Large-scale ordering of nanoparticles using viscoelastic shear processing

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Assembling nanoparticles into ordered superstructures for photonic materials is difficult.
• Existing methods lack scalability and efficiency for creating complex nanostructures.

Purpose of the Study:

• To develop a scalable method for assembling polymer nanoparticles into photonic crystals.
• To demonstrate the creation of tunable structural color in polymer opals using a novel technique.

Main Methods:

• Utilized a bending-induced oscillatory shear technique in a roll-to-roll process.
• Employed sub-micron spherical polymer nanoparticles and high oscillatory strain amplitudes (300%).
• Applied bidirectional shearing to improve the ordered structure of nanoparticle layers.

Main Results:

• Successfully assembled flexible films of stacked polymer nanoparticles into elastomeric photonic crystals (polymer opals).
• Achieved highly tunable structural color with strong intensity due to the ordered nanoparticle arrangement.
• Demonstrated rapid crystallization across the bulk material within five oscillations.

Conclusions:

• The bending-induced oscillatory shear technique enables direct, scalable fabrication of photonic materials.
• The developed method provides a generic tool for ordering nanoparticles in viscoelastic media.
• This approach facilitates the creation of manufacturable photonic materials with tunable optical properties.