Long-Lived Multilayer Coatings for Smart Windows: Integration of Energy-Saving, Antifogging, and Self-Healing Functions

The air-conditioner (AC) system consumes much of the power of electric vehicles (EVs), which limits the EVs’ operating mileage. Automobile glasses coated with multifunctional thin films, which are antifogging, thermochromic, and self-healing, would hold a great promise for improving the EVs’ performance by reducing the AC load. In this work, a novel multifunctional multilayer thin film was designed and simply deposited by dip-coating method. The coating was composed of four layers in the following order: antireflective hollow SiO 2 layer (HSi), thermochromic VO 2 layer (V), protective fluorosilane–SiO 2 layer (FSi), and antifogging cross-linked poly(vinyl alcohol) and poly(acrylic acid) layer (P). The multilayer coating shows excellent solar regulation efficiency (Δ T sol = 16.4%), an appropriate luminous transmittance ( T lum-a = 54.0%), and excellent antifogging and self-healing properties, as well as impressive stability. This work presents an inexpensive and reliable approach for preparing highly stable energy-saving, antifogging, and self-healing multifunctional films for smart energy-saving windows.