Upcycling Chips-Bags for Passive Daytime Cooling

Plastic pollution has caused numerous environmental issues in recent decades. As one of the most commonly used packaging materials, aluminum-plastic laminates (APL) are particularly challenging for recycling purposes due to their sophisticated materials components. This work reveals a new strategy to upcycle such post-consumer APL packaging waste, e.g., chips-bags, for passive daytime cooling applications. This opens an attractive route to reuse APLs while at the same time reducing global energy consumption and carbon emissions. The mirror-like appearance of the APLs possesses a strong solar reflection, up to 86%. By coating, this reflective layer of the APL waste with a high emissive polydimethylsiloxane layer, a simple but effective passive daytime cooling foil is constructed, which shows promising passive cooling performance theoretically and practically. More importantly, the passive cooling foil based on APL waste is flexible and can be applied to any target object, protecting it from harsh sunlight. The low-cost APL waste-based passive cooling foil proposed in this work will significantly contribute to both energy and environmental issues that humans face today.