Stretchable Conductive Composites from Cu-Ag Nanowire Felt

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Wearable electronics require materials that maintain high electrical conductivity even when subjected to mechanical strain.
• Existing conductive composites often compromise conductivity for stretchability, limiting their application.

Purpose of the Study:

• To develop a novel conductive and stretchable composite material for advanced wearable electronic applications.
• To investigate the relationship between matrix stiffness, mechanical properties, conductivity retention, and deformation mechanisms in a nanowire-elastomer composite.

Main Methods:

• Fabrication of a composite using a Cu-Ag core-shell nanowire felt infiltrated with a silicone elastomer of varying stiffness.
• Characterization of the composite's electrical conductivity, mechanical properties (Young's modulus), and deformation behavior under strain.
• Analysis of the impact of matrix Young's modulus on conductivity retention and the underlying deformation mechanisms, including void formation.

Main Results:

• The developed composite demonstrated superior retention of conductivity under strain compared to other composites with conductivity > 1000 S cm^-1.
• Conductivity retention decreased with increasing matrix stiffness (Young's modulus), attributed to void formation from nanowire-elastomer debonding.
• The composite was successfully patterned into serpentine circuits exhibiting 300% stretchability.

Conclusions:

• The Cu-Ag core-shell nanowire composite offers exceptional conductivity retention under strain, crucial for robust wearable electronics.
• Optimizing silicone matrix stiffness is key to balancing mechanical integrity and conductivity preservation, with lower stiffness favoring better conductivity retention.
• The findings provide a pathway for designing high-performance, stretchable conductive materials for next-generation flexible and wearable devices.