%0 Journal Article
%T Synthesis of High Molecular Weight Cyclic Poly(ε-caprolactone)s of Variable Ring Size Based on a Light-Induced Ring-Closure Approach.
%A Wang H
%A Zhang L
%A Liu B
%A Han B
%A Duan Z
%A Qi C
%A Park DW
%A Kim I
%J Macromol Rapid Commun
%V 36
%N 18
%D Sep 2015
%M 26174587
%F 5.006
%R 10.1002/marc.201500171
%X High molecular weight cyclic poly(ε-caprolactone)s (cPCLs) with variable ring size are synthesized via light-induced ring closure of α,ω-anthracene-terminated PCL (An-PCL-An). The ring size of cPCL is tunable simply by adjusting the polymer concentration from 10 to 100 mg mL(-1) in THF. The cyclo-addition via the bimolecular cyclization of An-PC-An is well characterized by a variety of analyses such as (1) H NMR and UV-vis spectroscopies, gel-permeation chromatography, and differential scanning calorimetry. The reversible dimerization of An induced by heating enables the cyclic PCL to have a switchable "on-off" capability. This novel light-induced ring-closure technique can be one of the most powerful candidates for producing various well-defined cyclic polymers in highly concentrated polymer solution.