Development of a Highly Sensitive, Broad-Range Hierarchically Structured Reduced Graphene Oxide/PolyHIPE Foam for Pressure Sensing.

Highly sensitive pressure sensors are usually made from soft materials that allow large deformations to be obtained when very small pressures are applied. Unfortunately, this current paradigm limits the ability to create sensors capable of high sensitivities and broad dynamic ranges as these materials are prone to saturation responses when attempting to obtain measurements involving high pressures. In this paper, we detail a piezoresistive pressure sensor that is capable of high sensitivity over a pressure range spanning from 0.6 Pa (a mosquito touching a surface) to 200 kPa (an elephant standing on the surface). The sensor's ability to cover such a broad dynamic range is made possible by the fairly hard foam used in its construction as this material is capable of propagating strain in a highly effective manner due to its hierarchical porous structure. The material was fabricated by using high-internal-phase emulsion (HIPE) as a template to generate a highly porous material consisting of small pores packed between larger ones whose inner walls are lined with reduced graphene oxide. The developed foam exhibits very fast response times (less than 15.4 ms) and excellent cyclic stability (at least 10,000 cycles). Furthermore, it is capable of responding to the entire tactile pressure range, and it can be formatted as pixelated arrays, which makes it highly suitable for integration into wearable electronic devices. Such arrays were built and used to identify and render the shape of objects with different geometries, including a sphere, a triangle, a square, and two nearly identical rods differing only by 0.4 mm in diameter.

[1]  J. Rogers,et al.  Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy. , 2011, Nature materials.

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

[3]  Brian Litt,et al.  Flexible, Foldable, Actively Multiplexed, High-Density Electrode Array for Mapping Brain Activity in vivo , 2011, Nature Neuroscience.

[4]  Zhenan Bao,et al.  Skin-inspired electronic devices , 2014 .

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

[6]  Caofeng Pan,et al.  Enhancing Light Emission of ZnO‐Nanofilm/Si‐Micropillar Heterostructure Arrays by Piezo‐Phototronic Effect , 2015, Advanced materials.

[7]  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.

[8]  Elgar Fleisch,et al.  Flexible-foam-based capacitive sensor arrays for object detection at low cost , 2008 .

[9]  Andrew G. Gillies,et al.  Nanowire active-matrix circuitry for low-voltage macroscale artificial skin. , 2010, Nature materials.

[10]  R. Lakes.  Materials with structural hierarchy , 1993, Nature.

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

[12]  Alex Chortos,et al.  A Sensitive and Biodegradable Pressure Sensor Array for Cardiovascular Monitoring , 2015, Advanced materials.

[13]  Caofeng Pan,et al.  Piezo‐Phototronic Enhanced UV Sensing Based on a Nanowire Photodetector Array , 2015, Advanced materials.

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

[15]  Yichun Ding,et al.  Flexible and Compressible PEDOT:PSS@Melamine Conductive Sponge Prepared via One-Step Dip Coating as Piezoresistive Pressure Sensor for Human Motion Detection. , 2018, ACS applied materials & interfaces.

[16]  T. Trung,et al.  Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human‐Activity Monitoringand Personal Healthcare , 2016, Advanced materials.

[17]  Jing Li,et al.  A linear and large-range pressure sensor based on a graphene/silver nanowires nanobiocomposites network and a hierarchical structural sponge , 2018 .

[18]  Takao Someya,et al.  A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[19]  Ja Hoon Koo,et al.  Highly Skin‐Conformal Microhairy Sensor for Pulse Signal Amplification , 2014, Advanced materials.

[20]  Lim Wei Yap,et al.  Manufacturable conducting rubber ambers and stretchable conductors from copper nanowire aerogel monoliths. , 2014, ACS nano.

[21]  Zhiqiang Wang,et al.  Environment-Friendly Method To Produce Graphene That Employs Vitamin C and Amino Acid , 2010 .

[22]  Hongwei Zhu,et al.  Recent advances in wearable tactile sensors: Materials, sensing mechanisms, and device performance , 2017 .

[23]  Zhiqiang Niu,et al.  High-performance and tailorable pressure sensor based on ultrathin conductive polymer film. , 2014, Small.

[24]  F. Huo,et al.  Microstructured graphene arrays for highly sensitive flexible tactile sensors. , 2014, Small.

[25]  Qiangqiang Zhao,et al.  One-Pot Preparation of Porous Piezoresistive Sensor with High Strain Sensitivity via Emulsion-Templated Polymerization , 2017 .

[26]  Zhengguang Zou,et al.  Piezoresistive Sensor with High Elasticity Based on 3D Hybrid Network of Sponge@CNTs@Ag NPs. , 2016, ACS applied materials & interfaces.

[27]  Zhong Lin Wang,et al.  Taxel-Addressable Matrix of Vertical-Nanowire Piezotronic Transistors for Active and Adaptive Tactile Imaging , 2013, Science.

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

[29]  Dong Jun Lee,et al.  Transparent and Stretchable Interactive Human Machine Interface Based on Patterned Graphene Heterostructures , 2015 .

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

[31]  Lim Wei Yap,et al.  Mimosa-inspired design of a flexible pressure sensor with touch sensitivity. , 2015, Small.

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

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

[34]  Hongbo Wang,et al.  A Highly Stretchable Nanofiber-Based Electronic Skin with Pressure-, Strain-, and Flexion-Sensitive Properties for Health and Motion Monitoring. , 2017, ACS applied materials & interfaces.

[35]  Xiang-Jie Gao,et al.  One-pot interfacial polymerization to prepare PolyHIPEs with functional surface , 2015, Colloid and Polymer Science.

[36]  Zhong Lin Wang,et al.  Recent Progress in Electronic Skin , 2015, Advanced science.

[37]  Eric V. Eason,et al.  Tunable Flexible Pressure Sensors using Microstructured Elastomer Geometries for Intuitive Electronics , 2014 .

[38]  J. Lai,et al.  Functional Polymers from Novel Carboxyl-Terminated Trithiocarbonates as Highly Efficient RAFT Agents , 2002 .

[39]  A. Bismarck,et al.  Hierarchical polymerized high internal phase emulsions synthesized from surfactant-stabilized emulsion templates. , 2013, Langmuir : the ACS journal of surfaces and colloids.

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

[41]  Hossam Haick,et al.  Autonomous Flexible Sensors for Health Monitoring , 2018, Advanced materials.

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

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

[44]  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 .

[45]  T. Ren,et al.  A Graphene-Based Resistive Pressure Sensor with Record-High Sensitivity in a Wide Pressure Range , 2015, Scientific Reports.

[46]  Benjamin C. K. Tee,et al.  25th Anniversary Article: The Evolution of Electronic Skin (E‐Skin): A Brief History, Design Considerations, and Recent Progress , 2013, Advanced materials.

[47]  Jilin Yu,et al.  Mechanical behavior of open-cell metallic foams with dual-size cellular structure , 2008 .

[48]  Yonggang Huang,et al.  Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow , 2015, Science Advances.

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

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

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

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

[53]  Zhong Lin Wang,et al.  High-resolution electroluminescent imaging of pressure distribution using a piezoelectric nanowire LED array , 2013, Nature Photonics.

[54]  Yei Hwan Jung,et al.  Stretchable silicon nanoribbon electronics for skin prosthesis , 2014, Nature Communications.

[55]  Jonghwa Park,et al.  Flexible Ferroelectric Sensors with Ultrahigh Pressure Sensitivity and Linear Response over Exceptionally Broad Pressure Range. , 2018, ACS nano.

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