1. School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, China 2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China 3. College of Materials Science and Engineering, Chongqing University, Chongqing 400030, China 4. School of Mechatronic Engineering, Southwest Petroleum University, Chengdu 610500, China 5. The Center of Functional Materials for Working Fluids of Oil and Gas Field, Southwest Petroleum University, Chengdu 610500, China
In this work, a high-performance fiber strain sensor is fabricated by constructing a double percolated structure, consisting of carbon nanotube (CNT)/thermoplastic polyurethane (TPU) continuous phase and styrene butadiene styrene (SBS) phase, incompatible with TPU (CNT/TPU@SBS). Compared with other similar fiber strain sensor systems without double percolated structure, the CNT/TPU@SBS sensor achieves a lower percolation threshold (0.38 wt.%) and higher electrical conductivity. The conductivity of 1%-CNT/TPU@SBS (4.12×10−3 S·m−1) is two orders of magnitude higher than that of 1%-CNT/TPU (3.17×10−5 S·m−1) at the same CNT loading of 1 wt.%. Due to double percolated structure, the 1%-CNT/TPU@SBS sensor exhibits a wide strain detection range (0.2%–100%) and an ultra-high sensitivity (maximum gauge factor (GF) is 32411 at 100% strain). Besides, the 1%-CNT/TPU@SBS sensor shows a high linearity (R2 = 0.97) at 0%–20% strain, relatively fast response time (214 ms), and stability (500 loading/unloading cycles). The designed sensor can efficiently monitor physiological signals and movements and identify load distribution after being woven into a sensor array, showing broad application prospects in wearable electronics.
T Wang, Y Zhang, Q Liu, et al.. A self-healable, highly stretchable, and solution processable conductive polymer composite for ultrasensitive strain and pressure sensing. Advanced Functional Materials, 2018, 28(7): 1705551 https://doi.org/10.1002/adfm.201705551
2
L Wang, D Xiang, E Harkin-Jones, et al.. A flexible and multipurpose piezoresistive strain sensor based on carbonized phenol formaldehyde foam for human motion monitoring. Macromolecular Materials and Engineering, 2019, 304(12): 1900492 https://doi.org/10.1002/mame.201900492
3
Y He, D Wu, M Zhou, et al.. Wearable strain sensors based on a porous polydimethylsiloxane hybrid with carbon nanotubes and graphene. ACS Applied Materials & Interfaces, 2021, 13(13): 15572–15583 https://doi.org/10.1021/acsami.0c22823
pmid: 33760608
4
H Zhang, D Liu, J H Lee, et al.. Anisotropic, wrinkled, and crack-bridging structure for ultrasensitive, highly selective multidirectional strain sensors. Nano-Micro Letters, 2021, 13(1): 122 https://doi.org/10.1007/s40820-021-00615-5
pmid: 34138324
5
X Wu, Y Han, X Zhang, et al.. Large-area compliant, low-cost, and versatile pressure-sensing platform based on microcrack-designed carbon black@polyurethane sponge for human-machine interfacing. Advanced Functional Materials, 2016, 26(34): 6246–6256 https://doi.org/10.1002/adfm.201601995
6
Q Chen, D Xiang, L Wang, et al.. Facile fabrication and performance of robust polymer/carbon nanotube coated spandex fibers for strain sensing. Composites Part A: Applied Science and Manufacturing, 2018, 112: 186–196 https://doi.org/10.1016/j.compositesa.2018.06.009
7
Y Wang, Y Jia, Y Zhou, et al.. Ultra-stretchable, sensitive and durable strain sensors based on polydopamine encapsulated carbon nanotubes/elastic bands. Journal of Materials Chemistry C: Materials for Optical and Electronic Devices, 2018, 6(30): 8160–8170 https://doi.org/10.1039/C8TC02702A
