SCIENCE CHINA Materials, Volume 62, Issue 4: 555-565(2019) https://doi.org/10.1007/s40843-018-9348-8

Stretchable and multifunctional strain sensors based on 3D graphene foams for active and adaptive tactile imaging

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  • ReceivedJun 23, 2018
  • AcceptedSep 1, 2018
  • PublishedSep 25, 2018


The highly developed flexible electronics puts forward higher requirements for the stretchable strain sensors with excellent multiple performances. Herein, a simple and economical fabrication strategy is adopted to obtain a new strain sensor based on Ecoflex rubbers, three-dimensional (3D) graphene foams (GrF) and modified silicone rubber (MSR). The device possesses high stretchability (tolerable strain up to 100%) with a variety of capabilities, such as pressure and strain sensing, strain visualization and strain-controlled heating. The GrF with excellent electrical property and MSR with ideal mechanical property endow the sensor with a wide sensing range (up to 100% strain and 66 kPa stress), high sensitivity (gauge factor of 584.2 within the strain range of 80%–100% and sensitivity of 0.183 kPa−1 in 5–10 kPa) and long cycle life (more than 10,000 cycles) for pressure/strain sensing. In addition, the temperature of the device can be increased 35°C in 5 min under 5 V. Based on this, the deformation is visible to the naked eyes by the color conversion of thermochromic MSR. The soft and reversible strain sensor can be served as the electronic skin (e-skin) for real-time and high accuracy detecting of electrophysiological stimuli, a wearable heater for thermotherapy or body warming and even intelligent visual-touch panel.

Funded by

the National Natural Science Foundation of China(51572025)

the National Foundation of China(41422050303)

the Program of Introducing Talents of Discipline to Universities(B14003)

Beijing Municipal Science & Technology Commission and the Fundamental Research Funds for Central Universities.


This work was supported by the National Natural Science Foundation of China (51572025), the National Foundation of China (41422050303), the Program of Introducing Talents of Discipline to Universities (B14003), Beijing Municipal Science &Technology Commission and the Fundamental Research Funds for Central Universities.

Interest statement

The authors declare no conflict of interest.

Contributions statement

The manuscript was written by Xu M with support from all authors. All authors have given approval to the final version of the manuscript.

Author information

Minxuan Xu received her PhD degree from the Department of Materials Science, University of Science & Technology Beijing in 2018. She joined the School of Materials and Environmental Engineering at Hangzhou Dianzi University, China as a lecturer in 2018. Her current research focuses on materials and devices for flexible and smart electronics.

Junjie Qi is a full Professor of the University of Science & Technology Beijing, China. She received her PhD degree from the Department of Materials Science at University of Science & Technology Beijing in 2002. She has published more than 100 peer review papers. Her current research interest includes the semiconductor nanomaterials, electronic/opto-electronics and the devices of low-dimensional materials.


Supplementary information

Experimental details and supplementary data are available in the online version of the paper.


[1] Jian M, Wang C, Wang Q, et al. Advanced carbon materials for flexible and wearable sensors. Sci China Mater, 2017, 60: 1026-1062 CrossRef Google Scholar

[2] Liu Y, He K, Chen G, et al. Nature-inspired structural materials for flexible electronic devices. Chem Rev, 2017, 117: 12893-12941 CrossRef PubMed Google Scholar

[3] Luo CS, Wan P, Yang H, et al. Healable transparent electronic devices. Adv Funct Mater, 2017, 27: 1606339 CrossRef Google Scholar

[4] Qi J, Lan YW, Stieg AZ, et al. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics. Nat Commun, 2015, 6: 7430 CrossRef PubMed ADS Google Scholar

[5] Lipomi DJ, Vosgueritchian M, Tee BCK, et al. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes. Nat Nanotechnol, 2011, 6: 788-792 CrossRef PubMed ADS Google Scholar

[6] Pan L, Chortos A, Yu G, et al. An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film. Nat Commun, 2014, 5: 3002 CrossRef PubMed ADS Google Scholar

[7] Huang YA, Ding Y, Bian J, et al. Hyper-stretchable self-powered sensors based on electrohydrodynamically printed, self-similar piezoelectric nano/microfibers. Nano Energy, 2017, 40: 432-439 CrossRef Google Scholar

[8] Wang T, Yang H, Qi D, et al. Mechano-based transductive sensing for wearable healthcare. Small, 2018, 14: 1702933 CrossRef PubMed Google Scholar

[9] Yao S, Zhu Y. Wearable multifunctional sensors using printed stretchable conductors made of silver nanowires. Nanoscale, 2014, 6: 2345-2352 CrossRef PubMed ADS Google Scholar

[10] Lee J, Kwon H, Seo J, et al. Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics. Adv Mater, 2015, 27: 2433-2439 CrossRef PubMed Google Scholar

[11] Wu JJ, Chen CX, Ma TH, et al. Edge effect analysis of capacitive grid sensor based on ansoft. Instrument Technique and Sensor, 2016, 2: 1–4. Google Scholar

