Synthesis and behaviour of PEG-b-PDEAm block copolymers in aqueous solution Auteur(s): Zhang Xuewei, Burton Tobias, In M., Begu Sylvie, Aubert-Pouëssel Anne, Robin Jean-Jacques, Monge Sophie, Giani Olivia (Article) Publié: Materials Today Communications, vol. 24 p.100987 (2020) Texte intégral en Openaccess : Ref HAL: hal-02507349_v1 DOI: 10.1016/j.mtcomm.2020.100987 WoS: 000571134300004 Exporter : BibTex | endNote Résumé: Well-defined double hydrophilic block copolymers (DHBCs) of poly(ethylene glycol)-block-poly(N,N-diethyla-crylamide) (PEG-b-PDEAm) were synthesized via a reversible addition-fragmentation chain-transfer (RAFT) polymerization of N,N-diethylacrylamide (DEAm) using dithioester terminated PEG of different chain lengths as macro-chain transfer agents. Controlled molecular weight and narrow molecular weight distribution were achieved as proven by size exclusion chromatography (SEC). Cloud points (CP) were determined via turbidity measurements with ultraviolet-visible spectroscopy (UV-vis) and LCST by differential scanning micro-calori-metry (micro-DSC). They range from 32 to 40°C depending on the PDEAm length block and its concentration. Above the LCST, fluorescence spectroscopy and dynamic light scattering (DLS) demonstrated that the PEG-b-PDEAm copolymers self-organized into large aggregates. More interestingly, copolymers pre-aggregated at relatively high concentrations below the LCST. |