Three-dimensional porous nanocomposite cooling film and method of preparing the same

A method for preparing a three-dimensional porous nano composite cooling film in large scale, comprising the following steps:

• S1, weighing and mixing a certain amount of water and acetone in a volume ratio of water to acetone of 1:20 to form a mixed solvent;
• S2, dissolving a certain amount of cellulose acetate in the mixed solvent to form a transparent precursor solution;
• S3, synthesizing nano microspheres having a uniform size by Stober process, separating by centrifugation to obtain nano microspheres, subjecting the nano microspheres to a washing with deionized water, and then a drying under vacuum at 70° C. to obtain pre-dried nano microspheres;
• S4, dispersing the pre-dried nano microspheres in the precursor solution through stirring by a magnetic mixer at a speed of 400-600 r/min for 4-6 h to form a milky white suspension;
• and
• S5, putting the milky white suspension to a casting machine, and subjecting the milky white suspension to a natural volatilization to obtain a large-area cellulose acetate/nano microspheres composite cooling film, wherein the composite cooling film has a controllable thickness.