UCLA researchers from the Department of Materials Science and Engineering have developed a composite surface, stimuli-responsive thin film capable of rapidly encrypting and decoding hidden messages and images.
Periodic structures have emerged as an attractive substitute for dyes and pigments in anti-counterfeiting applications because they are difficult to duplicate and resist fading. Typically, periodic structures are designed with colloids or liquid crystals which work to hide a message or image until application of an external stimuli (pH, temperature, light, magnetic field). Unfortunately, many of these systems fail to completely obscure the encrypted message, are often costly to fabricate, and are sensitive to mechanical perturbations. A more robust, cost-effective material is needed to enable widespread application of periodic structure security technology.
UCLA researchers have developed a reconfigurable composite surface that allows for complete, rapid encryption and decryption of messages and images. The surface responds to moisture, hiding the message or image in response to dehydration and revealing the image or message upon rehydration. The method is easily scalable using roll-to-roll imprinting or 3D printing and the image reveal response rate can be easily tuned based on surface composition and thickness. The method was successfully tested to completely encrypt/decrypt a message (<1 sec) for multiple cycles (>10).
Encryption, Anti-counterfeiting, Hydrogel, Epoxy, Moisture Responsive, Stimuli, Sensor, Security, Scalable, 3D Printing, Optics, Messages