Highly sensitive pressure sensor based on structurally modified tissue paper for human physiological activity monitoring

Abstract

Pressure sensor has become an important part of physiological condition monitoring system because it can respond to small pressure in human activities. Tissue paper has been studied as a carrier of sensitive unit layer for pressure sensors in recent years due to its internal pore structure and wrinkle morphology of surface. In this work, the pore structure of the tissue paper is improved by the principle of hydration and destruction of hydrogen bonds. Based on flexible substrate of NaOH modified tissue paper (NMTP) with enhanced pore structure, combined with dip-coating composite conductive filler, the pressure sensor is fabricated by sandwiching the sensitive unit between the interdigital electrode and the microdome elastomer through layer-by-layer assembly method. Thanks to the excellent interfacial resistance effect of porous NMTP under pressure, the sensitivity of NMTP-based pressure sensor is as high as 37.5 kPa −1 in a pressure range of 0-2 kPa. Finally, the follow-up studies on pressure sensors have been proven to be applicable to a variety of physiological activity such as pulse detection, respiration detection and voice recognition. The NMTP-based sensitive unit provides alternative strategy to improve performance of pressure sensors and extends potential applications in monitoring human physiological activities.

Transduction Mechanisms, Micro-Structuring Techniques, and Applications of Electronic Skin Pressure Sensors: A Review of Recent Advances

“…Despite their low-cost, all these techniques also have a limited level of design tailoring. Fabrication of 3D printed molds [ 78 , 241 , 242 , 243 , 244 ] (majorly to micro-structure PDMS or PDMS composites) or direct printing of materials with a 3D printer [ 245 , 246 ], which is a low-cost approach to achieve a micro-structuring, nonetheless typically only allows the achievement of structures with a size in the order of few mm due to printer and filament constraints. Production of molds through laser engraving technique .…”

“… Laser cutting and Photolit. 374.5 (0–0.3) 3.86 (0.3–20) 0.63 (20–80) 2.5 Pa/ 80 kPa -/- 10 4 (L) 1 V/- (♡ ) PR P. Liu [ 244 ] 2020 NaOH modified tissue paper with silicon rubber, carbon black, and graphene nanoplates as active layer, silicon rubber micro-domes, and interdigitated elec. of Au on PI.…”

Large-Scale, Cuttable, Full Tissue-Based Capacitive Pressure Sensor for the Detection of Human Physiological Signals and Pressure Distribution

“…On the one hand, the conductive materials, including metal nanoparticles/nanowires, − carbon-based materials, − MXene (Ti 3 C 2 T x ), − indium tin oxide (ITO), , and conducting polymers, , have been widely used in the flexible capacitive stress sensors. On the other hand, the supporting layer materials of the electrode, such as poly­(dimethylsiloxane) (PDMS), , polyimide (PI), Ecoflex, poly­(methyl methacrylate) (PMMA), fibers, , and tissues, are required to be highly flexible, superbly stable, and biocompatible. The fabrication of macromolecular polymers generally needs complicated curing processes and relatively high material costs.…”

Rational Design of a Novel Highly Folding-tolerable Edgewo-rthia Chrysantha Lindi-derived Substrate for Versatile Flexible Pressure Sensors

“…Due to its advantages of high e ciency, good uniformity and strong adhesion, the obtained cellulose-based composite showed good potential in detecting human activities. In addition, highly porous tissue papers were employed as an appealing substrate to fabricate exible electronics by Huang et al (Huang et al 2020) The tissue paper was pretreated with NaOH to destroy the hydrogen bonds between cellulose molecules, thereby promoting the expansion of cellulose bers and improving the sensitivity of this composite-based pressure sensors. However, the mechanical and sensing properties of the sensors listed above still cannot meet the needs of next-generation FPSs.…”