One-step synthesis and self-assembly behavior of thermo-responsive star-shaped β-cyclodextrin–(P(MEO2MA-co-PEGMA))21 copolymers

A novel β-cyclodextrin-poly(2-(2-methoxyethoxy)ethyl methacrylate)- co -poly(ethylene glycol) methacrylate (abbreviated as: β-CD-(P(MEO 2 MA- 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(MEO 2 MA- co -PEGMA)) 21 copolymers were studied by FTIR, 1 H 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(MEO 2 MA- co -PEGMA) segments as a shell. These thermo-responsive starshaped copolymers micelles exhibited lower critical solution temperature (LCST) in water, which could be finely tuned by changing the feed ratio of MEO 2 MA to PEGMA. The LCST of star-shaped β-CD-(P(MEO 2 MA- 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(MEO 2 MA- co -PEGMA)) 21 star-shaped copolymer micelles could be potentially applied in nano-carrier, nano-reactor, smart materials and biomedical fields.