Multilayer cellulose hybrid films with tunable UV selectivity and mechanical performance

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Renewable polymer films require low thickness, mechanical robustness, and selective UV shielding for lightweight applications.
• Conventional cellulose films face challenges balancing mechanical integrity and optical selectivity with UV additives.

Purpose of the Study:

• To develop an interface-engineered multilayer design for regenerated cellulose films.
• To overcome the trade-off between mechanical performance and optical selectivity in cellulose-based UV-shielding films.

Main Methods:

• Modular stacking of regenerated cellulose (RC) layers to improve interlayer densification and stress transfer.
• Incorporation of sepiolite as a nano-reinforcement to enhance mechanical properties.
• Utilizing SiO₂ for tunable UV-C attenuation and sharp absorption edges.

Main Results:

• Multilayer stacking improved tensile compliance, reaching ~7.5% elongation at break.
• Sepiolite reinforcement yielded tensile strengths up to ~9.4 MPa while maintaining cellulose crystallinity.
• SiO₂ enabled tunable UV-C attenuation with adjustable absorption edges and low transmittance below 280 nm.

Conclusions:

• The multilayer design allows independent assignment of mechanical and optical functions to different layers.
• This approach enables programmable UV-edge tuning without altering bulk composition.
• The developed films offer a sustainable and scalable solution for advanced protective materials.