Colorfully coated cotton fabric for passive daytime radiative cooling

Passive daytime radiative cooling (PDRC), which can cool objects without energy consumption, is a promising strategy for realizing sustainable cooling. However, developing radiative cooling materials with esthetic versatilities is still a great challenge, let alone colorful fabrics with cooling properties. Herein, we fabricate a colored radiative cooling cotton fabric by using a facile and scalable spraying strategy. Randomly distributed silane modified SiO2 serves as the backscattering underlayer exhibiting both high solar reflection and broadband mid-infrared emission. Acrylate polymers used to encapsulate pigments improve the pigment adhesion without sacrificing their spectral properties, and the encapsulated pigments cover on the underlayer as a colored layer to generate specific color. Consequently, the colored coated cotton fabric achieves a relatively high near infrared reflectance of 89 % and an atmospheric window emissivity of 91 %. Cooling effects are achieved by the colored coated cotton fabrics, which yield temperature drop of 5.6 °C comparing with bare cotton fabric and have lower temperatures of 2.5–4.7 °C than their contrast fabrics of the same color. In addition, the colored coated cotton fabrics have general moisture permeability, abrasion resistance, excellent mechanical strength and anti-ultraviolet intrusion ability.