Highly Robust and Multimodal PVA/Aramid Nanofiber/MXene Organogel Sensors for Advanced Human-Machine Interfaces

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Electronics

Background:

• Flexible and wearable electronics demand soft sensing materials with mechanical compliance, signal stability, and durability for human-machine interfaces (HMIs).
• Existing single-filler systems face limitations in achieving multifunctional soft platforms.
• There is a need for integrated materials that can support multiple sensing functionalities for advanced HMIs.

Purpose of the Study:

• To develop a multifunctional soft platform for flexible and wearable electronics.
• To create a poly(vinyl alcohol) (PVA)/aramid nanofiber (ANF)/MXene organogel (PAM) composite with enhanced mechanical and electrical properties.
• To demonstrate the configurability of the PAM platform into multiple sensing modalities for advanced HMIs.

Main Methods:

• Fabrication of a poly(vinyl alcohol) (PVA) physically crosslinked network integrated with aramid nanofiber (ANF) for mechanical reinforcement and MXene for electrical functionality.
• Optimization of the PAM composite to achieve superior mechanical properties, including high fracture stress, strain, and toughness.
• Configuring the PAM platform into three distinct sensing modalities: resistive strain sensor, capacitive pressure sensor, and triboelectric nanogenerator (TENG).

Main Results:

• The optimized PAM composite exhibited outstanding mechanical properties: fracture stress of 2931 kPa, fracture strain of 676%, and fracture toughness of 9.04 MJ m^-3.
• The resistive strain sensor achieved a gauge factor of 3.1 and reliably recognized human joint movements.
• The capacitive pressure sensor showed high sensitivity (0.298 kPa^-1) and rapid response times, enabling wireless control of a smart car.
• The PAM-based TENG generated significant electrical outputs (V_oc = 123 V, I_sc = 0.52 μA, Q_sc = 58 nC) and functioned as a self-powered handwriting pad with 97.6% machine-learning recognition accuracy.

Conclusions:

• The developed PAM organogel serves as a versatile, single-material platform for multiple sensing applications.
• The PAM composite demonstrates excellent mechanical robustness and tunable electrical functionalities.
• This work highlights the potential of PAM organogel for creating advanced, self-powered human-machine interfaces.