title: Ultrasmooth Polydopamine Modified Surfaces for Block Copolymer Nanopatterning on Flexible Substrates.
abstract: Nature has engineered universal, catechol-containing adhesives which can be synthetically mimicked in the form of polydopamine (PDA). In this study, PDA was exploited to enable the formation of block copolymer (BCP) nanopatterns on a variety of soft material surfaces. While conventional PDA coating times (1 h) produce a layer too rough for most applications of BCP nanopatterning, we found that these substrates could be polished by bath sonication in a weakly basic solution to form a conformal, smooth (root-mean-square roughness ∼0.4 nm), and thin (3 nm) layer free of large prominent granules. This chemically functionalized, biomimetic layer served as a reactive platform for subsequently grafting a surface neutral layer of poly(styrene-random-methyl methacrylate-random-glycidyl methacrylate) to perpendicularly orient lamellae-forming poly(styrene-block-methyl methacrylate) BCP. Moreover, scanning electron microscopy observations confirmed that a BCP nanopattern on a poly(ethylene terephthalate) substrate was not affected by bending with a radius of ∼0.5 cm. This procedure enables nondestructive, plasma-free surface modification of chemically inert, low-surface energy soft materials, thus overcoming many current chemical and physical limitations that may impede high-throughput, roll-to-roll nanomanufacturing.
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Joon Hee
authors.initials: JH
authors.lastname: Cho
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Reika
authors.initials: R
authors.lastname: Katsumata
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Sunshine X
authors.initials: SX
authors.lastname: Zhou
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Chae Bin
authors.initials: CB
authors.lastname: Kim
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Austin R
authors.initials: AR
authors.lastname: Dulaney
authors.affiliation: Center for Devices and Radiological Health, U.S. Food and Drug Administration , 10903 New Hampshire Avenue, 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 , 200 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ellison
keywords: block copolymer (BCP); conformal coating; flexible substrates; nanopatterning; polydopamine (PDA); self-assembly; solution deposition; surface modification