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Hybrid Printing for the Fabrication of Smart Sensors
Published on: January 31, 2019
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DLP 3D-Printed Conic-Pyramid Hydrogel Sensor for Wearable Devices and Handwritten Fingerprint Recognition
Dake Huang1, Jian Qi1,2, Shuo Gao1
1Tianjin High-end Intelligent CNC Machine Tool Engineering Research Center, Tianjin Key Laboratory of High Speed Cutting and Precision Processing, Tianjin University of Technology and Education, Tianjin 300222, China.
ACS Applied Materials & Interfaces
|August 5, 2025
Summary
This study developed a novel dual-ion conductive hydrogel sensor with multilevel conic-pyramid microstructures using 3D printing. This flexible sensor offers enhanced sensitivity, stability, and real-time monitoring for applications like identity authentication.
Area of Science:
- Materials Science
- Sensor Technology
- Biocompatible Materials
Background:
- Flexible hydrogel sensors are promising for wearable tech but face stability and sensitivity challenges.
- Traditional microstructure design relies on molds, limiting complex structure fabrication.
- Existing sensors struggle with performance degradation in diverse environments.
Purpose of the Study:
- To develop a stable, highly sensitive flexible hydrogel sensor with advanced microstructures.
- To overcome limitations of traditional hydrogel sensors through innovative design and fabrication.
- To demonstrate the sensor's potential in real-time monitoring and unique identification applications.
Main Methods:
- Fabrication of a dual-ion conductive hydrogel using acrylamide (AM)-poly(ethylene glycol) diacrylate (PEGDA) with a Mg2+/Na+ ion system.
- Incorporation of 30 wt% glycerol to enhance water retention (>90%) and ionic stability.
- Utilizing Digital Light Processing (DLP) 3D printing to create multilevel conic-pyramid microstructures for enhanced pressure sensing.
Main Results:
- The conic-pyramid structure achieved a sensitivity of 0.544 kPa-1 (0-0.8 kPa range), a 78% improvement over traditional pyramids.
- The sensor demonstrated rapid response (30 ms) and recovery (40 ms) times with high stability (>10,000 cycles, <4% attenuation).
- Enabled real-time monitoring of joint bending (55% variation) and wrist movements (64% variation), and "handwriting fingerprint" recognition (>2.5% signal difference).
Conclusions:
- The developed hydrogel sensor significantly enhances sensitivity and stability for flexible electronic applications.
- The conic-pyramid structure and dual-ion strategy provide a universal solution for sensor performance in complex environments.
- The "handwriting fingerprint" technology holds broad potential for identity authentication, medical monitoring, and anti-counterfeiting.
