High-efficiency preparation of macrocyclic diblock copolymers via selective click reaction in micellar media.
We report a novel strategy for the high-efficiency preparation of macrocyclic diblock copolymers at relatively high concentrations via the combination of supramolecular self-assembly and "selective" click reactions, relying on the fine control of spatial accessibility between terminal reactive groups. The linear precursor, alpha-alkynyl-omega-azido heterodifunctional poly(2-(2-methoxyethoxy)ethyl methacrylate)-b-poly(oligo(ethylene glycol) methyl ether methacrylate), linear-PMEO(2)MA-b-POEGMA-N(3), self-assembles into micelles with PMEO(2)MA cores and POEGMA coronas at elevated temperatures. The spatial separation between reactive alkynyl and azide groups precludes click reactions within micelle entities. On the other hand, due to the unimer-micelle exchange equilibrium and the fact that unimer concentration is typically low (critical micellization concentration, CMC), click reactions occur exclusively for unimers. This eventually led to complete intramolecular cyclization of all linear precursors.
Ge
Zhishen
Z
Hefei National Laboratory of Physical Sciences at the Microscale, CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China.
Zhou
Yueming
Y
Xu
Jian
J
Liu
Hewen
H
Chen
Daoyong
D
Liu
Shiyong
S