Poisson Ratio and Piezoresistive Sensing: A New Route to High‐Performance 3D Flexible and Stretchable Sensors of Multimodal Sensing Capability

The performance of flexible and stretchable sensors relies on the optimization of both the flexible substrate and the sensing element, and their synergistic interactions. Herein, a novel strategy is reported for cost-effective and scalable manufacturing of a new class of porous materials as 3D flexible and stretchable piezoresistive sensors, by assembling carbon nanotubes onto porous substrates of tunable Poisson ratios. It is shown that the piezoresistive sensitivity of the sensors increases as the substrate's Poisson's ratio decreases. Substrates with negative Poisson ratios (auxetic foams) exhibit significantly higher piezoresistive sensitivity, resulting from the coherent mode of deformation of the auxetic foam and enhanced changes of tunneling resistance of the carbon nanotube networks. Compared with conventional foam sensors, the auxetic foam sensor (AFS) with a Poisson's ratio of –0.5 demonstrates a 300% improvement in piezoresistive sensitivity and the gauge factor increases as much as 500%. The AFS has high sensing capability, is extremely robust, and capable of multimodal sensing, such as large deformation sensing, pressure sensing, shear/torsion sensing, and underwater sensing. AFS shows great potential for a broad range of wearable and portable devices applications, which are described by reporting on a series of demonstrations.

[1]  Chuck Zhang,et al.  Preparative Ultracentrifuge Method for Characterization of Carbon Nanotube Dispersions , 2008 .

[2]  N. Hu,et al.  Tunneling effect in a polymer/carbon nanotube nanocompositestrain sensor , 2008 .

[3]  K. Hata,et al.  A stretchable carbon nanotube strain sensor for human-motion detection. , 2011, Nature nanotechnology.

[4]  Yang Liu,et al.  Sensitive, high-strain, high-rate bodily motion sensors based on graphene-rubber composites. , 2014, ACS nano.

[5]  Yan Li,et al.  Low-Temperature CO2-Assisted Assembly of Cyclic Olefin Copolymer Ferroelectrets of High Piezoelectricity and Thermal Stability , 2013 .

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

[7]  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.

[8]  C. Li,et al.  Ultralight, flexible, and fire-resistant carbon nanofiber aerogels from bacterial cellulose. , 2013, Angewandte Chemie.

[9]  R. Sun,et al.  Covalently bonded nitrogen-doped carbon-nanotube-supported Ag hybrid sponges: Synthesis, structure manipulation, and its application for flexible conductors and strain-gauge sensors , 2015 .

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

[11]  Zhong Lin Wang,et al.  Triboelectric active sensor array for self-powered static and dynamic pressure detection and tactile imaging. , 2013, ACS nano.

[12]  R. Baughman,et al.  Negative Poisson's ratios as a common feature of cubic metals , 1998, Nature.

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

[14]  Robin H. A. Ras,et al.  Modifying Native Nanocellulose Aerogels with Carbon Nanotubes for Mechanoresponsive Conductivity and Pressure Sensing , 2013, Advanced materials.

[15]  K. Evans,et al.  Auxetic Materials : Functional Materials and Structures from Lateral Thinking! , 2000 .

[16]  Roderic S. Lakes,et al.  Deformation mechanisms in negative Poisson's ratio materials: structural aspects , 1991 .

[17]  Joseph N. Grima,et al.  Negative Poisson's ratios in tendons: An unexpected mechanical response. , 2015, Acta biomaterialia.

[18]  Ji Hoon Kim,et al.  Reverse‐Micelle‐Induced Porous Pressure‐Sensitive Rubber for Wearable Human–Machine Interfaces , 2014, Advanced materials.

[19]  Steve F. A. Acquah,et al.  Carbon nanotubes on a spider silk scaffold , 2013, Nature Communications.

[20]  Joseph N. Grima,et al.  A novel mechanism for generating auxetic behaviour in reticulated foams: missing rib foam model , 2000 .

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

[22]  US Patent Pending , 2022 .

[23]  Jie Zhang,et al.  Glass Fibers with Carbon Nanotube Networks as Multifunctional Sensors , 2010 .

[24]  T. Ren,et al.  Scalable fabrication of high-performance and flexible graphene strain sensors. , 2014, Nanoscale.

[25]  Jianwen Liu,et al.  Single MWNT‐Glass Fiber as Strain Sensor and Switch , 2011, Advanced materials.

[26]  S. Bauer,et al.  Flexible large area ferroelectret sensors for location sensitive touchpads , 2008 .

[27]  Yang,et al.  Electronic structure of deformed carbon nanotubes , 2000, Physical review letters.

[28]  Amit Kumar,et al.  Ultralight multiwalled carbon nanotube aerogel. , 2010, ACS nano.

[29]  V. Maheshwari,et al.  High-Resolution Thin-Film Device to Sense Texture by Touch , 2006, Science.

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

[31]  Andrew G. Gillies,et al.  Carbon nanotube active-matrix backplanes for conformal electronics and sensors. , 2011, Nano letters.

[32]  Congli He,et al.  Ultra-sensitive strain sensors based on piezoresistive nanographene films , 2012 .

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

[34]  R. Lakes.  Foam Structures with a Negative Poisson's Ratio , 1987, Science.

[35]  M. P. Anantram,et al.  Band-gap change of carbon nanotubes: Effect of small uniaxial and torsional strain , 1999 .

[36]  Seiji Akita,et al.  Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors. , 2014, ACS nano.

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

[38]  Chuck Zhang,et al.  Processing and modeling of conductive thermoplastic/carbon nanotube films for strain sensing , 2008 .

[39]  N. Hu,et al.  Investigation on sensitivity of a polymer/carbon nanotube composite strain sensor , 2010 .

[40]  Zhenan Bao,et al.  Material and device considerations for organic thin-film transistor sensors , 2009 .

[41]  Jun Zhou,et al.  High‐Strain Sensors Based on ZnO Nanowire/Polystyrene Hybridized Flexible Films , 2011, Advanced materials.

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

[43]  R. Lakes,et al.  Poisson's ratio and modern materials , 2011, Nature Materials.

[44]  T. Someya,et al.  Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

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

[46]  J. Parise,et al.  Elasticity of α-Cristobalite: A Silicon Dioxide with a Negative Poisson's Ratio , 1992, Science.

[47]  J. Simmons.  Generalized Formula for the Electric Tunnel Effect between Similar Electrodes Separated by a Thin Insulating Film , 1963 .