title: Robust Thick Polymer Brushes Grafted from Gold Surfaces Using Bidentate Thiol-Based Atom-Transfer Radical Polymerization Initiators.
abstract: A new bromoisobutyrate-terminated alkanethiol, 16-(3,5-bis(mercaptomethyl)phenoxy)hexadecyl 2-bromo-2-methylpropanoate (BMTBM), was designed as a bidentate adsorbate to form thermally stable bromoisobutyrate-terminated self-assembled monolayers (SAMs) on flat gold surfaces to conduct atom-transfer radical polymerizations (ATRPs). The monolayers derived from BMTBM were characterized by ellipsometry, X-ray photoelectron spectroscopy (XPS), and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) and compared to the monolayers formed from 16-mercaptohexadecyl 2-bromo-2-methylpropanoate (MBM), 16-(3-(mercaptomethyl)phenoxy)hexadecyl 2-bromo-2-methyl-propanoate (MTBM), and octadecanethiol (C18SH). In this study, although the monolayer derived from BMTBM was less densely packed than those derived from MBM and MTBM, the bidentate adsorbates demonstrated much higher thermal stability in solution-phase thermal desorption tests, owing to the "chelate effect". The enhanced stability of the BMTBM SAMs ensured the development of thick brushes of poly(methyl methacrylate) and polystyrene at elevated temperatures (60, 90, 105, and 120 °C). In contrast, SAMs derived from MBM and MTBM failed to grow polymer brushes at temperatures above 100 °C.
authors: Department of Chemistry and the Texas Center for Superconductivity, University of Houston , 4800 Calhoun Road, Houston, Texas 77204-5003, United States.
authors: Chul Soon
authors: CS
authors: Park
authors: Department of Chemistry and the Texas Center for Superconductivity, University of Houston , 4800 Calhoun Road, Houston, Texas 77204-5003, United States.
authors: Han Ju
authors: HJ
authors: Lee
authors: Department of Chemistry and the Texas Center for Superconductivity, University of Houston , 4800 Calhoun Road, Houston, Texas 77204-5003, United States.
authors: Andrew C
authors: AC
authors: Jamison
authors: Department of Chemistry and the Texas Center for Superconductivity, University of Houston , 4800 Calhoun Road, Houston, Texas 77204-5003, United States.
authors: T Randall
authors: TR
authors: Lee
keywords: ATRP; PMMA; PS; SAMs; chelate effect; polymer brushes; thermal stability