Due to the increasing requirement for more environmentally and industrially relevant approaches in macromolecules synthesis, ultrasonication‐mediated atom transfer radical polymerization (sono‐ATRP) in miniemulsion media is applied for the first time to obtain precisely defined poly(n‐butyl acrylate) (PBA) and poly(methyl methacrylate) (PMMA) homopolymers, and poly(n‐butyl acrylate)‐block‐poly(tert‐butyl acrylate) (PBA‐b‐PtBA) and poly(n‐butyl acrylate)‐block‐poly(butyl acrylate) (PBA‐b‐PBA) copolymers. It is demonstrated in the reaction setup with strongly hydrophilic catalyst copper(II) bromide/tris(2‐pyridylmethyl)amine (CuIIBr2/TPMA) responsible for two principal mechanisms – interfacial and ion‐pair catalysis reflecting single‐catalyst approach. This solution turns out to be an excellent tool in controlled preparation of well‐defined polymers with narrow molecular weight distribution (up to Ð = 1.28) and preserves chain‐end functionality (DCF = 0.02% to 0.32%). Temporal control over the polymer chain growth is successfully conducted by turning the ultrasonication on/off. Taking into consideration long OFF stage (92.5 h) during ultrasonication‐induced polymerization in miniemulsion, synthesis is efficiently reinitiated without any influence on controlled characteristics maintaining the precise structure of received PBA homopolymers, confirmed by narrow molecular weight distribution (Ð = 1.26) and high retention of chain‐end functionality (DCF = 0.01%). This procedure constitutes an excellent simple and eco‐friendly approach in preparation of functional polymeric materials.

The flavonoid-based macroinitiator was received for the first time by the transesterification reaction of quercetin with 2-bromoisobutyryl bromide. In accordance with the “grafting from” strategy, a naturally-occurring star-like polymer with a polar 3,3',4',5,6-pentahydroxyflavone core and hydrophobic poly(tert-butyl acrylate) (PtBA) side arms was synthesized via a simplified electrochemically mediated ATRP (seATRP), utilizing only 78 ppm by weight (wt) of a catalytic CuII complex. To demonstrate the possibility of temporal control, seATRP was carried out utilizing a multiple-step potential electrolysis. The rate of the polymerizations was well-controlled by applying optimal potential values during preparative electrolysis to prevent the possibility of intermolecular coupling of the growing polymer arms. This appears to be the first report using on-demand seATRP for the synthesis of QC-(PtBA-Br)5 pseudo-star polymers. The naturally-derived macromolecules showed narrow MWDs (Đ = 1.08–1.11). 1H NMR spectral results confirm the formation of quercetin-based polymers. These new flavonoid-based polymer materials may find applications as antifouling coatings and drug delivery systems.

Ultrasonic agitation is an external stimulus, rapidly developed in recent years in the atom transfer radical polymerization (ATRP) approach. This review presents the current state-of-the-art in the application of ultrasound in ATRP, including an initially-developed, mechanically-initiated solution with the use of piezoelectric nanoparticles, that next goes to the ultrasonication-mediated method utilizing ultrasound as a factor for producing radicals through the homolytic cleavage of polymer chains, or the sonolysis of solvent or other small molecules. Future perspectives in the field of ultrasound in ATRP are presented, focusing on the preparation of more complex architectures with highly predictable molecular weights and versatile properties. The challenges also include biohybrid materials. Recent advances in the ultrasound-mediated ATRP point out this approach as an excellent tool for the synthesis of advanced materials with a wide range of potential industrial applications.

A vitamin‐B2‐based macroinitiator is prepared by esterification of riboflavin with 2‐bromoisobutyryl bromide. Following the “core first” methodology, “phoenix”‐shape (co)polymers with a polar riboflavin core and either a hydrophobic (poly(n‐butyl acrylate) or poly(methyl methacrylate)) or hydrophilic (poly(N‐isopropylacrylamide)‐block‐poly(oligo(ethylene glycol) acrylate) or poly(N‐isopropylacrylamide)‐block‐poly(2‐hydroxyethyl acrylate)) tails are synthesized via low ppm atom transfer radical polymerization procedures. Polymers have predetermined molecular weights and a low dispersity (Ð < 1.2). 1H NMR analysis confirms the successful formation of targeted (co)polymers with the preserved riboflavin functionality.

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Inspired by tea stains, a plant polyphenolic‐based macroinitiator is prepared for the first time by partial modification of tannic acid (TA) with 2‐bromoisobutyryl bromide. In accordance with the “grafting from” methodology, a naturally occurring star‐like polymer with a polar gallotannin core and a hydrophobic poly(n‐butyl acrylate) side arms is synthesized via a simplified electrochemically mediated ATRP (seATRP), utilizing multiple‐step potential electrolysis. To investigate the kinetics of the electrochemical catalytic process triggered by reduction of Cu(II) or Fe(III) catalytic complex in the presence of the multifunctional initiator, cyclic voltammetry measurements are conducted. The naturally derived tannin macromolecule shows narrow MWDs (Đ = 1.57). Moreover, solvolysis of the star polymer to cleave the side arms and characterize them indicates that all chains grow to the same length (homopolymers with Mw/Mn <1.17), which confirms the well‐controlled seATRP. The structure of the obtained TA‐based systems is characterized microscopically (AFM) and spectroscopically (1H NMR, FT‐IR). Atomic force microscopy measurements precisely determine the diameters of the obtained star polymers (19.7 ± 3.3 nm). These new star polymers may find biomedical applications as drug delivery systems and antifouling or antimicrobial coatings.

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A novel supramolecular riboflavin-inspired macroinitiator was prepared for the first time by transesterification methodology and used as the multifunctional vitamin-B 2 core to synthesize PBA brushes using different low ppm atom transfer radical polymerization (ATRP) approaches. Firstly the macromolecular initiator was successfully applied as a dually-functional structure, which simultaneously acts as a reducing agent in activator regeneration by electron transfer (ARGET) ATRP. Subsequently simplified electrochemically mediated ATRP of BA with different conditions was carried out for the preparation of well-defined riboflavin-based polymer brushes. Polymerizations were characterized in a well-controlled manner, affording polymers with a narrow dispersity (Ð = 1.22-1.25). Four-arms polymers were also received by an approach never described before-temporally-controlled multi-step seATRP under constant current conditions, giving precisely-defined polymer brushes (Ð = 1.26) with preserved chain-end functionality (DCF < 1%), despite stopping and restarting the polymerization. The solvolysis results indicate that all chains grow to equal lengths (Ð < 1.17), which shows the precisely controlled characteristic of seATRP. 1 H NMR analysis confirms the formation of new vitamin B 2-inspired polymers. In connection with the preserved riboflavin functionality and additional functional chains, these innovative macromolecules may find applications, e.g. as drug delivery systems.