Highly flexible and stretchable strain sensors based on conductive whisker carbon nanotube films

• Published in: Carbon (New York) Vol. 176; pp. 139 - 147
• Main Authors: Zhang, Jinling, Wang, Min, Yang, Zhaohui, Zhang, Xiaohua
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.05.2021; Elsevier BV
• Subjects: Carbon; Carbon nanotubes; Conductive network; deformation; Densification; Electric resistance; electrical resistance; High sensitivity; humans; Langmuir-Blodgett films; Mechanical properties; Muscles; Polydimethylsiloxane; Sensitivity; Sensors; Strain sensor; Whisker carbon nanotube; Wide strain sensing range; Conductive network; Whisker carbon nanotube; Strain sensor; High sensitivity; Wide strain sensing range
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2021.01.130

We fabricated a conductive whisker carbon nanotube (CNT) film by a simplified Langmuir−Blodgett method in which loose whisker CNTs (WCNTs) were densified via a capillary-induced compression assisted by a porous sponge. After this densification treatment, WCNTs formed conductive networks. The deformation of WCNT networks can cause a significant resistance change. The electric resistance of conductive WCNT network is highly sensitive to external mechanical stimuli. We developed a flexible and stretchable WCNT-based strain sensor using WCNT film sandwiched between two pieces of elastic polydimethylsiloxane films. This WCNT-based sensor exhibits an extremely high sensitivity (up to a gauge factor of 4839) over a wide strain range, fast response (60 ms), the good stability of mechanical cycling (1000 cycles), and extremely wide response window (it can detect strains as low as 0.05% and up to 420%). The WCNT-based sensing devices are able to monitor human muscle activity ranging from vital signs to high-strain human joint motions due to their high sensitivity and wide strain sensing range. [Display omitted]