Alkynylated Cellulose Nanocrystals Simultaneously Serving as Chiral Source and Stabilizing Agent for Constructing Optically Active Helical Polymer Particles

Abstract

To take advantage of the chirality of cellulose nanocrystals (CNCs) and to develop novel chiral polymer materials, alkynylated CNCs (alkynyl-CNCs) were prepared and copolymerized with an achiral acetylenic monomer through suspension polymerization in aqueous media. The chirality of the alkynyl-CNCs was efficiently transferred to racemic helical polymer chains, by which inducing predominantly one-handed polymer helicity. Moreover, alkynyl-CNCs simultaneously acted as a comonomer and stabilizing agent, directly providing optically active microparticles (400–800 μm) constructed by chirally helical polymer chains. So the alkynylated CNCs played triple roles in our strategy: chiral source, comonomer, and stabilizing agent for performing suspension polymerizations. SEM images showed the successful formation of microparticles with regular spherical morphology, while circular dichroism spectra demonstrated the formation of one-handed helical polymer chains and optical activity of the microparticles thereof. The p...