Double stimuli responsive mixed aggregates from poly(acrylic acid)-block-poly(ε-caprolactone)-block-poly(acrylic acid) and poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) triblock copolymers

Abstract Well defined ABA triblock copolymer comprising a biodegradable poly(ε-caprolactone) (PCL) middle block and two pH responsive poly(acrylic acid) (PAA) outer blocks was synthesized by atom transfer radical polymerization of tert-butyl acrylate, initiated by PCL-based macroinitiator, followed...
Ausführliche Beschreibung

Abstract Well defined ABA triblock copolymer comprising a biodegradable poly(ε-caprolactone) (PCL) middle block and two pH responsive poly(acrylic acid) (PAA) outer blocks was synthesized by atom transfer radical polymerization of tert-butyl acrylate, initiated by PCL-based macroinitiator, followed by selective hydrolysis of the poly(tert-butyl acrylate) blocks. The cooperative self-assembly of the synthesized poly(acrylic acid)-block-poly(ε-caprolactone)-block-poly(acrylic acid) ($ PAA_{22} %$ PCL_{26} %$ PAA_{22} $) copolymer with a temperature-responsive poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) ($ PEO_{26} %$ PPO_{40} %$ PEO_{26} $, Pluronic P85) triblock copolymer at different compositions in aqueous media was investigated. Based on experimental data, copolymer properties and composition, formation of nano-sized aggregates comprising a mixed PCL/PPO core and a mixed PEO/PAA corona is suggested. The binary mixture of $ PAA_{22} %$ PCL_{26} %$ PAA_{22} $:$ PEO_{26} %$ PPO_{40} %$ PEO_{26} $ copolymers at molar ratio 3:1 favors the formation of mixed aggregates only, while at higher $ PEO_{26} %$ PPO_{40} %$ PEO_{26} $ content the aggregates coexist with pure $ PEO_{26} %$ PPO_{40} %$ PEO_{26} $ micelles. Ausführliche Beschreibung