Solubilization of Phenol Derivatives in Polymer Micelles Formed by Cationic Block Copolymer

Abstract

The aggregation of cationic block copolymers formed by polystyrene (PS) and poly(ethyl-4-vinylpyridine) (PS-b-PE4VP) was studied in aqueous solution. Diblock copolymers of PS and poly(4-vinylpyridine) were synthesized by sequential anionic polymerization using BuLi as initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PS-b-PE4VP block copolymers with different quaternization degree. The self-aggregation of cationic block copolymers was studied by fluorescence probing, whereas the morphology and size of polymer micelles were determined by transmission electronic microscopy. Results indicate that spherical micelles with sizes lower than 100 nm were formed, whereas their micropolarity decreases with increasing quaternization degree. The partition of phenols between the micellar and aqueous phase was studied by using the pseudo-phase model, and the results show that the partition coefficients increase with increasing length of the side alkyl chain and are larger for star micelles. These results are discussed in terms of three-region model.

Iron(III) porphyrin catalyzed ionic liquid mediated polymerization of methylmethacrylate

“…However, these enzymes show low stability under non − physiological conditions, and are relatively expensive, whereas metalloporphyrins are stable, inexpensive and relatively more promising for various applications . Apart from enzymatic polymerization, various other strategies have been employed for the polymerization reactions such as ring opening metathesis polymerization (ROMP), free radical (along with nanoconfinement), living radical, atom transfer radical, nitroxide‐mediated (NMP), reverse addition fragmentation, electrochemical, coordination, block and statistical polymerization, but harsh reaction conditions such as corrosive chemicals, prolonged reaction time and prolonged heating were employed in all these methods. Hence, mild conditions were required for the synthesis of polymer products.…”