Molecular Weight and Functional End Group Control by RAFT Polymerization of a Bisubstituted Acrylamide Derivative

Controlled radical polymerization of the bisubstituted acrylamide derivative N -acryloylmorpholine (NAM) has the potential to yield telechelic polymers, one end of which can subsequently be grafted to latex particles. Once grafted, the other chain end of the polymer can be used as an immobilization site for species with applications in molecular biology and biomedicine. The controlled polymerization of NAM using reversible addition−fragmentation chain transfer (RAFT) is performed using two new chain transfer agents S C(Z)−SR bearing the same functional propanoic acid group (R) and two different Z groups, benzyl (CTA 1) and phenyl (CTA 2). RAFT polymerization of NAM mediated by CTA 1 is very fast (>80% conversion in less than half an hour at 65 °C). The linear evolution of M̄ n and the low polydispersity indices ( M̄ w / M̄ n < 1.2) are in accord with the expected characteristics of a living polymerization. CTA 2 leads to broader M̄ w / M̄ n 's (<1.4). The resulting CTA-capped polymers were further used to yield an amphiphilic polyNAM- block -polystyrene. These α,ω-functionalized polyNAM chains were characterized by 1 H NMR and MALDI-ToF mass spectrometry.