Unimolecular Nanocontainers Prepared by ROP and Subsequent ATRP from Hydroxypropylcellulose

Hydroxypropylcellulose (HPC) is used as a macroinitiator for ring-opening polymerization of ε-caprolactone for the synthesis of a high molecular weight comb polymer consisting of a cellulose backbone and PCL grafts. The PCL end groups are converted into initiating sites for ATRP and chain extension of the PCL block is performed through grafting of tert -butyl acrylate to different lengths. The comb block copolymers are thereafter converted to amphiphilic polymers through deprotection of the tert -butyl group by acidic treatment, resulting in PCL- block -PAA grafts. These block copolymers are suspended in water and cross-linked using a water-soluble diamine to different attempted cross-link densities. Initial studies of the solubilization and encapsulation capacities of the amphiphilic polymers are performed using the hydrophobic model compound pyrene.