[12] Wang X, Dong L, Zhang H, et al. Recent progress in electronic skin. Adv Sci, 2015, 2: 1500169 CrossRef PubMed Google Scholar

[13] Jian M, Xia K, Wang Q, et al. Flexible and highly sensitive pressure sensors based on bionic hierarchical structures. Adv Funct Mater, 2017, 27: 1606066 CrossRef Google Scholar

[14] Wang Q, Jian M, Wang C, et al. Carbonized silk nanofiber membrane for transparent and sensitive electronic skin. Adv Funct Mater, 2017, 27: 1605657 CrossRef Google Scholar

[15] Xia K, Wang C, Jian M, et al. CVD growth of fingerprint-like patterned 3D graphene film for an ultrasensitive pressure sensor. Nano Res, 2018, 11: 1124-1134 CrossRef Google Scholar

[16] Liao X, Zhang Z, Kang Z, et al. Ultrasensitive and stretchable resistive strain sensors designed for wearable electronics. Mater Horiz, 2017, 4: 502-510 CrossRef Google Scholar

[17] Wang C, Xia K, Zhang M, et al. An all-silk-derived dual-mode e-skin for simultaneous temperature–pressure detection. ACS Appl Mater Interfaces, 2017, 9: 39484-39492 CrossRef Google Scholar

[18] Wang C, Xia K, Jian M, et al. Carbonized silk georgette as an ultrasensitive wearable strain sensor for full-range human activity monitoring. J Mater Chem C, 2017, 5: 7604-7611 CrossRef Google Scholar

[19] Wang C, Li X, Gao E, et al. Carbonized silk fabric for ultrastretchable, highly sensitive, and wearable strain sensors. Adv Mater, 2016, 28: 6640-6648 CrossRef PubMed Google Scholar

[20] Xu M, Qi J, Li F, et al. Highly stretchable strain sensors with reduced graphene oxide sensing liquids for wearable electronics. Nanoscale, 2018, 10: 5264-5271 CrossRef PubMed Google Scholar

[21] Trung TQ, Lee NE. Flexible and stretchable physical sensor integrated platforms for wearable human-activity monitoringand personal healthcare. Adv Mater, 2016, 28: 4338-4372 CrossRef PubMed Google Scholar

[22] Liao X, Liao Q, Zhang Z, et al. A highly stretchable ZnO@fiber-based multifunctional nanosensor for strain/temperature/UV detection. Adv Funct Mater, 2016, 26: 3074-3081 CrossRef Google Scholar

[23] Xu H, Xiang JX, Lu YF, et al. Multifunctional wearable sensing devices based on functionalized graphene films for simultaneous monitoring of physiological signals and volatile organic compound biomarkers. ACS Appl Mater Interfaces, 2018, 10: 11785-11793 CrossRef Google Scholar

[24] Hua Q, Sun J, Liu H, et al. Skin-inspired highly stretchable and conformable matrix networks for multifunctional sensing. Nat Commun, 2018, 9: 244 CrossRef PubMed ADS Google Scholar

[25] Kudin KN, Ozbas B, Schniepp HC, et al. Raman spectra of graphite oxide and functionalized graphene sheets. Nano Lett, 2008, 8: 36-41 CrossRef PubMed ADS Google Scholar

[26] Çelik Y, Flahaut E, Suvacı E. A comparative study on few-layer graphene production by exfoliation of different starting materials in a low boiling point solvent. FlatChem, 2017, 1: 74-88 CrossRef Google Scholar

[27] Embrey L, Nautiyal P, Loganathan A, et al. Three-dimensional graphene foam induces multifunctionality in epoxy nanocomposites by simultaneous improvement in mechanical, thermal, and electrical properties. ACS Appl Mater Interfaces, 2017, 9: 39717-39727 CrossRef Google Scholar

[28] Jeong YR, Park H, Jin SW, et al. Highly stretchable and sensitive strain sensors using fragmentized graphene foam. Adv Funct Mater, 2015, 25: 4228-4236 CrossRef Google Scholar

[29] He W, Li G, Zhang S, et al. Polypyrrole/silver coaxial nanowire aero-sponges for temperature-independent stress sensing and stress-triggered Joule heating. ACS Nano, 2015, 9: 4244-4251 CrossRef Google Scholar

[30] Qin Y, Peng Q, Ding Y, et al. Lightweight, superelastic, and mechanically flexible graphene/polyimide nanocomposite foam for strain sensor application. ACS Nano, 2015, 9: 8933-8941 CrossRef Google Scholar

[31] Wang X, Gu Y, Xiong Z, et al. Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals. Adv Mater, 2014, 26: 1336-1342 CrossRef PubMed Google Scholar

[32] Tewari A, Gandla S, Bohm S, et al. Highly exfoliated MWNT–rGO ink-wrapped polyurethane foam for piezoresistive pressure sensor applications. ACS Appl Mater Interfaces, 2018, 10: 5185-5195 CrossRef Google Scholar

