Ultrasonication-Induced Aqueous Atom Transfer Radical Polymerization

Abstract

A new procedure for ultrasonication-induced atom transfer radical polymerization (sono-ATRP) in aqueous media was developed. Polymerizations of oligo(ethylene oxide) methyl ether methacrylate (OEOMA) and 2-hydroxyethyl acrylate (HEA) in water were successfully carried out in the presence of ppm amounts of CuBr 2 catalyst and tris(2pyridylmethyl)amine ligand when exposed to ultrasonication (40 kHz, 110 W) at room temperature. Aqueous sono-ATRP enabled polymerization of watersoluble monomers with excellent control over the molecular weight, dispersity, and high retention of chain-end functionality. Temporal control over the polymer chain growth was demonstrated by switching the ultrasound on/off due to the regeneration of activators by hydroxyl radicals formed by ultrasonication. The synthesis of a well-defined block copolymer and DNA− polymer biohybrid was also successful using this process.

Free-Radical Graft Polymerization onto Starch as a Tool to Tune Properties in Relation to Potential Applications. A Review

“…In addition variations on ATRP, such as ARGET-ATRP (activators regenerated by electron transfer [51] and ICAR-ATRP (initiators for continuous activator regeneration ATRP) [52], which make use of significantly lower amount of copper, seem promising from an industrial point of view. Very recently, an ultrasound-induced ATRP, also making use of very small amount of copper catalyst, has been reported by Matyjaszewski's group [53].…”

Polymernetzwerke: Von Kunststoffen und Gelen zu porösen Gerüsten

“…Auf ähnliche Weise – und an das lichtinduzierte Wachstum von Strängen in Polymernetzwerken (siehe Abschnitt 3.3.4) zur Verfestigung von Netzwerken erinnernd – wurde die zufällige homolytische Spaltung von kovalenten Bindungen, die nach übermäßiger Belastung des Polymernetzwerks erfolgt, für die induzierte Selbstheilung des Netzwerks durch das Wachsen neuer Polymerstränge genutzt . Außerdem wurden piezoelektrische Materialien wie Zinkoxid oder selbst Wasser, die freie Radikale als Reaktion auf Schwingungen mit hoher Frequenz und kleiner Amplitude (z. B. Ultraschall) bilden können, zur Steuerung des Polymerwachstums verwendet; diese Strategie könnte eine weitere Möglichkeit zur Entwicklung von selbst‐verfestigenden Netzwerken sein.…”

Synthesis of Riboflavin‐Based Macromolecules through Low ppm ATRP in Aqueous Media

“…It can be triggered by the introduction of a reducing compound, for example, radical initiator in initiators for continuous activator regeneration (ICAR) ATRP, chemical reducing agents (e.g., glucose, ascorbic acid, hydrazine), and metallic silver in activators regenerated by electron transfer (ARGET) ATRP, zerovalent metals (Fe 0 , Cu 0 ) in supplemental activator and reducing agent (SARA) ATRP. Alternatively, an external stimuli such as a reducing current in electrochemically mediated ATRP ( e ATRP) and simplified electrochemically mediated ATRP ( se ATRP), light in photo‐induced ATRP (photo‐ATRP), or mechanical forces in mechanically induced ATRP (mechano‐ATRP) and in ultrasonication‐induced ATRP (sono‐ATRP) can be applied . Electrochemistry offers additional opportunity to catalyst recycle, eliminates needs for chemical reducing agents, provides temporal control during the process, and extends polymerization to aqueous media .…”