Vapor-condensation-assisted reverse display for anti-counterfeiting applications

We propose a simple yet effective method for the display based on vapor condensation on the hydrophilic/hydrophobic patterned surfaces. It was found that supersaturated water vapor first formed nanometer-sized water droplet on the condensation nuclei on the patterned surfaces, then the water droplet grew bigger and therefore scatter more light to visualize the outline of the patterns for naked eyes. This vapor-condensation-assisted display is applicable to a variety of substrates from Si wafers, glass to mirrors. This method does not induce impurities and essentially low-cost and efficient, which may inspire interesting applications in various fields.