Thermal insulating superhydrophobic composite coating for building thermal management

Thermal insulating coatings have important potential for energy saving in the field of building thermal management, but they are difficult to apply on a large scale due to the problem of being waterproof and moistureproof. Herein, we design a two-step spray process to fabricate a thermal insulating superhydrophobic composite coating using epoxy resin mixed with hollow glass microsphere as primer coating and fluorine-modified SiO₂ nanocoating as a waterproof layer. The composite coating shows durable superhydrophobicity and low thermal conductivity [0.051 W/(m·k)], which is endowed with excellent thermal insulating properties under light and heat, contact heat conduction (− 20 to 70 °C), and boiling water scouring environment. These multiple key properties that have been integrated into our composite film are expected to provide unique advantages for applications in building thermal management.