Self-Assembled Molecular Coatings for Helmet Mounted Display Visors

This Phase I SBIR program will investigate the feasibility of using molecular self-assembly processes for the formation of spectral coatings on helmet mounted display visors. Electrostatic self-assembly (ESA) involves the simple and low-cost coating ofsolid substrates by the alternate adsorption of anionic and cationic complexes of polymers, metallic nanoclusters and other molecules from water-based solutions at room temperature and pressure. Each adsorption step adds a single uniform molecularmonolayer to the thickness of the total coating. By selecting the molecules incorporated into each of many successive monolayers, the index of refraction may be varied as a function of thickness through the coating, and spectral filter stacks may beformed. Advantages over conventional deposition processes include ability to form uniformly-thick coatings on arbitrarily-shaped substrates of virtually any size, and avoidance of high temperature processing which often either limits substrate choice orleads to unacceptable long-term mechanical performance for polymer-based substrates. During Phase I, NanoSonic will design and fabricate narrowband spectral filters on curved polycarbonate substrates, and evaluate spectral and mechanical properties of thecoated test articles. During Phase II, the filter fabrication process will be optimized to allow the low-cost batch coating of visors by an automated robotic coating system.Improved methods for the fabrication of spectral control coatings have defenseapplications in laser weapon protection, canopy and window coatings and stealth systems, and commercial applications for bulk optical components, microphotonic and optoelectronic device endfaces, and AR coatings for spectacle lenses and windows.