Polymer-Thread-Based Fully Textile Capacitive Sensor Embroidered on a Protective Face Mask for Humidity Detection.

Area of Science:

• Materials Science
• Textile Engineering
• Sensor Technology

Background:

• The COVID-19 pandemic necessitated widespread face mask usage, highlighting the need for enhanced functionality in personal protective equipment.
• Integrating smart functionalities into everyday items like face masks presents an opportunity for advancements in wearable technology.

Purpose of the Study:

• To develop and evaluate an embroidered humidity sensor integrated into single-use face masks.
• To explore the potential of polymer-based textile materials for creating novel sensing devices.

Main Methods:

• An embroidered humidity sensor was designed using interdigitated electrodes made of polyamide-based conductive threads and polyester threads as the dielectric sensing layer.
• The sensor's performance was assessed by measuring capacitance changes under varying relative humidity (RH) levels across a frequency range of 1 Hz to 100 kHz.
• Limit of detection (LOD) and sensor stability/repeatability were evaluated.

Main Results:

• The embroidered sensor, acting as a capacitor, demonstrated measurable capacitance changes corresponding to different RH levels due to moisture adsorption by the polyester threads.
• Calculated LOD values ranged from 11.46% RH to 38.65% RH across tested frequencies.
• The sensors exhibited good repeatability and stability over an 80-minute period.

Conclusions:

• Direct embroidery of conductive and moisture-sensitive threads onto face masks enables the creation of functional e-textile sensing devices.
• This approach offers a novel method for integrating stretchable sensing capabilities into common textile products.
• The developed humidity sensor integrated into face masks shows promise for various e-textile applications.