[33] Yamada T, Hayamizu Y, Yamamoto Y, et al. A stretchable carbon nanotube strain sensor for human-motion detection. Nat Nanotechnol, 2011, 6: 296-301 CrossRef PubMed ADS Google Scholar

[34] Nieto A, Boesl B, Agarwal A. Multi-scale intrinsic deformation mechanisms of 3D graphene foam. Carbon, 2015, 85: 299-308 CrossRef Google Scholar

[35] Nautiyal P, Boesl B, Agarwal A. The mechanics of energy dissipation in a three-dimensional graphene foam with macroporous architecture. Carbon, 2018, 132: 59-64 CrossRef Google Scholar

[36] Bustillos J, Zhang C, Boesl B, et al. Three-dimensional graphene foam–polymer composite with superior deicing efficiency and strength. ACS Appl Mater Interfaces, 2018, 10: 5022-5029 CrossRef Google Scholar

[37] Samad YA, Li Y, Schiffer A, et al. Graphene foam developed with a novel two-step technique for low and high strains and pressure-sensing applications. Small, 2015, 11: 2380-2385 CrossRef PubMed Google Scholar

[38] Boland CS, Khan U, Backes C, et al. Sensitive, high-strain, high-rate bodily motion sensors based on graphene–rubber composites. ACS Nano, 2014, 8: 8819-8830 CrossRef PubMed Google Scholar

[39] Wilde AAM. Proposed diagnostic criteria for the Brugada syndrome: consensus report. Circulation, 2002, 106: 2514-2519 CrossRef Google Scholar

[40] Xu R, Lu Y, Jiang C, et al. Facile fabrication of three-dimensional graphene foam/poly(dimethylsiloxane) composites and their potential application as strain sensor. ACS Appl Mater Interfaces, 2014, 6: 13455-13460 CrossRef PubMed Google Scholar

[41] Zhang M, Wang C, Liang X, et al. Weft-knitted fabric for a highly stretchable and low-voltage wearable heater. Adv Electron Mater, 2017, 3: 1700193 CrossRef Google Scholar

  • Figure 1

    Preparation and characterization of the stretchable strain sensor based on MSR/GrF/Ecoflex composite. (a) Schematic illustration of the strain sensor. (b) Photograph of a torsional strain sensor. (c) Raman shift of pure Ecoflex, pure GrF before and after etching, and the composite of the two. (d) Optical image of the cross-section of the strain sensor. (e) SEM image of the GrF after etching. (f) SEM image of the upper MSR layer.

  • Figure 2

    Application of the multifunctional device as compressive stress detection. (a) Current-voltage of the strain sensor under different applied pressure. (b) Sensitivities of strain sensor during the pressure from 0 to 40 kPa. (c) Multiple-cycle tests of change in resistance with different applied pressure. (d) Real-time fast response and release of the strain sensor upon 9 kPa pressure. (e) Cycling stability test of strain sensor under repeated applied pressure of 9 kPa for 10,000 cycles (1.2 s for each cycle).

  • Figure 3

    Application of the multifunctional device as tensile strain detection. (a) Typical relative resistance-strain curve of a strain sensor within 100% strain; the inset shows the curve within 60% strain. (b) The time-resistance curves for repeated step-by-step stretching at different rates. (c) Variation of the resistance of the MSR/GrF/Ecoflex composite with the strain of 10% under different strain rates from 180% min−1 to 450% min−1. (d) Reliability test of the sensor under repeated cycles of stretching and releasing at different values with partial enlarged details in insets. (e) Recognition of three songs (60 dB) played by mobile phone for the strain sensor (the green curves in the background panels are the sound wave profiles). (f) Zoomed signals of the sensor corresponding to the same vibration audio at different decibels (60, 80, and 100 dB).

  • Figure 4

    Application of the multifunctional device in human motion detection. (a) Real-time and in situ AWPs measurement with the skin-attachable strain sensor attached on the wrist. The inset shows the zoomed waveform. (b) Measurement of JVPs with strain sensors attached on the neck. The inset is the zoomed waveform. (c) Relative resistance changes versus time for the strain sensor during breathing. (d) Relative resistance changes versus time for the strain sensor during saliva swallowing.

  • Figure 5

    Application of the multifunctional device in strain-controlled heater. (a) Schematic of measurement setup. (b) Relative electrical resistance of the strain sensor and temperature curve with time. (c) Heating behavior of the MSR/GrF/Ecoflex composite under various working voltages (the inset is the photographs). (d) Temperature-time curves of the MSR/GrF/Ecoflex composite under various strain states.

  • Figure 6

    Application of the multifunctional device in strain visualization. (a) Real-time temperature changes corresponding to various applied strains, each maintained for 5 min. (b) The strain distribution for “Loading” and “Unloading” compress applied of balls with different position. (c) Relative resistance changes for the stretchable panel in writing process of “USTB”. (d) Relative resistance changes for the stretchable panel in writing process of “NANO”. The insets are the photographs, respectively.

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