Piezoresistive strain sensor array using polydimethylsiloxane-based conducting nanocomposites for electronic skin application

Yung Sin Chong (Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Sungai Long, Malaysia)
Keat Hoe Yeoh (Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Sungai Long, Malaysia)
Pei Ling Leow (Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Skudai, Johor)
Pei Song Chee (Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Sungai Long, Malaysia)

Sensor Review

ISSN: 0260-2288

Publication date: 17 September 2018

Abstract

Purpose

This paper aims to report a stretchable piezoresistive strain sensor array that can detect various static and dynamic stimuli, including bending, normal force, shear stress and certain range of temperature variation, through sandwiching an array of conductive blocks, made of multiwalled carbon nanotubes (MWCNTs) and polydimethylsiloxane (PDMS) composite. The strain sensor array induces localized resistance changes at different external mechanical forces, which can be potentially implemented as electronic skin.

Design/methodology/approach

The working principle is the piezoresistivity of the strain sensor array is based on the tunnelling resistance connection between the fillers and reformation of the percolating path when the PDMS and MWCNT composite deforms. When an external compression stimulus is exerted, the MWCNT inter-filler distance at the conductive block array reduces, resulting in the reduction of the resistance. The resistance between the conductive blocks in the array, on the other hand, increases when the strain sensor is exposed to an external stretching force. The methodology was as follows: Numerical simulation has been performed to study the pressure distribution across the sensor. This method applies two thin layers of conductive elastomer composite across a 2 × 3 conductive block array, where the former is to detect the stretchable force, whereas the latter is to detect the compression force. The fabrication of the strain sensor consists of two main stages: fabricating the conducting block array (detect compression force) and depositing two thin conductive layers (detect stretchable force).

Findings

Characterizations have been performed at the sensor pressure response: static and dynamic configuration, strain sensing and temperature sensing. Both pressure and strain sensing are studied in terms of the temporal response. The temporal response shows rapid resistance changes and returns to its original value after the external load is removed. The electrical conductivity of the prototype correlates to the temperature by showing negative temperature coefficient material behaviour with the sensitivity of −0.105 MΩ/°C.

Research limitations/implications

The conductive sensor array can potentially be implemented as electronic skin due to its reaction with mechanical stimuli: compression and stretchable pressure force, strain sensing and temperature sensing.

Originality/value

This prototype enables various static and dynamic stimulus detections, including bending, normal force, shear stress and certain range of temperature variation, through sandwiching an array of conductive blocks, made of MWCNT and PDMS composite. Conventional design might need to integrate different microfeatures to perform the similar task, especially for dynamic force sensing.

Keywords

Acknowledgements

The authors would like to acknowledge Universiti Tunku Abdul Rahman Research Fund (UTARRF) (IPSR/RMC/UTARRF/2017-C1/C01, Vote No: 6200/CC8), Research University Grant (Q.J130000.2523.15H88) from Universiti Teknologi Malaysia and Fundamental Research Grant Scheme (FRGS) (R.J130000.7823.4F462 and FRGS/1/2017/STG07/UTAR/02/2).

Citation

Chong, Y.S., Yeoh, K.H., Leow, P.L. and Chee, P.S. (2018), "Piezoresistive strain sensor array using polydimethylsiloxane-based conducting nanocomposites for electronic skin application", Sensor Review, Vol. 38 No. 4, pp. 494-500. https://doi.org/10.1108/SR-11-2017-0238

Download as .RIS

Publisher

:

Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

To read the full version of this content please select one of the options below

You may be able to access this content by logging in via Shibboleth, Open Athens or with your Emerald account.
To rent this content from Deepdyve, please click the button.
If you think you should have access to this content, click the button to contact our support team.