Thermochromic Properties of VO2-PVP Composite Coatings

Large surface and chemically stable thermochromic composite coatings consisting of IR active sub-micron VO2 particles embedded in a passive polymeric host matrix of Polyvinylphenol were synthesized by dip and spin coating process. The hybrid composite coatings are IR transparent and IR reflective below and above the switching temperature of ∼68 °C. Although these cost effective hybrid composite coatings are two-dimensional morphologically (1 to 3 non percolated submicron VO2 crystallites within the coating thickness), they exhibit a significant reversible IR transmission modulation with temperature of ∼45% between 25 °C and 100 °C at 1 μm.