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Tailored (Bio)Interfaces via Surface Initiated Polymerization: Control of Grafting Density and New Responsive Diblock Copolymer Brushes
Author(s) -
Lilge Inga,
Steuber Marc,
Tranchida Davide,
Sperotto Elena,
Schönherr Holger
Publication year - 2013
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201350607
Subject(s) - atom transfer radical polymerization , copolymer , polymer chemistry , materials science , polymerization , polymer brush , radical polymerization , polymer , methacrylate , contact angle , acrylate , reversible addition−fragmentation chain transfer polymerization , ethylene glycol , chemical engineering , chain transfer , composite material , engineering
Summary Polymer brush synthesis by surface initiated polymerization (SIP) comprises a powerful strategy to tailor interfacial properties. Among others, the passivation of solid substrates against non‐specific protein adsorption or the implementation of stimuli responsive properties can be achieved. In this context controlled radical polymerization approaches are frequently employed. Here we report on our efforts in the synthesis of oligo and di(ethylene glycol) methylether methacrylate (OEGMA and DEGMA)‐based brushes with ( i ) controlled grafting density and ( ii ) new diblock copolymer structures. We assembled mixed self‐assembled monolayers (SAMs) comprising octadecanethiol (ODT), 16‐mercaptohexadecanoic (MHDA) and ω‐mercaptoundecyl bromoisobutyrate (MUBiB) on gold to initiate the controlled radical polymerization of OEGMA and DEGMA. The SAMs as well as the polymer layers obtained by atom transfer radical polymerization for a constant polymerization time were characterized by contact angle measurements with water, FTIR spectroscopy, ellipsometry and atomic force microscopy (AFM). It was found that ODT and MHDA assemble in the mixed SAMs preferentially and despite the different endgroups very similar brushes were obtained. SAMs with fractional surface coverages of the initiator ω‐mercaptoundecyl bromoisobutyrate of > 0.45 showed no further increase in brush thickness, which is in line with a mushroom to brush transition below this coverage. In addition, diblock copolymer brushes comprising POEGMA and poly( tert ‐butyl acrylate) (P t BA) blocks were obtained for the first time. The P t BA block was successfully hydrolyzed to yield POEGMA‐ block ‐poly acrylic acid (PAA) brushes.