Multidirectional flexible force sensors based on confined, self-adjusting carbon nanotube arrays

We demonstrate a highly sensitive force sensor based on self-adjusting carbon nanotube (CNT) arrays. Aligned CNT arrays are directly synthesized on silicon microstructures by a space-confined growth technique which enables a facile self-adjusting contact. To afford flexibility and softness, the patterned microstructures with the integrated CNTs are embedded in polydimethylsiloxane structures. The sensing mechanism is based on variations in the contact resistance between the facing CNT arrays under the applied force. By finite element analysis, proper dimensions and positions for each component are determined. Further, high sensitivities up to 15.05%/mN of the proposed sensors were confirmed experimentally. Multidirectional sensing capability could also be achieved by designing multiple sets of sensing elements in a single sensor. The sensors show long-term operational stability, owing to the unique properties of the constituent CNTs, such as outstanding mechanical durability and elasticity.

[1]  T. Ebbesen,et al.  Exceptionally high Young's modulus observed for individual carbon nanotubes , 1996, Nature.

[2]  M. Sohgawa,et al.  Fabrication and Characterization of Silicon-Polymer Beam Structures for Cantilever-Type Tactile Sensors , 2007, TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference.

[3]  R. Ruoff,et al.  Strength and breaking mechanism of multiwalled carbon nanotubes under tensile load , 2000, Science.

[4]  C. Hierold,et al.  Nano-electromechanical displacement sensing based on single-walled carbon nanotubes. , 2006, Nano letters.

[5]  C. Hierold.  From micro- to nanosystems: mechanical sensors go nano , 2004 .

[6]  E. Engeberg,et al.  Force and slip detection with direct-write compliant tactile sensors using multi-walled carbon nanotube/polymer composites , 2013 .

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

[8]  Xingzhong Zhao,et al.  Novel ZnO Nanorod Flexible Strain Sensor and Strain Driving Transistor with an Ultrahigh 107 Scale “On”−“Off” Ratio Fabricated by a Single-Step Hydrothermal Reaction , 2011 .

[9]  W. Fang,et al.  Development of patterned carbon nanotubes on a 3D polymer substrate for the flexible tactile sensor application , 2011 .

[10]  Jongbaeg Kim,et al.  Using confined self-adjusting carbon nanotube arrays as high-sensitivity displacement sensing element. , 2014, ACS applied materials & interfaces.

[11]  Yongli Mi,et al.  Micromolding of PDMS scaffolds and microwells for tissue culture and cell patterning: A new method of microfabrication by the self-assembled micropatterns of diblock copolymer micelles , 2006 .

[12]  Kimberly L. Turner,et al.  Direction‐Selective and Length‐Tunable In‐Plane Growth of Carbon Nanotubes , 2003 .

[13]  M. Gijs,et al.  Polymer-based flexible capacitive sensor for three-axial force measurements , 2012 .

[14]  Jongbaeg Kim,et al.  A highly sensitive flexible strain sensor based on the contact resistance change of carbon nanotube bundles , 2016, Nanotechnology.

[15]  Jongbaeg Kim,et al.  Thickness-, alignment- and defect-tunable growth of carbon nanotube arrays using designed mechanical loads , 2014 .

[16]  Y. Yang,et al.  A flexible tactile and shear sensing array fabricated using a novel buckypaper patterning technique , 2015 .

[17]  Hai Zhou,et al.  Electrospun PEDOT:PSS–PVA nanofiber based ultrahigh-strain sensors with controllable electrical conductivity , 2011 .

[18]  S. Pyo,et al.  Development of flexible tactile sensor based on contact resistance of integrated carbon nanotubes , 2013, 2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS).

[19]  Nader Jalili,et al.  Reinforcement of Piezoelectric Polymers with Carbon Nanotubes: Pathway to Next-generation Sensors , 2006 .

[20]  Soo-Chul Lim,et al.  Development of a flexible three-axis tactile sensor based on screen-printed carbon nanotube-polymer composite , 2014 .

[21]  Mostafa Bedewy,et al.  Collective mechanism for the evolution and self-termination of vertically aligned carbon nanotube growth , 2009 .

[22]  Jongbaeg Kim,et al.  Aligned Carbon Nanotube Arrays for Degradation‐Resistant, Intimate Contact in Micromechanical Devices , 2011, Advanced materials.

[23]  Keith J. Rebello,et al.  Applications of MEMS in surgery , 2004, Proceedings of the IEEE.

[24]  R. Superfine,et al.  Bending and buckling of carbon nanotubes under large strain , 1997, Nature.

[25]  Isao Shimoyama,et al.  Three-dimensional integration of heterogeneous silicon micro-structures by liftoff and stamping transfer , 2007 .

[26]  Nigel H. Lovell,et al.  Development of nanoparticle film-based multi-axial tactile sensors for biomedical applications , 2013 .

[27]  A. Mata,et al.  Characterization of Polydimethylsiloxane (PDMS) Properties for Biomedical Micro/Nanosystems , 2005, Biomedical microdevices.

[28]  Hyung-Kew Lee,et al.  Iop Publishing Journal of Micromechanics and Microengineering Real-time Measurement of the Three-axis Contact Force Distribution Using a Flexible Capacitive Polymer Tactile Sensor , 2022 .

[29]  A. Erdman,et al.  Flexible Tactile Sensor for Tissue Elasticity Measurements , 2009, Journal of Microelectromechanical Systems.

[30]  Kaspar Althoefer,et al.  Tactile sensing for dexterous in-hand manipulation in robotics-A review , 2011 .

[31]  M. Strano,et al.  A mechanochemical model of growth termination in vertical carbon nanotube forests. , 2008, ACS nano.

[32]  Martin Buss,et al.  Compliant actuation of rehabilitation robots , 2008, IEEE Robotics & Automation Magazine.

[33]  M. Cullinan,et al.  A multi-axis MEMS sensor with integrated carbon nanotube-based piezoresistors for nanonewton level force metrology , 2012, Nanotechnology.

[34]  E. Hwang,et al.  A Polymer-Based Flexible Tactile Sensor for Both Normal and Shear Load Detections and Its Application for Robotics , 2007, Journal of Microelectromechanical Systems.

[35]  L. Addadi,et al.  Force and focal adhesion assembly: a close relationship studied using elastic micropatterned substrates , 2001, Nature Cell Biology.

[36]  K. Fan,et al.  Fabrication and Characterization of Electro-Active Polymer for Flexible Tactile Sensing Array , 2008 .

[37]  Ming-Yuan Cheng,et al.  A Novel Highly-Twistable Tactile Sensing Array using Extendable Spiral Electrodes , 2009, 2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems.

[38]  Shuo-Hung Chang,et al.  An integrated flexible temperature and tactile sensing array using PI-copper films ☆ , 2008 .

[39]  Weijie Liu,et al.  A new approach for ultrahigh-performance piezoresistive sensor based on wrinkled PPy film with electrospun PVA nanowires as spacer , 2017 .

[40]  Jun Xu,et al.  Contact mechanics and thermal conductance of carbon nanotube array interfaces , 2009 .