Polymer Multilayer Heterostructure Greenhouse Cladding Material With Wavelength Selection and Nighttime Thermal Insulation

Abstract The simultaneous realization of spectral selectivity and thermal management positions this innovation as a promising solution for modern greenhouse agriculture. This paper presents a polymer multilayer heterostructure greenhouse cladding material utilizing quarter-wave stacks (QWS) composed of polyethylene terephthalate (PET) and ethylene vinyl acetate copolymer (EVA). The structure comprises multiple EVA/PET QWS, with their geometric parameters optimized via a genetic algorithm (GA). Among them, the number of three quarter-wave stacks demonstrated excellent optical performance, the structure exhibits 97.95% average reflectivity in the green spectrum (520–580 nm), 88.16% average transmittance across visible wavelengths (400–520 nm and 580–780 nm), and 86.69% transmittance in near-infrared regions (780–2500 nm). Additionally, the film demonstrates 84.32% infrared blocking efficiency within the atmospheric window (7–14 μm). Notably, the designed structure demonstrates exceptional angular stability, with its reflectivity, transmittance, and infrared blocking rate showing minimal sensitivity to changes in incident light angle from 0 to 60°. Through leveraging the intrinsic absorption characteristics of polymeric materials and structural optimization of stacked multilayer structures, this structure exhibits infrared blocking capability and spectral modulation of sunlight wavelengths.