Patterning organosilane self-assembled monolayers, block copolymer lithography and thin film behavior, and the photoinduced formation of polymer brushes and monolayers

The chemical diversity and physical robustness of organosilane self-assembled monolayers (SAMs) makes them suitable for a variety of applications requiring the control of surface properties. This research has focused on the development of new techniques for micro- and nanopatterning functionalized organosilane SAMs, as well as the chemical modification of SAMs using photoinitiated systems.; Organosilane SAMs were micropatterned using standard photoresist-based lithographic and plasma etching techniques. Etched regions were backfilled with a second SAM containing a different organic substituent. By repeating the patterning process, a complex, multi-functional patterned surface composed of three different SAMs (amino-, methyl-, and thiol-terminated) was formed.; Solvent vapor annealing is shown to be a useful technique for controlling the formation of block copolymer film nanostructures. In the poly(isoprene-b-styrene) (PI-b-PS) system studied, MEK provides a useful hexagonal-type structure (78 nm repeat distance), while toluene yields a disordered nanostructure. By modifying the substrate with a low surface energy SAM, the development of regions with a high degree of hexagonal order was observed.; Using the hexagonal block copolymer arrays as templates, block copolymer lithography was used to nanopattern well-separated holes into organosilane SAMs on glass. Following the etching of holes into the SAM surface, a second SAM of different chemistry was deposited. In one experiment, holes in an amino-terminated SAM appeared to be filled with islands of a methyl-terminated SAM in scanning probe microscopy images. However, further experiments did not provide positive confirmation of the backfilling of a SAM into the nanopatterned holes.; The chemical modification of thiol-terminated SAMs using photoinitiated, thiol-ene systems was also investigated. Thin thiol-ene polymer brushes were formed by simply photopolymerizing a linear thiol-ene system in contact with a thiol-termated SAM surface. Although the thiol-ene brushes are thin, ranging from 0.1 to 5.7 nm, the thickness is linearly related to the molecular weight of the polymer formed in the bulk. Additionally, the photoinduced coupling of vinyl ether and vinyl silazane species to thiol-terminated organosilane SAMs is presented. With only enes present in the bulk, very thin films of near monolayer thickness are prepared, with or without photoinitiator.