Temperature-responsive Property of Star Poly((N,N-dimethylamino)ethyl methacrylate) with Hyperbranched Core: Effect of Core-Shell Architecture and β-Cyclodextrin GraftedviaCovalent Bond or Ionic Electrostatic Attraction

The influence of macromolecular architectures on temperature-responsive properties of poly((N,N-dimethylamino)ethyl methacrylate) (PDMAEMA) was investigated to control the lower critical solution temperature (LCST) for promoting its potential application in the biomedical field. Temperature-responsive property of PDMAEMA was adjusted via β-cyclodextrin (β-CD) groups on polymers, the hyperbranched architecture, and the core-shell structure. The effect of β-CD groups, hyperbranched architecture, and core-shell structure on LCST was accomplished by comparing the amphiphilic hyperbranched polymers with and without β-CD groups, as well as their linear analogous. The β-CD groups grafted via ionic electrostatic attraction can increase the LCST value of PDMAEMA at different pH value and ionic strength. In contrast, the covalent β-CD groups result in the decrease of LCST at a wide range of pH value. Additionally, the LCST value is also prominently determined by core-shell structure. The core layer carrying the covalent β-CD groups increases LCST value, whereas the shell layer containing 2-Hydroxyethyl methacrylate (HEMA) component decreases LCST value.