Triple‐functional riboflavin‐based molecule for efficient atom transfer radical polymerization in miniemulsion media
Izabela Zaborniak, Karolina Surmacz, Monika Flejszar, Paweł Chmielarz
Abstract
Abstract Triple‐functional riboflavin‐based macromolecule was synthesized providing an efficient activator regeneration by electron transfer atom transfer radical polymerization of butyl acrylate in a miniemulsion media in a fully oxygen tolerant environment. For the first time, the riboflavin‐inspired supramolecular structure fulfilled three primarily roles, acting simultaneously as (a) an initiator due to incorporation of bromine molecules in a ribitol tail by esterification reaction of riboflavin with α‐bromoisobutyryl bromide; (b) a reducing agent caused by the preservation of redox functionality of isoalloxazine ring in this structure; (c) and enables polymerization in air conditions. Electrochemical characterization of the riboflavin‐based molecule was conducted by a series of cyclic voltammetry measurements, determining an activation rate constant ( k a = [1.34 ± 0.58] × 10 3 M −1 s −1 ) reflecting a reduction of the copper(II) catalytic complex in the presence of the multifunctional initiator. Proposed reaction system allowed to maintain control during polymerization proved by linear kinetics and a clear shift in molecular weights, resulting in the preparation of polymer brushes with narrow molecular weight distribution ( M w / M n = 1.39) with high initiation efficiency ( ƒ i = 72%).