Modulating Morphologies and Surface Properties of Nanoparticles from Cellulose-Grafted Bottlebrush Copolymers Using Complementary Hydrogen-Bonding between Nucleobases.

Abstract

Herein we report the synthesis of a cellulose-grafted bottlebrush copolymer with nucleobases as hydrophobic moieties. Well-defined spherical micelles from this bottlebrush copolymer were fabricated via a solvent switch method. A morphological transition from spheres to worms was only observed to occur when a diblock copolymer with a complementary nucleobase functionality was introduced. Hydrophobic interaction is not capable of triggering the morphological transformation, and the diblock copolymer with the heterogeneous acrylamide nucleobase monomer can induce the morphological transition at higher A:T molar ratios, which might be caused by the weak H-bonding interaction. This supramolecular "grafting to" method enables the preparation of a series of nanoparticles with similar shapes and dimensions but distinct surface properties such as zeta potentials. Moreover, reversible morphological transitions between worm-like micelles and spheres can be achieved using a reversible collapsing and swelling of a thermoresponsive polymer. This work highlights that a supramolecular "grafting to" approach between complementary nucleobases can be utilized to tune morphologies and surface properties of nanoparticles.