Soft fibers with magnetoelasticity for wearable electronics

Area of Science:

• Materials Science
• Physics
• Engineering

Background:

• The magnetoelastic effect, a change in magnetic properties due to mechanical deformation, is typically observed in rigid metals and alloys.
• Stronger magnetomechanical coupling in soft materials remains an area of interest for novel energy harvesting applications.

Purpose of the Study:

• To investigate the presence and characteristics of the magnetoelastic effect in one-dimensional soft fibers.
• To develop a practical device for biomechanical-to-electrical energy conversion using this effect.

Main Methods:

• A wavy chain model incorporating magnetic dipole-dipole interactions and demagnetizing factors was used to explain the magnetoelastic effect in soft fibers.
• A textile magnetoelastic generator (MEG) was fabricated by weaving soft magnetoelastic fibers with conductive yarns.
• Performance metrics including short-circuit current density, internal impedance, and sensitivity to mechanical stimuli were measured.

Main Results:

• The magnetoelastic effect was successfully demonstrated in 1D soft fibers, exhibiting enhanced magnetomechanical coupling compared to traditional rigid materials.
• The developed textile MEG achieved a short-circuit current density of 0.63 mA cm⁻² and an internal impedance of 180 Ω.
• The MEG showed intrinsic waterproofness and successfully converted arterial pulse signals with a low detection limit of 0.05 kPa, even under conditions of heavy perspiration or submersion.

Conclusions:

• Soft fibers exhibit a significant magnetoelastic effect with potential for advanced applications.
• The textile magnetoelastic generator offers a novel and robust platform for biomechanical-to-electrical energy conversion.
• This technology demonstrates practical utility in wearable electronics and sensing, functioning reliably in challenging environments.