Electrospun CuS/PVP Nanowires and Superior Near-Infrared Filtration Efficiency for Thermal Shielding Applications.

Selective filtration of near-infrared (NIR) regions is of primary importance to energy saving via thermal shielding. However, uniform coating of highly effective nanomaterials on flexible substrates remains very challenging. Here, we introduce new material processing and fabrication methodologies that manufacture electrospun copper sulfide/polyvinylpyrrolidone (CuS/PVP) nanowires for enhanced thermal shielding efficiency. Electrospinning offers well-dispersed CuS nanoparticles in a thermal shielding film, which is not achievable in typical solution coating processes. Directly deposited CuS/PVP nanowires on a flexible polymer membrane are enabled by a fluorination treatment that decreases the interfacial electrostatic repulsion. Monitoring of in situ temperature change of a box-shielded, CuS/PVP nanowire film demonstrates excellent NIR shielding efficiency (87.15%). Direct integration of the film with a model car and exposure to direct sunlight demonstrates about twice-higher shielding efficiency than commercial tungsten oxide films. Overall, the comprehensive study of nanomaterial preparation, surface treatment, and integration techniques allows the fabrication of highly flexible and reliable thermal shielding films.