Light-Mediated Formation of Reactive Surface Chemical Patterns Using Thermally Crosslinkable Photosensitive Copolymers

We demonstrate the photoinduced formation of a surface reactive functionality on thermally crosslinked thin films of random copolymers consisting of glycidyl methacrylate (GMA), o-nitrobenzyl derivative (NBOCMA), and styrene monomers, namely poly(S-r-GMA-r-NBOCMA). The photolabile o-nitrobenzyl moiety in the thin films released primary amine group upon UV light illumination. The amount of the light energy imparted to the thin film was varied to control the concentration of the generated amine, thus modulating effective surface chemical composition. This change in the composition shifted the surface wettability toward being more hydrophilic. Utilizing the reactivity of released primary amine, the arrays of green fluorophore were fabricated on micrometer-scale patterns, well-defined by the typical photolithographic technique. Our studies highlight the potential of the photodeprotection chemistry as a simple but effective route to control the placement of a specific functionality in thin films, which can be further extended to achieve surface active materials with highly complex functionalities.