Near-Infrared Reflective Polymer Films Based on UV-327-Doped Zinc Oxide Nanoparticles

Area of Science:

• Materials Science
• Optics
• Polymer Science

Background:

• Cholesteric liquid crystals (CLCs) exhibit selective reflection of light.
• Achieving broadband reflection in CLCs is crucial for applications like smart windows and laser shielding.
• Controlling pitch gradient in CLCs is key to broadening reflection bandwidth.

Purpose of the Study:

• To develop cholesteric liquid crystal (CLC) films with broadband reflective properties.
• To investigate the effect of UV-absorbing dyes and zinc oxide nanoparticles (ZnO NPs) on CLC film reflection bandwidth.
• To optimize the preparation technology for broadband reflective CLC films.

Main Methods:

• Admixing organic dye UV-327 and inorganic zinc oxide nanoparticles (ZnO NPs) into CLC films.
• Utilizing a pitch distribution gradient from large to small along the film thickness.
• Employing UV-absorbing dyes to create a UV intensity gradient, influencing monomer polymerization and chiral molecule concentration.

Main Results:

• Achieved a broadened reflective bandwidth of up to 881 nm.
• The CLC films exhibit good coverage in the near-infrared wavelength band.
• The addition of UV-327 improved dispersion and compatibility of ZnO NPs within the CLC system.

Conclusions:

• The developed CLC films demonstrate significant broadband reflective properties.
• The method offers a promising approach for preparing advanced CLC films for optical applications.
• Potential applications include smart windows, laser shielding in medical and military fields.