Highly stretchable strain sensors based on graphene nanoplatelet-doped ecoflex for biomedical purposes

• Published in: Sensors and actuators. A. Physical. Vol. 353; p. 114249
• Main Authors: del Bosque, Antonio, Sánchez-Romate, Xoan F., Gómez, Alberto, Sánchez, María, Ureña, Alejandro
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16-04-2023
• Subjects: Graphene Nanoplatelets; Human motion monitoring; Nanocomposite; Strain Sensor; Graphene Nanoplatelets; Strain Sensor; Nanocomposite; Human motion monitoring
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2023.114249

Ultrasensitive and highly stretchable strain sensors based on graphene nanoplatelet (GNP) doped Ecoflex are proposed. First, the electrical and electromechanical properties are deeply studied. It has been observed that the electrical conductivity significantly increases with GNP content, indicating that the saturation of the electrical network is not reached, even for the samples with 10 wt. % GNP, confirmed by SEM analysis. Furthermore, the analysis of the electromechanical behavior reveals a very high electrical sensitivity, with a gauge factor (GF) of around 25 at ε = 1 % and 3·104 at ε = 30 % in tensile and around 12 at ε = 1 % and 104 at ε = 30 % in compression. Furthermore, the electrical response was found to be stable under medium and long-term cycling tests, proving the high robustness of the proposed sensors. Finally, several proof-of-concept tests are carried out with the optimized sensor, proving the high applicability of the proposed material as pressure sensors, for breathing and wrist pulse monitoring, where the electromechanical responses in a relaxed or tired state are clearly distinguishable, proving the high potential of the developed sensors for biomedical purposes.
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•Strain sensors based on GNP doped Ecoflex are proposed for pressure, breathing and wrist pulse monitoring.•Ultrahigh sensitivity with GF from 25 to 3·104 in tensile, and 12–104 in compression for ε = 1 % and 30 %, respectively.•Stable electrical response under medium and long-term cycling tests.