8
M Zhang, C Wang, Q Wang, et al.. Sheath‒core graphite/silk fiber made by dry-meyer-rod-coating for wearable strain sensors. ACS Applied Materials & Interfaces, 2016, 8(32): 20894–20899 https://doi.org/10.1021/acsami.6b06984
pmid: 27462991
9
Y Wang, J Hao, Z Huang, et al.. Flexible electrically resistive-type strain sensors based on reduced graphene oxide-decorated electrospun polymer fibrous mats for human motion monitoring. Carbon, 2018, 126: 360–371 https://doi.org/10.1016/j.carbon.2017.10.034
10
L Lan, C Jiang, Y Yao, et al.. A stretchable and conductive fiber for multifunctional sensing and energy harvesting. Nano Energy, 2021, 84: 105954 https://doi.org/10.1016/j.nanoen.2021.105954
11
S Lee, S Shin, S Lee, et al.. Ag nanowire reinforced highly stretchable conductive fibers for wearable electronics. Advanced Functional Materials, 2015, 25(21): 3114–3121 https://doi.org/10.1002/adfm.201500628
12
D Xiang, X Zhang, E Harkin-Jones, et al.. Synergistic effects of hybrid conductive nanofillers on the performance of 3D printed highly elastic strain sensors. Composites Part A: Applied Science and Manufacturing, 2020, 129: 105730 https://doi.org/10.1016/j.compositesa.2019.105730
13
Y Zheng, Y Li, Z Li, et al.. The effect of filler dimensionality on the electromechanical performance of polydimethylsiloxane based conductive nanocomposites for flexible strain sensors. Composites Science and Technology, 2017, 139: 64–73 https://doi.org/10.1016/j.compscitech.2016.12.014
14
G Choi, H Jang, S Oh, et al.. A highly sensitive and stress-direction-recognizing asterisk-shaped carbon nanotube strain sensor. Journal of Materials Chemistry C: Materials for Optical and Electronic Devices, 2019, 7(31): 9504–9512 https://doi.org/10.1039/C9TC02486G
15
J Gao, B Li, X Huang, et al.. Electrically conductive and fluorine free superhydrophobic strain sensors based on SiO2/graphene-decorated electrospun nanofibers for human motion monitoring. Chemical Engineering Journal, 2019, 373: 298–306 https://doi.org/10.1016/j.cej.2019.05.045
16
G Chen, H Wang, R Guo, et al.. Superelastic EGaIn composite fibers sustaining 500% tensile strain with superior electrical conductivity for wearable electronics. ACS Applied Materials & Interfaces, 2020, 12(5): 6112–6118 https://doi.org/10.1021/acsami.9b23083
pmid: 31941273
17
J Gao, L Wang, Z Guo, et al.. Flexible, superhydrophobic, and electrically conductive polymer nanofiber composite for multifunctional sensing applications. Chemical Engineering Journal, 2020, 381: 122778 https://doi.org/10.1016/j.cej.2019.122778
18
S Yu, X Wang, H Xiang, et al.. Superior piezoresistive strain sensing behaviors of carbon nanotubes in one-dimensional polymer fiber structure. Carbon, 2018, 140: 1–9 https://doi.org/10.1016/j.carbon.2018.08.028
19
S Yu, X Wang, H Xiang, et al.. 1-D polymer ternary composites: Understanding materials interaction, percolation behaviors and mechanism toward ultra-high stretchable and super-sensitive strain sensors. Science China: Materials, 2019, 62(7): 995–1004 https://doi.org/10.1007/s40843-018-9402-1
20
Y F Chen, J Li, Y J Tan, et al.. Achieving highly electrical conductivity and piezoresistive sensitivity in polydimethylsiloxane/multi-walled carbon nanotube composites via the incorporation of silicon dioxide micro-particles. Composites Science and Technology, 2019, 177: 41–48 https://doi.org/10.1016/j.compscitech.2019.04.017
21
