Hazy transparent cellulose nanocrystal-based films with tunable structural colors

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Cellulose nanocrystals (CNCs) are versatile biosourced nanomaterials.
• Chiral photonic films from CNCs are known for optical properties.
• Surface roughness engineering remains underexplored for modifying CNC film optics.

Purpose of the Study:

• To engineer surface roughness in CNC-based chiral photonic films.
• To optimize optical properties like haze and transmittance.
• To explore applications in optical diffusion and tunable structural colors.

Main Methods:

• Vacuum filtration-assisted self-assembly of CNCs.
• Imprinting surface texture from filtration membranes.
• Characterization of optical haze, transmittance, and structural color.

Main Results:

• Achieved densely packed CNC films with high optical transparency.
• Demonstrated CNC films with engineered surface roughness.
• Optimized optical haze (99%) and transmittance (62%) simultaneously.
• Exhibited broadband transmission and tunable structural colors across the visible spectrum.

Conclusions:

• Surface roughness engineering is a viable method to control optical properties of CNC films.
• Developed a simple technique for creating hazy transparent CNC films.
• Demonstrated potential for CNC films as optical diffusers with tunable color temperature.