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

Abstract

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.

Keywords:

• β-cyclodextrin
• Core-shell structure
• Hyperbranched
• PDMAEMA
• Temperature-responsive Property

Acknowledgments

We are grateful to the NSFC (20874080/21004049), the CPSF for Specialized Foundation (201003684), the NSBRP in Shaanxi Province (2010JQ2002), the Basic Scientific Research Foundation of NPU (JC200920/JC201156), and the Aero-science Foundation of China (2009ZH53073) for financial support. J. Kong sincerely thanks the “New Staff & Res. Area” project and “Soar Star” project of NPU for their support.