Rapid Prototyping Flexible Capacitive Pressure Sensors Based on Porous Electrodes

Abstract

Flexible pressure sensors are widely applied in tactile perception, fingerprint recognition, medical monitoring, human–machine interfaces, and the Internet of Things. Among them, flexible capacitive pressure sensors have the advantages of low energy consumption, slight signal drift, and high response repeatability. However, current research on flexible capacitive pressure sensors focuses on optimizing the dielectric layer for improved sensitivity and pressure response range. Moreover, complicated and time-consuming fabrication methods are commonly applied to generate microstructure dielectric layers. Here, we propose a rapid and straightforward fabrication approach to prototyping flexible capacitive pressure sensors based on porous electrodes. Laser-induced graphene (LIG) is produced on both sides of the polyimide paper, resulting in paired compressible electrodes with 3D porous structures. When the elastic LIG electrodes are compressed, the effective electrode area, the relative distance between electrodes, and the dielectric property vary accordingly, thereby generating a sensitive pressure sensor in a relatively large working range (0–9.6 kPa). The sensitivity of the sensor is up to 7.71%/kPa−1, and it can detect pressure as small as 10 Pa. The simple and robust structure allows the sensor to produce quick and repeatable responses. Our pressure sensor exhibits broad potential in practical applications in health monitoring, given its outstanding comprehensive performance combined with its simple and quick fabrication method.

Bamboo-Inspired, Environmental Friendly PDMS/Plant Fiber Composites-Based Capacitive Flexible Pressure Sensors by Origami for Human–Machine Interaction

“…For example, carbon nanotubes and metal nanoparticles can be added to the sensor as conductive fillers. , Second, optimization of sensor structure: by optimizing the structural design of the sensor, the electric field distribution and capacitance change characteristics of the sensor can be improved, thus increasing the sensitivity. For example, the fork-finger electrode structure and micronano structure can be used. , …”

“…For example, the fork-finger electrode structure and micronano structure can be used. 62,63 Besides, regulation of the porosity of the sensing layer may be a strategy worth considering. The elastic deformation of the sensing layer can be improved by methods such as the sacrificial template method and increasing the internal porosity of the fabric, thus enhancing the sensing performance.…”

Flexible and Stretchable Pressure Sensors: From Basic Principles to State-of-the-Art Applications

“…Flexible and stretchable pressure sensors employing capacitive sensing typically consist of two conductive layers separated by a dielectric layer. The conductive layers can be made of metals [ 24 ] or conductive polymers [ 25 ] while the dielectric layer is often an elastomeric material with a high dielectric constant [ 26 ]. When pressure is applied to the sensor, the deformation of the elastomeric layer leads to a change in the separation distance between the conductive layers, thereby altering the capacitance.…”

A Pressure and Proximity Sensor Based on Laser-Induced Graphene

“…Currently, flexible pressure sensors are categorized into resistance type, capacitance type, piezoelectric type, and triboelectric type based on their working principle [ 6 , 7 , 8 ]. Among these types, capacitive pressure sensors offer advantages such as simple structure, insensitivity to temperature and humidity, low power consumption, and wide applicability in human-computer interaction, medical health, robot haptics, and other fields [ 9 , 10 , 11 ]. However, these advantages also necessitate more stringent substrate material requirements [ 12 , 13 ].…”