The present invention provides a method for preparing a material in the form of liquid for forming an antimicrobial surface coating with multi-level antimicrobial properties, comprising: encapsulating one or more volatile or gaseous biocides in two or more amphiphilic block copolymers to obtain a w/o/w double emulsion, and mixing the w/o/w double emulsion with one or more nonvolatile biocides, each of which is selected from the group consisting of a metal containing biocide, triclosan, a carboxylic acid, a sugar acid and a combination thereof.
