Micro-/nano-voids guided two-stage film cracking on bioinspired assemblies for high-performance electronics

Area of Science:

• Materials Science
• Nanotechnology
• Biomimetics

Background:

• Current metal film electronics exhibit limited stretchability (~30%) due to uncontrolled cracking, hindering practical applications.
• The need for highly stretchable and sensitive electronic materials is critical for advanced sensor and wearable technology.

Purpose of the Study:

• To design and demonstrate a novel electronic surface with enhanced stretchability and sensitivity.
• To investigate a biomimetic approach inspired by cochlear stereocilia bundles for crack retardation.

Main Methods:

• Hierarchical assembly of interfacial nanowires to create a structured surface.
• Utilizing micro- and nano-voids to induce a two-stage cracking process.
• In-situ observation to analyze crack propagation mechanisms under varying strains.

Main Results:

• Achieved a stretchability of 130%, a significant improvement over flat counterparts (30%).
• Maintained high sensitivity, detecting strains as low as 0.005%.
• Demonstrated that micro-voids guide initial crack growth, while nano-voids initiate new cracks at larger strains.

Conclusions:

• The biomimetic hierarchical nanowire structure effectively retards crack propagation, enhancing electronic device stretchability.
• This design offers a promising pathway for developing robust, highly sensitive stretchable electronics for diverse applications.
• The understanding of the two-stage cracking mechanism provides insights for future material design.