Thermoresponsive polymer composites for wavelength-independent light scattering control

Controlling light scattering in optical materials is critical for next-generation energy-efficient devices, smart displays, and adaptive solar management. This study introduces a class of thermoresponsive polymer composites designed to achieve wavelength-independent light scattering through temperature-driven refractive index modulation. The composites consist of a poly(ethylene-co-vinyl acetate) (PEVA) matrix embedded with poly(methyl methacrylate-co-styrene) (PMMA-co-PS) microparticles serving as scattering agents.

Using a melt-blending and hot-pressing process, the effects of particle size (3 μm and 10 μm), loading concentration (1–20 wt%), and binary particle composition were systematically optimized. The resulting temperature-sensitive light scattering modifiers (TS-LSMs) exhibited a high total transmittance of approximately 92 % and a dynamically tunable haze range from 35 % to 90 % over 0–70 °C. This tunability originates from thermally induced refractive index mismatch between matrix and filler, as well as the reversible formation of micropores within the polymer phase.

Significantly, dual-particle systems achieved wavelength-independent scattering, overcoming chromatic distortion common in conventional diffusive films. Multilayer configurations further enhanced mechanical integrity and scalability without compromising optical performance.

This work establishes a materials-design framework for developing temperature-adaptive optical films capable of maintaining uniform scattering behavior across the visible spectrum. Such tunable composites offer strong potential for smart windows, energy-saving display panels, and adaptive solar-control coatings, contributing to both energy efficiency and sustainable photonic technologies.

Dr. Jun-Young Lee is a senior researcher at the Korea Institute of Industrial Technology (KITECH), specializing in the study of functional microstructured materials developed through polymer synthesis and processing. His research outcomes have been widely applied in various fields, including packaging and films for electronics, agriculture, and food industries.