Y Yang, G Zhao, X Cheng, et al.. Stretchable and healable conductive elastomer based on PEDOT:PSS/natural rubber for self-powered temperature and strain sensing. ACS Applied Materials & Interfaces, 2021, 13(12): 14599–14611 https://doi.org/10.1021/acsami.1c00879
pmid: 33751880
22
R Ma, J Lee, D Choi, et al.. Knitted fabrics made from highly conductive stretchable fibers. Nano Letters, 2014, 14(4): 1944–1951 https://doi.org/10.1021/nl404801t
pmid: 24661242
23
K Qi, Y Zhou, K Ou, et al.. Weavable and stretchable piezoresistive carbon nanotubes-embedded nanofiber sensing yarns for highly sensitive and multimodal wearable textile sensor. Carbon, 2020, 170: 464–476 https://doi.org/10.1016/j.carbon.2020.07.042
24
Y Li, B Zhou, G Zheng, et al.. Continuously prepared highly conductive and stretchable SWNT/MWNT synergistically composited electrospun thermoplastic polyurethane yarns for wearable sensing. Journal of Materials Chemistry C: Materials for Optical and Electronic Devices, 2018, 6(9): 2258–2269 https://doi.org/10.1039/C7TC04959E
25
Y Gao, F Guo, P Cao, et al.. Winding-locked carbon nanotubes/polymer nanofibers helical yarn for ultrastretchable conductor and strain sensor. ACS Nano, 2020, 14(3): 3442–3450 https://doi.org/10.1021/acsnano.9b09533
pmid: 32149493
26
B Li, J Luo, X Huang, et al.. A highly stretchable, super-hydrophobic strain sensor based on polydopamine and graphene reinforced nanofiber composite for human motion monitoring. Composites Part B: Engineering, 2020, 181: 107580 https://doi.org/10.1016/j.compositesb.2019.107580
27
Y Xu, X Xie, H Huang, et al.. Encapsulated core–sheath carbon nanotube–graphene/polyurethane composite fiber for highly stable, stretchable, and sensitive strain sensor. Journal of Materials Science, 2021, 56(3): 2296–2310 https://doi.org/10.1007/s10853-020-05394-9
28
L Wang, Y Chen, L Lin, et al.. Highly stretchable, anti-corrosive and wearable strain sensors based on the PDMS/CNTs decorated elastomer nanofiber composite. Chemical Engineering Journal, 2019, 362: 89–98 https://doi.org/10.1016/j.cej.2019.01.014
29
Z Yang, Z Zhai, Z Song, et al.. Conductive and elastic 3D helical fibers for use in washable and wearable electronics. Advanced Materials, 2020, 32(10): 1907495 https://doi.org/10.1002/adma.201907495
pmid: 31984556
30
Y Hu, T Huang, H Zhang, et al.. Ultrasensitive and wearable carbon hybrid fiber devices as robust intelligent sensors. ACS Applied Materials & Interfaces, 2021, 13(20): 23905–23914 https://doi.org/10.1021/acsami.1c03615
pmid: 33980008
31
X Yue, Y Jia, X Wang, et al.. Highly stretchable and durable fiber-shaped strain sensor with porous core‒sheath structure for human motion monitoring. Composites Science and Technology, 2020, 189(35): 108038 https://doi.org/10.1016/j.compscitech.2020.108038
32
Q Chen, Y Li, D Xiang, et al.. Enhanced strain sensing performance of polymer/carbon nanotube-coated spandex fibers via noncovalent interactions. Macromolecular Materials and Engineering, 2020, 305(2): 1900525 https://doi.org/10.1002/mame.201900525
33
J H Cai, Y F Chen, J Li, et al.. Asymmetric deformation in poly(ethylene-co-1-octene)/multi-walled carbon nanotube composites with glass micro-beads for highly piezoresistive sensitivity. Chemical Engineering Journal, 2019, 370: 176–184 https://doi.org/10.1016/j.cej.2019.03.223
34
J H Cai, J Li, X D Chen, et al.. Multifunctional polydimethylsiloxane foam with multi-walled carbon nanotube and thermo-expandable microsphere for temperature sensing, microwave shielding and piezoresistive sensor. Chemical Engineering Journal, 2020, 393: 124805 https://doi.org/10.1016/j.cej.2020.124805
35
