016 .