Mark E. Lewittes

Novel thermal and photo curable anti-reflective coatings using fluoroelastomer nanocomposites and self-assembly of nanoparticles

We describe novel optical coatings which require either thermal or photocuring to render them mechanically robust and abrasion resistant. These new coatings are low refractive index fluoroelastomer-nanoparticle composites that form a unique nanostructure during drying of the liquid coating. During drying, the nanoparticles in these liquid coatings migrate towards the substrate. The final, 100-nm-thick anti-reflective coatings are novel and exhibit a unique bilayer structure in which the nanoparticles are ordered and segregated towards the substrate. The coatings are rapidly cured using a new process and exhibit surprising “scratch durability” as measured by aggressively testing with steel wool. Sol gel chemistry is used which involves the reaction of the nanoparticles with an acrylic oxysilane to form nanoparticles which are functionalized with sol gel derived oligomers. The functionalized nanoparticles are combined with a fluoroelastomer containing a free radical initiator and multiolefinic crosslinker, and the composite film is rapidly cured by a thermal or UV process at low temperatures. The final product is a mechanically robust, low refractive index anti-reflective film which is useful for displays and photovoltaic devices. These are unique fluoropolymer nanocomposites which utilize nanoparticle self-assembly to enhance important properties.