Beyond Skin Pressure Sensing: 3D Printed Laminated Graphene Pressure Sensing Material Combines Extremely Low Detection Limits with Wide Detection Range

Abstract

Artificial intelligence robots predicted in sci-fi movies have attracted increasing attention in recent years, and much effort has been devoted to improving the sensing and manipulation performance of robots. The development of robotic skins capable of handling complex external pressure environments is highly desired for intelligent robots. However, this remains a major challenge due to the lack of pressure sensing materials that can combine extremely low detection limits and wide detection ranges. Inspired by the synergistic strategy of dual mechanoreceptors in human skin, here, the design and 3D printing of laminated graphene pressure sensing materials consisting of both ultrathin-and thick-walled cellular microstructures are demonstrated. Based on such laminated graphene, the piezoresistive pressure sensor achieves a low detection limit of 1 Pa, a wide detection range (1 Pa-400 kPa), and high sensitivities of 3.1 and 0.22 kPa −1 in the pressure regions of 1 Pa-13 kPa and 13−400 kPa, respectively, and the laminated graphenebased skin enables quantitative pressure/weight detection. This laminated graphene can be easily integrated into flexible pressure sensing arrays that enable mapping the spatial distribution of pressure, showing great potential for applications such as electronic skin, physiological signal monitoring, and human-machine interfaces.

EMI shielding and strain-sensitive tape based on ultraprecise 3D printed graphene oxide aerogel microlattices

“…Scanning electron microscopy (SEM) of GOAL (Fig. 3f-h) con rms that the printing accuracy (in terms of mono lament diameter) of the obtained GOAL is 70 µm which is signi cantly more precise than previously reported values (200-1000 µm) 12,14,15 . The grids are clearly visible, and the aerogel presents a porous foam internal structure.…”

“…5b). The RGOAL transferred onto the tape still maintains the piezoelectric properties of RGO-based aerogels 15,39 and thus as the tape is bent the resistance R changes accordingly. Figure 5e shows the variation of |ΔR/R 0 | under cyclic bending (10 cycles) at different bending degree de ned as |Δd|/L 0 (where L 0 represents the length of the tape when it is not bent).…”

“…The higher the accuracy, the smaller the scale of the printed part and the easier to regulate its microstructure. For functional devices based on graphene aerogels, higher printing accuracy translates to more functional units per unit volume, which is utterly critical to enhance their performance 14,15 .…”

Printed flexible mechanical sensors

“…Fabrication of flexible mechanical sensors by printing technologies have emerged as a versatile, economical, and enabling approach. For instance, various types of mechanical sensors (e.g., force, [33][34][35] pressure, [36][37][38][39][40] and strain [41][42][43][44][45][46] ) can be produced by leveraging many 2D/3D printing techniques including but not limited to screen printing, [47][48][49][50][51] inkjet printing, [52][53][54][55][56] direct ink writing (DIW), [57][58][59] digital light processing (DLP), [60][61][62] and fused filament fabrication (FFF). [63][64][65][66] The additive nature of printing technologies also largely reduces the fabrication cost and time; 67,68 in addition, fabrication by printing enabled the production of flexible mechanical sensors with excellent performance.…”

ISSI 2021: Direct-ink-writing printed strain rosette sensor array with optimized circuit layout

“…Compared with traditional 3D printing technologies such as light curing and laser melting, the DIW is exible and suitable for various functional pastes/inks composed of polymer and nano/micro conductive particles. Therefore, it is widely used to fabricate various novel sensors [10][11][12][13], and show signi cant advantages comparing with the screen/stencil printing [14][15][16][17] and spray coating [18,19]. For structural monitoring the strain sensor needs to be integrated with the substrate.…”