Solid State and Solution Self-Assembly of Helical Polypeptides Tethered to Polyhedral Oligomeric Silsesquioxanes

Abstract

New macromolecular self-assembling building blocks, polyhedral oligo- silsesquioxane (POSS)-helical polypeptide copolymers, have been synthesized through the ring-opening polymerization (ROP) of gamma-benzyl-L-glutamate N-carboxyanhydride (gamma-Bn-Glu NCA) using aminopropyl isobutyl-POSS as a macroinitiator. The incorporation of POSS units at the chain ends of PBLG moieties has two important effects: allowing intramolecular hydrogen bonding between the POSS and PBLG units to enhance the latter's a-helical conformations in the solid state and preventing the aggregation of nanoribbons through the POSS blocks' protrusion from the ribbons to allow the formation of clear gels in solution.