Abstract: In various embodiments, the present invention is directed to photothermal-responsive melanin-based nanocomposites comprising a plurality of natural or synthetic melanin nanoparticles distributed with a polymer matrix suitable for use in anti-counterfeiting, photothermal responsive-communication, sensors, and heat management, among other applications. In some embodiments, the present invention will be an ink, paint, or other coating comprising the photothermal-responsive melanin-based nanocomposites. In some embodiments, the present invention is directed to a written message or design comprising one or more of the photothermal-responsive melanin-based nanocomposites. In some of these embodiments, the written message or design will be comprised of two ore more of the photothermal-responsive melanin-based nanocomposites having different concentrations of natural or synthetic melanin nanoparticles.

Abstract: In one or more embodiments, the present invention provides a method of applying or printing structural colors to a substrate that involves pre-treatment of the substrate surface to prevent absorption of the fluid containing the particles. This allows the fluid to maintain their sessile drop shapes and as the water evaporates, the colloidal particles spontaneously assemble within the confined geometry into semi-ordered structures that interact with light to produce structural color. While the pre-treatment may be done in a variety of ways, application of a, hydrophobic and/or oleophobic coating, like 1H-IH,2H-perfluoro-1-dodecene (C10F21—CH?CH2) (perfluoro) monomer, fluoroalkyls, fluorohydroalkyls, cyclo-fluoroalkyls, fluorobenzen, by plasma-enhanced chemical vapor deposition (cold plasma treatment) has been found to be effective, particularly for printing applications. These treated substrates allow production of a wide range of structural colors using binary systems of nanoparticles.

Abstract: In one or more embodiments, the present invention provides a method of applying or printing structural colors to a substrate that involves pre-treatment of the substrate surface to prevent absorption of the fluid containing the particles. This allows the fluid to maintain their sessile drop shapes and as the water evaporates, the colloidal particles spontaneously assemble within the confined geometry into semi-ordered structures that interact with light to produce structural color. While the pre-treatment may be done in a variety of ways, application of a, hydrophobic and/or oleophobic coating, like 1H-IH,2H-perfluoro-1-dodecene (C10F21—CH?CH2) (perfluoro) monomer, fluoroalkyls, fluorohydroalkyls, cyclo-fluoroalkyls, fluorobenzen, by plasma-enhanced chemical vapor deposition (cold plasma treatment) has been found to be effective, particularly for printing applications. These treated substrates allow production of a wide range of structural colors using binary systems of nanoparticles.