Inkjet Printed Textile Force Sensitive Resistors for Wearable and Healthcare Devices

Area of Science:

• Materials Science
• Textile Engineering
• Wearable Technology

Background:

• Force sensitive resistors (FSRs) are crucial for monitoring physiological signals and motion in wearable devices.
• Existing FSRs lack suitability for seamless integration into wearable platforms.
• A need exists for robust, integrable pressure sensors in textile-based healthcare applications.

Purpose of the Study:

• To develop novel textile force sensitive resistors (TFSRs) for enhanced integration into wearable healthcare devices.
• To demonstrate a facile fabrication method for TFSRs using inkjet printing and heat pressing.
• To characterize the tunable pressure sensitivity and switching behavior of the developed TFSRs.

Main Methods:

• Inkjet printing of metal-organic decomposition silver inks onto textile substrates.
• Utilizing a thermoplastic polyurethane (TPU) membrane with controlled voids as a piezoresistive structure.
• Heat pressing for facile integration of electrodes and membrane into textiles.
• Characterization of pressure activation range (4.9 kPa to 7.1 MPa) by adjusting TPU layer number and hole diameter.

Main Results:

• Successfully fabricated textile FSRs (TFSRs) with integrated piezoresistive structures.
• Demonstrated tunable pressure sensitivity by modifying the TPU spacer design.
• Achieved stable signal acquisition for finger movement detection using TFSRs with a readout circuit and mobile app.
• Validated TFSRs as functional textile switches with tactile feedback capabilities.

Conclusions:

• The developed TFSRs offer a promising solution for pressure sensing in wearable healthcare.
• The inkjet printing and heat pressing method enables facile integration into textiles.
• TFSRs exhibit controllable switching behavior and stable signal output, suitable for various applications.