Carbonized Cotton Fabric-Based Flexible Capacitive Pressure Sensor Using a Porous Dielectric Layer with Tilted Air Gaps

Abstract

Flexible and wearable pressure sensors have attracted significant attention owing to their roles in healthcare monitoring and human–machine interfaces. In this study, we introduce a wide-range, highly sensitive, stable, reversible, and biocompatible pressure sensor based on a porous Ecoflex with tilted air-gap-structured and carbonized cotton fabric (CCF) electrodes. The knitted structure of electrodes demonstrated the effectiveness of the proposed sensor in enhancing the pressure-sensing performance in comparison to a woven structure due to the inherent properties of naturally generated space. In addition, the presence of tilted air gaps in the porous elastomer provided high deformability, thereby significantly improving the sensor sensitivity compared to other dielectric structures that have no or vertical air gaps. The combination of knitted CCF electrodes and the porous dielectric with tilted air gaps achieved a sensitivity of 24.5 × 10−3 kPa−1 at 100 kPa, along with a wide detection range (1 MPa). It is also noteworthy that this novel method is low-cost, facile, scalable, and ecofriendly. Finally, the proposed sensor integrated into a smart glove detected human motions of grasping water cups, thus demonstrating its potential applications in wearable electronics.

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

“…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. , …”

“…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. 64,65 3.3. Sensing Performances and Mechanism of the Flexible Pressure Sensor.…”

3D Printing of Carbon Nanotube (CNT)/Thermoplastic Polyurethane (TPU) Functional Composites and Preparation of Highly Sensitive, Wide‐range Detectable, and Flexible Capacitive Sensor Dielectric Layers via Fused Deposition Modeling (FDM)

“…Under the compression condition, the pores in the dielectric layer gradually close, the volume fraction of air decreases and the volume fraction of the CNT/TPU dielectric layer increases. [ 49 ] This increases the effective dielectric constant of the porous CNT/TPU dielectric layer. When the air gap is introduced into the dielectric layer, the sensitivity of the pressure sensor is improved due to its enhanced deformability.…”

A Review on Knitted Flexible Strain Sensors for Human Activity Monitoring

“…Carbonization is to place the fabric in an oxygen-deprived or oxygen-poor state, decompose the macromolecules in the fiber, and part of the carbon atoms are reorganized and recrystallized into a partially graphitized carbon structure with certain electrical conductivity. [105,106] Its technical advantage is low cost, wider adaptability to the raw material, and easy large-scale production. [107] Knitted strain sensors prepared by carbonization combining the high elasticity of knitted materials with the electrical conductivity of carbon-based substances.…”