Synthesis and characterization of dual stimuli-responsive triblock polyrotaxane based on cyclodextrin by ATRP

Abstract

Thermo- and pH-responsive polyrotaxane (PR)-based triblock copolymers were synthesized by atom transfer radical polymerization (ATRP) of N-isopropylacrylamide initiated with polypsudorotaxanes which were presynthesized from bromine end-capped poly(ethylene glycol)/poly(propylene glycol) with cyclodextrins in the presence of CuBr/HMDETA under near physiological conditions. The triblock copolymers were characterized by ¹H NMR, FT-IR, GPC (gel permeation chromatography) analyses. Thermo- and pH-responsive behavior evaluated by UV–Vis spectroscopies, DLS (dynamic light scattering), and TEM (transmission electron microscopy) images showed that its lower critical solution temperature (LCST) was slightly increased with increasing pH values due to hydroxyl groups of cyclodextrin depending on pH values.

Keywords:

• ATRP
• cylcodextrin
• PNIPAAm
• polyrotaxane
• triblock copolymer

Additional information

Funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [NRF-2017R1D1A1B04032465].