Precise synthesis of a rod-coil type miktoarm star copolymer containing poly(n-hexyl isocyanate) and aliphatic polyester

Abstract

Well-defined hydroxyl end-functionalized poly(n-hexyl isocyanate), PHIC–(OH)₂ and PHIC–(OH)₃, as rod-type macroinitiators were synthesized by the Cu-catalyzed azide–alkyne cycloaddition reactions of azido end-functionalized PHIC with ethynyl alcohol derivatives. The PHIC–(OH)₂ and PHIC–(OH)₃ were suitable macroinitiators for the ring-opening polymerization of L-LA and ε-CL leading to the synthesis of novel rod-coil type miktoarm star copolymers, PHIC-b-PLLA₂, PHIC-b-PLLA₃, PHIC-b-PCL₂, and PHIC-b-PCL₃, with controlled molecular weights, narrow polydispersities, and controlled arm numbers. Additionally, the thermal and solution properties of the obtained miktoarm star copolymers along with the corresponding block copolymers, PHIC-b-PLLA and PHIC-b-PCL, were characterized by TGA, DSC, and DLS analyses.