High-Sensitivity GNPs/PDMS Flexible Strain Sensor with a Microdome Array

Abstract

In this research, polydimethylsiloxane (PDMS) and graphene nanoplatelets (GNPs) were used as flexible substrates and conductive layers. A facile and template transfer method combined with a low-cost solution-spraying process was adopted to prepare the microdome array GNPs/PDMS flexible strain sensor. The microdome array produces different degrees of in-plane deformation and the gradient distribution of the GNP conductive network on the surface during stretching. This affects the contact effect between the adjacent cells of the GNP conductive network on the film surface in different strain ranges, thereby realizing a sensitive resistance response. The strain sensor of the microdome array GNPs/PDMS exhibits excellent gauge factors (GF) of 8.98 (0.26% < ε < 20%), 18.31 (20% < ε < 43%), and 34.57 (43% < ε < 60%), the highest of which is 8 times higher than that of the planar GNPs/PDMS strain sensor without a microdome array. In addition, the material exhibits remarkable stability and durability (10 000 cycles), fast response time (125 ms), and stable relative frequency/strain sensing performance. Finally, the strain sensors of the microdome array GNPs/PDMS were packaged for various application tests, showing broad application prospects in electronic skin, wearable electronic devices, and component health monitoring.

Thermoplastic Polyurethane/Carbon Nanotube Composites for Stretchable Flexible Pressure Sensors

“…The microdome array film presents a nonuniform deformation mode during the tensile process, and the nonuniform variation of the distance between conductive networks contributes to a more sensitive resistance response. The working mechanism of strain sensors with a microdome array structure has been elaborated in the previous work …”

“…The working mechanism of strain sensors with a microdome array structure has been elaborated in the previous work. 10 The I−V curves of TPU/CNT strain sensors (M) under different strains are shown in Figure S5. The current increases with the voltage linearly, following Ohm's law.…”

“…In the author’s previous work, the flexible strain sensors with microdome arrays have been successfully prepared. The positive effect of the surface microstructure array on sensor strain sensitivity is analyzed and verified . Based on the superior flexibility of TPU composites, its application in the field of flexible sensing has been researched in ref , , .…”

“…CPCs have the advantages of light quality, easy machining, mass production, and adjustable performance, overcoming the rigidity of traditional rigid metal/inorganic semiconductor sensors. 1,2 CPCs have been demonstrated to possess a vast practical future in areas such as electromagnetic shielding, 3,4 temperature sensing, 1,5,6 gas sensing, 7,8 health monitoring, 9,10 and wearable electronics. 5,11 Currently, carbon nanotubes, 12−14 graphene, 15,16 metal nanowires, 17−19 and MXenes 20,21 have been researched as piezoresistive materials.…”

“…The positive effect of the surface microstructure array on sensor strain sensitivity is analyzed and verified. 10 Based on the superior flexibility of TPU composites, its application in the field of flexible sensing has been researched in ref 31, 49, 50. In this work, the TPU/CNT porous composites with microdome arrays on the surface are prepared based on mold transfer and freeze-drying. A strain and pressure sensor with a wide detection range and high sensitivity response has been formed through different assembly methods.…”