Organobase-Catalyzed Carboxyl-yne Click Polymerization

Polyesters have been widely used in the biological and engineering fields. However, the polycondensations used require high reaction temperatures and long reaction times, and the ring-opening polymerizations are generally intolerant to functional groups. Therefore, the development of a new polymerization toward polyesters under mild reaction conditions will further promote their development. In this work, we established a new organobase-catalyzed click polymerization of ester-activated alkynes and bis(carboxylic acid)s under mild reaction conditions, and regio- and stereoregular poly(β-acyloxyacrylate)s with weight-average molecular weights up to 24200 were obtained in yields up to 96%. The resultant polymers show versatile properties. The aliphatic poly(β-acyloxyacrylate)s exhibit crystalline behavior, whereas the aromatic polymers demonstrate high thermal stability. The polymer containing tetraphenylethene units exhibits the trade-off of high refractive index and Abbé Number. Thanks to the dynamic nature of β-acyloxyacrylate units, the resultant polymers could be quickly degraded upon addition of phenol derivatives and organobase, which could be applied in the fabrication of fluorescent photopatterns. Thus, this work not only provides a powerful polymerization toward polyesters and a facile reaction for postmodification of the materials containing carbonyl groups, but also enriches the family of X-yne click polymerization.