Electrospining Machine: Flexible Humidity Sensor with High Sensitivity and Durability for Respiratory Monitoring Using Near-Field Electrohydrodynamic Direct-Writing Method

Background

On June 1, 2023, Taiyao Pan's team published a new research paper in ACS Applied Materials & Interfaces (impact factor: 8.3), "Flexible Humidity Sensor with High Sensitivity and Durability for Respiratory Monitoring Using Near-Field Electrohydrodynamic Direct-Writing Method". Important progress has been made in near-field electrohydrodynamic direct writing and flexible humidity sensors.

Method

In this work, near-field electrohydrodynamic direct writing is proposed to fabricate a respiratory monitoring humidity sensor with high sensitivity and durability. Due to the effect of the applied electric field, a dense carbon Electrospun Nanofbers/cellulose Electrospun Nanofbers network is formed during the printing process, which enhances the sensitivity of the sensor. The prepared sensor has good sensitivity under different simulated conditions such as nasal breathing, mouth breathing, coughing, yawning, breath holding and talking, showing the potential of the sensor in real-time monitoring of human respiratory humidity.

Research innovation

Novel manufacturing method:

Relying on electrospinning machine using near-field electrofluidic direct writing (NFEDW) method is proposed for the fabrication of flexible humidity sensors with high sensitivity and durability, which provides a new technological path for the production of humidity sensors.

figure 1. NFEDW equipment and production diagram

Has significant humidity sensitivity:

Evaluate its humidity sensitivity by analyzing resistance changes under different RH conditions. The sensor has a maximum response of 61.5% at 95% RH.

figure2. Moisture sensitivity test of NFEDWHS and control group

Extremely high flexibility: 

The corresponding NFEDWHS can withstand extreme bending (maximum curvature of 4.7 cm−1) and folding (up to 50 times) without significant loss of sensitivity.

Figure 3. Dynamic response and recovery curves of NFEDWHS under different bending states

Excellent performance under various breathing conditions: 

The sensor exhibits good sensitivity under different simulated conditions (such as nasal breathing, mouth breathing, coughing, yawning, breath holding, and talking), demonstrating its potential in real-time monitoring of human breath humidity.

Figure 4. Sensor humidity sensitivity under different simulated conditions

Simple sensor structure: 

The sensor consists of a humidity sensitive layer and a flexible PET substrate. It is simple in design, easy to produce, and easy to promote in practical applications.

This study demonstrates the great potential of near-field electrohydrodynamics in the field of humidity sensors, especially in the manufacture of respiratory monitoring with high sensitivity and durability. The research results can also be used for human respiratory and health monitoring, showing a wide range of application potential in clinical and health monitoring fields.

link：https://pubs.acs.org/doi/full/10.1021/acsami.3c04283