title: Orthogonally Spin-Coated Bilayer Films for Photochemical Immobilization and Patterning of Sub-10-Nanometer Polymer Monolayers.
abstract: Versatile and spatiotemporally controlled methods for decorating surfaces with monolayers of attached polymers are broadly impactful to many technological applications. However, current materials are usually designed for very specific polymer/surface chemistries and, as a consequence, are not very broadly applicable and/or do not rapidly respond to high-resolution stimuli such as light. We describe here the use of a polymeric adhesion layer, poly(styrene sulfonyl azide-alt-maleic anhydride) (PSSMA), which is capable of immobilizing a 1-7 nm thick monolayer of preformed, inert polymers via photochemical grafting reactions. Solubility of PSSMA in very polar solvents enables processing alongside hydrophobic polymers or solutions and by extension orthogonal spin-coating deposition strategies. Therefore, these materials and processes are fully compatible with photolithographic tools and can take advantage of the immense manufacturing scalability they afford. For example, the thicknesses of covalently grafted poly(styrene) obtained after seconds of exposure are quantitatively equivalent to those obtained by physical adsorption after hours of thermal equilibration. Sequential polymer grafting steps using photomasks were used to pattern different regions of surface energy on the same substrate. These patterns spatially controlled the self-assembled domain orientation of a block copolymer possessing 21 nm half-periodicity, demonstrating hierarchical synergy with leading-edge nanopatterning approaches.
authors.affiliation: Center for Devices and Radiological Health, U.S. Food and Drug Administration , Silver Spring, Maryland 20993, United States.
authors.forename: Dustin W
authors.initials: DW
authors.lastname: Janes
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Chae Bin
authors.initials: CB
authors.lastname: Kim
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Maher
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ellison
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D008298:Maleates / Q000737:chemistry*; D055668:Photochemical Processes; D011137:Polystyrenes / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D008051:Lipid Bilayers; D008298:Maleates; D011137:Polystyrenes; D013113:Spin Labels; C518261:poly(4-styrenesulfonic acid-co-maleic acid)