Assessing radiative cooling potential of polymeric films: A quality factor for energy-efficient materials

We investigated the infrared radiation (IR) absorption coefficients of several polymer types to propose a novel approach through the development of radiative-cooling polymeric films and composites. We studied polymeric films and their infrared characterization for selective IR radiation absorption. Specifically, we prepared and analyzed films of Styrene-Isoprene-Styrene (SIS), Styrene-Butadiene-Styrene (SBS), and Styrene-Ethylene-Butadiene-Styrene (SEBS) copolymers for radiative cooling applications. The linear optical properties of the films in the mid-infrared range were characterized using Fourier-transform infrared (FT-IR) spectrophotometry. To evaluate the cooling performance, we introduced a quality factor that accounts for emissivity within the two key infrared transmission windows of Earth's atmosphere. Based on the experimental results, we calculated the quality factor to compare the radiative cooling efficiency of the different investigated polymers. • Polymeric materials can be efficiently prepared as films or coatings for selective mid-infrared radiation absorption. • Infrared spectroscopy is a useful tool to highlight emissivity values within the transparency windows of Earth's atmosphere. • Radiative cooling quality factor can be defined and calculated to compare cooling performance across polymer types. • Polymers that maximize cooling efficiency are strategic tools in sustainable building-design and climate control technologies.