Nanocellulose-Enhanced, Easily Processable Cellulose-Based Flexible Pressure Sensor for Wearable Epidermal Sensing

Area of Science:

• Materials Science
• Nanotechnology
• Biomass Engineering

Background:

• Flexible pressure sensors (FPSs) are crucial for wearable electronics, human-machine interaction, and environmental monitoring.
• Biomass-derived materials offer sustainable and versatile platforms for advanced sensor development.
• Cellulose-based materials, particularly cellulose nanofibers (CNFs), show promise due to their unique properties.

Purpose of the Study:

• To develop a high-performance flexible pressure sensor (FPS) using a novel composite paper.
• To investigate the advantages of cellulose nanofibers (CNFs) over other cellulose forms (bacterial cellulose and cellulose nanocrystals) in sensor applications.
• To demonstrate the potential of the developed sensor for various human-interactive applications.

Main Methods:

• A facile papermaking strategy was employed to assemble flexible silver nanowire-dual-cellulose paper (SNdCP).
• The composite paper incorporated common cellulose fibers, cellulose nanofibers (CNFs), and silver nanowires (AgNWs).
• Mechanical and electrical properties were characterized, and sensor performance was evaluated for responsiveness to various stimuli.

Main Results:

• The SNdCP composite paper exhibited enhanced mechanical properties (tensile stress of 164.65 MPa) and electrical conductivity (11600 S·m^-1) compared to BC and CNCs.
• The fabricated FPS demonstrated high sensitivity (0.050 kPa^-1), rapid response/recovery times (158/95 ms), and excellent stability (>1000 bending cycles).
• The sensor successfully detected finger motions, recognized voice commands, and monitored human pulses, maintaining performance in array configurations.

Conclusions:

• Cellulose nanofibers (CNFs) provide superior reinforcement and conductivity for biomass-based flexible pressure sensors.
• The developed SNdCP material offers a facile and versatile platform for fabricating high-performance, human-interactive FPSs.
• This approach provides valuable insights for creating advanced cellulose-based sensors for diverse technological applications.