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One Step ATRP Initiator Immobilization on Surfaces Leading to Gradient-Grafted Polymer Brushes

Bryan R Coad, Katie E Styan, Laurence Meagher

ACS Appl Mater Interfaces. 2014 May 28;6(10):7782-9.

PMID: 24783968

Abstract:

A method is described that allows potentially any surface to be functionalized covalently with atom transfer radical polymerization (ATRP) initiators derived from ethyl-2-bromoisobutyrl bromide in a single step. In addition, the initiator surface density was variable and tunable such that the thickness of polymer chain grafted from the surface varied greatly on the surfaces providing examples, across the surface of a substrate, of increased chain stretching due to the entropic nature of crowded polymer chains leading toward polymer brushes. An initiator gradient of increasing surface density was deposited by plasma copolymerization of an ATRP initiator (ethyl 2-bromoisobutyrate) and a non-ATRP reactive diluent molecule (ethanol). The deposited plasma polymer retained its chemical ability to surface-initiate polymerization reactions as exemplified by N,N'-dimethyl acrylamide and poly(ethylene glycol) methyl ether methacrylate polymerizations, illustrating linear and bottle-brush-like chains, respectively. A large variation in graft thickness was observed from the low to high chain-density side suggesting that chains were forced to stretch away from the surface interface--a consequence of entropic effects resulting from increased surface crowding. The tert-butyl bromide group of ethyl 2-bromoisobutyrate is a commonly used initiator in ATRP, so a method for covalent linkage to any substrate in a single step desirably simplifies the multistep surface activation procedures currently used.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP245070977 Poly(ethylene glycol) methyl ether 2-bromoisobutyrate Poly(ethylene glycol) methyl ether 2-bromoisobutyrate 245070-97-7 Price
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