Highly Stretchable and Transparent Optical Adhesive Films Using Hierarchically Structured Rigid-Flexible...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Flexible electronic devices require advanced optical adhesive films with high elasticity and transparency.
• Existing materials often struggle to balance bonding strength with flexibility under strain.

Purpose of the Study:

• To develop a highly elastic and transparent optical adhesive film using novel dual-stiffness nanoparticles (DSNs).
• To investigate the impact of DSN structure and content on the film's mechanical and optical properties.

Main Methods:

• Synthesized hierarchical DSNs with a rigid SiO2 core and an elastic reactive coil shell.
• Fabricated optical adhesive films by incorporating DSNs into an acrylic polymer matrix.
• Characterized optical transmittance, adhesion strength, elastic modulus, stress relaxation, and strain recovery.

Main Results:

• The DSN-containing film achieved 92% optical transmittance and 19.9 N/25 mm adhesion strength.
• Increased DSN content improved elastic properties, including a 7.0 kPa elastic modulus and 73.6% strain recovery.
• Enhanced surface grafting density of elastic coils further improved stress relaxation (18.0%) and strain recovery (77.1%).

Conclusions:

• Novel dual-stiffness nanoparticles effectively enhance the elasticity and transparency of optical adhesive films.
• These films demonstrate superior performance under strain, making them suitable for demanding flexible electronic applications.
• The tailored nanoparticle design offers a promising pathway for advanced materials in flexible electronics.