Chang-Geun Chae

Arrangement of C60 via the self-assembly of post-functionalizable polyisocyanate block copolymer.

Poly(furfuryl isocyanate) (PFIC), which includes the reactive furan group, was synthesized by anionic polymerization using a sodium benzhydroxide (Na-BH), self-assembly initiator. We determined the optimum polymerization conditions by varying both the reaction time and the molar ratio of the monomer to the initiator. Block copolymer, poly(furfuryl isocyanate)-b-poly(n-hexyl isocyanate), was synthesized under optimized polymerization conditions. The PFIC was modified by Diels-Alder reactions with C60 for functionalization. Transmission electron microscopy (TEM) was used to study the self-assembly of block copolymers and modified block copolymer with C60. C60 formed highly ordered aggregates on the PFIC domains via self-assembly of the block copolymer.

Living Anionic Polymerization of Isocyanates

Polyisocyanates are rodlike polymers with dynamic helical conformations likely to be synthesized using anionic polymerization. Although many scientists have tried to obtain polyisocyanates with a controlled molecular weight and a narrow weight distribution, the trimerization precluded controlled polyisocyanate formation. To overcome the lack of a living nature, special anionic polymerizations were invented. The use of effective additives and dual functional initiators stabilized the living chain end to prevent the trimerization. These polymerizations eventually achieved the living nature indicating quantitative yield and predictable molecular weight and narrow molecular weight distribution. The state of art of anionic polymerization of isocyanates and the effective functionalization techniques led to synthesis of well-defined linear, telechelic, chiral, star, rod-coil block, and graft polymers. From the controlled molecular architectures, a comprehensive understanding on helical properties and morphologies for polyisocyanates and their block copolymers has been accomplished.