W Liu, Y Yang, M Nie. Constructing a double-percolated conductive network in a carbon nanotube/polymer-based flexible semiconducting composite. Composites Science and Technology, 2018, 154: 45–52 https://doi.org/10.1016/j.compscitech.2017.11.003
36
H Bizhani, V Nayyeri, A Katbab, et al.. Double percolated MWCNTs loaded PC/SAN nanocomposites as an absorbing electromagnetic shield. European Polymer Journal, 2018, 100: 209–218 https://doi.org/10.1016/j.eurpolymj.2018.01.016
37
C Mao, Y Zhu, W Jiang. Design of electrical conductive composites: tuning the morphology to improve the electrical properties of graphene filled immiscible polymer blends. ACS Applied Materials & Interfaces, 2012, 4(10): 5281–5286 https://doi.org/10.1021/am301230q
pmid: 22950786
38
X Zhang, D Xiang, W Zhu, et al.. Flexible and high-performance piezoresistive strain sensors based on carbon nanoparticles@polyurethane sponges. Composites Science and Technology, 2020, 200: 108437 https://doi.org/10.1016/j.compscitech.2020.108437
39
N Singh, G Chand, S Kanagaraj. Investigation of thermal conductivity and viscosity of carbon nanotubes–ethylene glycol nanofluids. Heat Transfer Engineering, 2012, 33(9): 821–827 https://doi.org/10.1080/01457632.2012.646922
40
R Socher, B Krause, M T Müller, et al.. The influence of matrix viscosity on MWCNT dispersion and electrical properties in different thermoplastic nanocomposites. Polymer, 2012, 53(2): 495–504 https://doi.org/10.1016/j.polymer.2011.12.019
41
M Ji, H Deng, D Yan, et al.. Selective localization of multi-walled carbon nanotubes in thermoplastic elastomer blends: an effective method for tunable resistivity–strain sensing behavior. Composites Science and Technology, 2014, 92: 16–26 https://doi.org/10.1016/j.compscitech.2013.11.018
42
S Zhang, H Deng, Q Zhang, et al.. Formation of conductive networks with both segregated and double-percolated characteristic in conductive polymer composites with balanced properties. ACS Applied Materials & Interfaces, 2014, 6(9): 6835–6844 https://doi.org/10.1021/am500651v
pmid: 24745303
43
Z Ma, A Wei, Y Li, et al.. Lightweight, flexible and highly sensitive segregated microcellular nanocomposite piezoresistive sensors for human motion detection. Composites Science and Technology, 2021, 203: 108571 https://doi.org/10.1016/j.compscitech.2020.108571
44
D Xiang, L Wang, Y Tang, et al.. Damage self-sensing behavior of carbon nanofiller reinforced polymer composites with different conductive network structures. Polymer, 2018, 158: 308–319 https://doi.org/10.1016/j.polymer.2018.11.007
45
Y Bao, L Xu, H Pang, et al.. Preparation and properties of carbon black/polymer composites with segregated and double-percolated network structures. Journal of Materials Science, 2013, 48(14): 4892–4898 https://doi.org/10.1007/s10853-013-7269-x
46
Y Chen, Q Yang, Y Huang, et al.. Influence of phase coarsening and filler agglomeration on electrical and rheological properties of MWNTs-filled PP/PMMA composites under annealing. Polymer, 2015, 79: 159–170 https://doi.org/10.1016/j.polymer.2015.10.027
47
Y Wang, L Wang, T Yang, et al.. Wearable and highly sensitive graphene strain sensors for human motion monitoring. Advanced Functional Materials, 2014, 24(29): 4666–4670 https://doi.org/10.1002/adfm.201400379
48
D Xiang, X Zhang, Y Li, et al.. Enhanced performance of 3D printed highly elastic strain sensors of carbon nanotube/thermoplastic polyurethane nanocomposites via non-covalent interactions. Composites Part B: Engineering, 2019, 176: 107250 https://doi.org/10.1016/j.compositesb.2019.107250
