Strain-induced optical degradation on thermal performance of radiative cooling-coated PVC membrane

Radiative cooling-coated polyvinyl chloride (PVC) membranes offer an effective solution to reduce cooling energy demand in membrane-based buildings. However, PVC membranes as load-bearing components are subjected to significant tensile deformation, which may alter the microstructure of the coating and degrade its spectral selectivity and cooling capacity. In this study, a radiative cooling coating was developed and applied to PVC membranes, and its optical stability and cooling performances under varying uniaxial strains were systematically investigated through macro-scale measurements and micro-structural analysis. It is obtained that uniformly dispersed BaSO₄ microparticles enhance Mie scattering, enabling a solar reflectance of 92.4% across 0.3–2.5 μm. Abundant functional groups contribute to a high mid-infrared emissivity of 93.1% in the 8–13 μm atmospheric window. With increasing strain, surface roughening and crack formation disrupt scattering paths, resulting in a reflectance reduction to 87.5%, while the chemical structure remains stable and emissivity only slightly decreases to 92.0%. Outdoor tests confirm that unstrained membrane achieves a peak temperature reduction of 12.9 °C due to high reflectance and high emissivity. Tensile strain weakens Mie scattering and reduces cooling efficiency, but the coated membrane still achieves a 10.1 °C temperature drop until 20% strain. This study reveals the strain-dependent optical and thermal mechanisms of radiative cooling coatings in their application to membrane materials, and provides technical and theoretical support for the performance evaluation and practical utilization of radiative cooling-coated membrane structures. © 2026 Elsevier B.V.