One-step synthesis and self-assembly behavior of thermo-responsive star-shaped β-cyclodextrin--(P(MEO ₂MA-co-PEGMA))₂₁ copolymers

Abstract

A novel β-cyclodextrin–poly(2-(2-methoxyethoxy)ethyl methacrylate)-co-poly(ethylene glycol) methacrylate (abbreviated as: β-CD–(P(MEO₂MA-co-PEGMA))₂₁) was prepared by using the one-step strategy, and then the star-shaped copolymers were used in the atom transfer radical polymerization (ATRP). The structure of star-shaped β-CD–(P(MEO₂MA-co-PEGMA))₂₁ copolymers were studied by FTIR, ¹H NMR and gel permeation chromatography (GPC). The star-shaped copolymers could self-assembled into micelles in aqueous solution owing to the outer amphiphilic β-CD as a core and the hydrophilic P(MEO₂MA-co-PEGMA) segments as a shell. These thermo-responsive star-shaped copolymers micelles exhibited lower critical solution temperature (LCST) in water, which could be finely tuned by changing the feed ratio of MEO₂MA to PEGMA. The LCST of star-shaped β-CD–(P(MEO₂MA-co-PEGMA))₂₁ copolymer micelles were increased from 35°C to 58°C with the increasing content of PEGMA. The results were investigated by DLS and TEM. When the temperature was higher than corresponding LCSTs, the micelles started to associate and form spherical nanoparticles. Therefore, β-CD–(P(MEO₂MA-co-PEGMA))₂₁ star-shaped copolymer micelles could be potentially applied in nano-carrier, nano-reactor, smart materials and biomedical fields.

Keywords

star-shaped copolymers / thermo-responsive / β-cyclodextrin (β-CD) / self-assembly / atom transfer radical polymerization (ATRP)

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