Preparation of onion-like multilayered particles comprising mainly poly(iso-butyl methacrylate)-block-polystyrene by two-step AGET ATRP

Abstract

Synthesis of multilayered composite polymer particles comprising mainly poly(iso-butyl methacrylate)-block-polystyrene (PiBMA-b-PS) has been carried out by use of two-step activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP) in aqueous microsuspension. PiBMA-Br macroinitiator seed particles were prepared in the first step, followed by swelling with styrene and subsequent second step (seeded) polymerization. The blocking efficiency in the second step was found to be crucial with regards to the resulting particle morphology. A disordered sea-island morphology was obtained when the blocking efficiency was 47% (73% conversion), whereas a blocking efficiency of 61% (71% conversion) resulted in formation of multilayered particles. High blocking efficiency can be achieved by careful adjustment of the activation rate by proper choice of polymerization temperature and amount of reducing agent (ascorbic acid).

Block copolymer synthesis by controlled/living radical polymerisation in heterogeneous systems

“…[94][95][96] In the initial study, the interior of near-symmetrical P i BuMA-b-PSt particles appeared onion-like, indicating phase separation into lamellar morphology, as expected based on volume fraction. 94 Results from the second study suggested an influence of blocking efficiency on phase separation.…”

“…95 St polymerisation rate was significantly enhanced in miniemulsion conditions, but block copolymer Đ was high (2.4) due to a significant quantity of homo-P i BuMA and low blocking efficiency (<50%). By measuring the fraction of living chains at different stages of polymerisation (using a GPC dual detection method), it became evident that a significant quantity of dead chains formed during the early A rigorous study into a range of ligands and surfactants for AGET ATRP was performed by Xue et al for the synthesis of PSt-b-P n BuA-b-PSt using a difunctional ATRP initiator.…”

Synthesis and characterization of a new fluorinated macroinitiator and its diblock copolymer by AGET ATRP

“…These results would provide an economical and facile method for the synthesis of fabricating fluorinated block copolymers. HFMA and IBMA were prepared according to the literature [31,34]. All other chemicals are used without further purification.…”

Low Ppm Atom Transfer Radical Polymerization in (Mini)Emulsion Systems

“…As opposed to the initial concept, a single hydrophilic complex can also catalyze miniemulsion eATRP, if the cationic copper complex has strong interaction with an anionic surfactant. The catalyst/surfactant system produces ion pairs at the droplet surface to transport the catalyst into monomer droplets, thus enabling a controlled polymerization, enhanced by interfacial catalysis [82,83]. Different combinations of surfactant and hydrophilic Cu complexes were studied in the miniemulsion eATRP of n-butyl acrylate [38].…”