Radiative cooling paints comprising different sized baso4 particles

A method of making a sprayable radiative cooling paint, comprising:

• obtaining a first quantity of BaSO4 powder having a hydrodynamic size distribution with an average particle size of about 1638 nm;
• grinding, in a ball milling machine, a second quantity of BaSO4 powder for about two hours until the second quantity has a second hydrodynamic size distribution with an average particle size of about 326 nm;
• grinding, in a ball milling machine, a third quantity of BaSO4 powder for about six hours until the third quantity has a third hydrodynamic size distribution with an average particle size of about 183 nm;
• grinding, in a ball milling machine, a fourth quantity of BaSO4 powder for about ten hours the fourth quantity has a fourth hydrodynamic size distribution with an average particle size of about 151 nm;
• grinding, in a ball milling machine, a fifth quantity of BaSO4 powder for about twenty-four hours until the fifth quantity has a fifth hydrodynamic size distribution with an average particle size of about 137 nm;
• grinding, in a ball milling machine, a sixth quantity of BaSO4 powder for about forty-eight hours until the sixth quantity has a sixth hydrodynamic size distribution with an average particle size of about 53 nm is obtained;
• and
• forming a first sprayable radiative cooling paint, a second sprayable radiative cooling paint, a third sprayable radiative cooling paint, a fourth sprayable radiative cooling paint and a fifth sprayable radiative cooling paint by mixing, in a mixer, in an amount of about 25 wt. %, combinations of each of the first quantity of BaSO4 powder, the second quantity, the third quantity, the fourth quantity, the fifth quantity and the sixth quantity, respectively, with about 25 wt. % of polyacrylic binder and about 50 wt. % of deionized water, ultrasonicating, in an ultrasonicator, each sprayable radiative cooling paint and mixing, by a roller mixer, each sprayable radiative cooling paint for about twenty-four hours.