| 초록 |
We demonstrate the facile synthesis of ultra-small branched star polycaprolactone (USB-SPCL) with precisely controlled architecture via manipulating monomer-to-core ratio, adjusting monomer-to-polymer conversion, end-capping terminal group, and vacuum purification. The USB-SPCL exhibits a narrow molecular weight distribution (MWD) and a branching length of DP＜5. We thus investigate the effect of extremely small branchs on the dynamic of a star polymer using the well-defined USB-SPCL as a model system. Interestingly, the glass transition, viscoelasticity, and molecular motion of USB-SPCL depend on its total molecular weight regardless of the molecular architecture while the crystallization of USB-SPCL is thoroughly dependent on the end group concentration related to the molecular architecture. These show that USB-SPCL follows the Bueche-modified Rouse model for unentangled linear polymer rather than traditional star polymer. Moreover, USB-SPCL acts as a single coarse-grain unit. |
