Facile synthesis and controlled self-assembly of poly(phenyl isocyanide)-block-polycarbonate copolymers

Abstract

Although nanostructured block copolymers are very important and interesting, their convenient synthesis and controlled hierarchical self-assembly at high-order scales remain formidable challenges. In this study, poly(phenyl isocyanide)-block-polycarbonate copolymers were facilely synthesized using both stepwise and one-pot polymerizations. First, a hydroxyl-functionalized alkyne-Pd(II) (Pd(II)-OH) initiator was designed and synthesized. The Pd(II) moiety of Pd(II)-OH catalyzes the living polymerization of phenyl isocyanides, while the terminal hydroxyl unit initiates the ring-opening polymerization of cyclic carbonates. Then, block copolymers, possessing the desired molar mass (M_n) and narrow dispersity (M_w/M_n) distribution, were prepared using both stepwise and one-pot controlled polymerizations of two types of phenyl isocyanides and carbonates with Pd(II)-OH, respectively. By leveraging both synthesis methods, amphiphilic block copolymers containing hydrophilic poly(phenyl isocyanide)s and hydrophobic crystallizable polycarbonates were readily prepared. Furthermore, the crystallization-driven self-assembly (CDSA) of these amphiphilic block copolymers formed nanospheres, one-dimensional nanofibers, and two-dimensional nanoribbons possessing controlled widths and lengths and a narrow dispersity distribution, respectively.