High-performance polyacrylic acid/ carboxylated cellulose nanofibers hydrogel sensor for human-machine interaction

Area of Science:

• Materials Science
• Polymer Chemistry
• Sensor Technology

Background:

• Ion-conductive hydrogels are ideal for flexible sensors due to efficient ion migration and fast response.
• Optimizing mechanical, electrical, and sensing properties simultaneously in these hydrogels remains a significant challenge.
• Existing materials often struggle with performance across diverse environmental conditions and mechanical stresses.

Purpose of the Study:

• To synthesize a novel dual-network ion-conductive hydrogel (PCN) with enhanced and synergistic properties.
• To investigate the structure-property relationships, focusing on mechanical robustness, electrical conductivity, and sensing capabilities.
• To evaluate the hydrogel's potential for advanced applications in flexible sensing and human-computer interaction.

Main Methods:

• A dual-network ion-conductive hydrogel (PCN) was synthesized using in-situ thermal radical polymerization.
• The hydrogel structure was reinforced by multiple cross-linking mechanisms: covalent bonds, ionic bonds, and hydrogen bonds.
• Mechanical properties (tensile strain, tensile strength) and sensing performance (gauge factor across strain and temperature) were systematically characterized.

Main Results:

• The optimal hydrogel (PCN-30) demonstrated superior mechanical properties (938% tensile strain, 0.23 MPa tensile strength) over wide temperature ranges.
• PCN-30 exhibited excellent sensing linearity with strain (10-300%) and temperature variations (15-45°C and -35-15°C), with average gauge factors of 1.71, 2.46, and 1.63, respectively.
• The sensor enabled precise motion and vital sign detection, alongside effective information transmission.

Conclusions:

• The developed dual-network ion-conductive hydrogel (PCN) successfully integrates robust mechanical properties with sensitive electrical responses.
• PCN-30 exhibits remarkable environmental adaptability and wide-range sensitive response, addressing previous limitations in hydrogel-based sensors.
• This material significantly advances the practical application of flexible sensors in human-computer interaction.