Evaluation of 2-Bromoisobutyryl Catechol Derivatives for Atom Transfer Radical Polymerization-Functionalized Polydopamine Coatings

Abstract

The use of α-bromoisobutyryl-functionalized polydopamine (PDA), derived from an in situ mixture with dopamine (DA) and α-bromoisobutyryl bromide, enables surface-initiated atom transfer radical polymerization (SI-ATRP) of a broad range of methacrylate monomers for surface functionalization. Although the putative intermediate 2-bromo-N-(3,4-dihydroxyphenethyl)-2methylpropanamide 1 has been proposed to account for the SI-ATRP activity of α-bromoisobutyryl-functionalized PDA, there has not been a systematic investigation on the efficacy of other catechol-derived 2-bromoisobutyryl derivatives for SI-ATRP. In this work, a number of catechol-derived ATRP initiators containing the 2-bromoisobutyryl moiety were designed and synthesized, in an effort to investigate the effect of changes in structure on initiator immobilization, and subsequent ATRP performance. The change in the length of the linker unit bearing the 2bromoisobutyryl moiety, the introduction of a free amine group, or the replacement of the amide with an ester were found to have profound effects on the ability of the molecule to deposit ATRP-initiator-modified PDA coatings, as well as the subsequent SI-ATRP performance. Among the ATRP initiators synthesized, 5-(2-aminoethyl)-2,3-dihydroxyphenethyl 2-bromo-2-methylpropanoate hydrobromide 4•HBr was most efficiently incorporated into ATRP-initiator-modified PDA coatings and also the best at effecting SI-ATRP with 2-hydroxyethyl methacrylate; the high performance of this initiator is likely due to the presence of a free amine and an appropriately long methylene linker unit to the 2-bromoisobutyryl moiety. This methodology was found to be suitable for the functionalization of a range of organic and inorganic surfaces, for the fabrication of high-value surface-grafted polymer brush coatings for various applications.

Design and Synthesis of Polyphenolic Imidazo[4,5-c]quinoline Derivatives to Modulate Toll Like Receptor-7 Agonistic Activity and Adjuvanticity

“…Demethylation , of compounds 11a – f were carried out using BBr 3 in dry CH 2 Cl 2 at inert atmosphere to give compounds 12a – f . Among the synthesized BBIQ derivatives, except compounds 11a , , 12a and 12b all the compounds are novel and are not reported in the literature.…”

Reversible Adsorption and Detachment of Saccharomyces cerevisiae on Thermoresponsive Poly(N-isopropylacrylamide)-Grafted Fibers for Continuous Immobilized Fermentation

“…Inspired by the biomimetic modification strategy of the DA self-polymerization technique, a thin film of PDA was used as a foundation for the CF. The scheme of ISI-ATRP is illustrated in Figure .…”

Synthesis and Properties of Hydrogels on Medical Titanium Alloy Surface by Modified Dopamine Adhesion

“…The advantage of this method is that the synthesis of the initiator and the adhesion to the substrate is a one-step synthesis, and the adhesion to the substrate is strong. Using a modified polydopamine film as an initiator on the surface of the substrate can form polymer brushes through polymerization, thereby modifying the surface of the substrate [ 28 , 29 , 30 ]. However, there are few reports on the formation of hydrogels on substrates based on functionalized polydopamine.…”