Superhydrophobic and mechanical properties enhanced the electrospinning film with a multiscale micro-nano structure for high-efficiency radiation cooling

Abstract

To date, although radiation cooling technology has made some progress in numerous aspects, significant challenges remain in terms of efficient cooling and practical applications. Herein, we report the preparation of a polyvinylidene fluoride (PVDF) composite film with a multiscale micro-nano structure, in which zirconia (ZrO₂) particles were bonded on the surface of the PVDF fibers via polydimethylsiloxane (PDMS). This PVDF composite film showed a relatively high solar reflectivity (>0.95) and excellent emissivity (>0.96) in the infrared atmospheric window, which resulted in a 21.8 °C and 10.4 °C temperature reduction compared to the simulated skin and ambient temperature under direct sunlight of about 1000 W m⁻², respectively. Meanwhile, the combination of the multistage structure and hydrophobicity property of PDMS resulted in superhydrophobicity with a hydrophobic angle of 155° and sliding angle of about 5°, thereby conferring the film with exceptional self-cleaning ability. Notably, PDMS simultaneously facilitated the formation of a bonding structure between the fibers, leading to enhanced mechanical properties. Compared to those of the PVDF electrospun film (F-S), the tensile strength and tensile strain of the designed composite film increased by 9.5 times and 4.4 times, respectively. Thus, the excellent performances of the PVDF composite film provide a great development prospect for the practical application of electrospun films in smart textiles and energy-saving.